What annoys me today in marketing and media that too often today then talking on hi-fi, science is replaced by bizarre belief structures and marketing fluff, leading to a decades-long stagnation of the audiophile domain. Science makes progress, pseudo-science doesn’t. Hi-fi world is filled by pseudoscience, dogma and fruitloopery to the extent that it resembles a fundamentalist religion. Loudspeaker performance hasn’t tangibly improved in forty years and vast sums are spent addressing the wrong problems.
Business for Engineers: Marketers Lie article points tout that marketing tells lies — falsehoods — things that serve to convey a false impression. Marketing’s purpose is to determining how the product will be branded, positioned, and sold. It seems that there too many snake oil rubbish products marketed in the name of hifi. It is irritating to watch the stupid people in the world be fooled.
In EEVblog #29 – Audiophile Audiophoolery video David L. Jones (from EEVBlog) cuts loose on the Golden Ear Audiophiles and all their Audiophoolery snake oil rubbish. The information presented in Dave’s unique non-scripted overly enthusiastic style! He’s an enthusiastic chap, but couldn’t agree more with many of the opinions he expressed: Directional cables, thousand dollar IEC power cables, and all that rubbish. Monster Cable gets mostered. Note what he says right at the end: “If you pay ridiculous money for these cable you will hear a difference, but don’t expect your friends to”. If you want to believe, you will.
My points on hifi-nonsense:
One of the tenets of audiophile systems is that they are assembled from components, allegedly so that the user can “choose” the best combination. This is pretty largely a myth. The main advantage of component systems is that the dealer can sell ridiculously expensive cables, hand-knitted by Peruvian virgins and soaked in snake oil, to connect it all up. Say goodbye to the noughties: Yesterday’s hi-fi biz is BUSTED, bro article asks are the days of floorstanders and separates numbered? If traditional two-channel audio does have a future, then it could be as the preserve of high resolution audio. Sony has taken the industry lead in High-Res Audio.
HIFI Cable Humbug and Snake oil etc. blog posting rightly points out that there is too much emphasis placed on spending huge sums of money on HIFI cables. Most of what is written about this subject is complete tripe. HIFI magazines promote myths about the benefits of all sorts of equipment. I am as amazed as the writer that that so called audiophiles and HIFI journalists can be fooled into thinking that very expensive speaker cables etc. improve performance. I generally agree – most of this expensive interconnect cable stuff is just plain overpriced.
I can agree that in analogue interconnect cables there are few cases where better cables can really result in cleaner sound, but usually getting any noticeable difference needs that the one you compare with was very bad yo start with (clearly too thin speaker wires with resistance, interconnect that picks interference etc..) or the equipment in the systems are so that they are overly-sensitive to cable characteristics (generally bad equipment designs can make for example cable capacitance affect 100 times or more than it should). Definitely too much snake oil. Good solid engineering is all that is required (like keep LCR low, Teflon or other good insulation, shielding if required, proper gauge for application and the distance traveled). Geometry is a factor but not in the same sense these yahoos preach and deceive.
In digital interconnect cables story is different than on those analogue interconnect cables. Generally in digital interconnect cables the communication either works, does not work or sometimes work unreliably. The digital cable either gets the bits to the other end or not, it does not magically alter the sound that goes through the cable. You need to have active electronics like digital signal processor to change the tone of the audio signal traveling on the digital cable, cable will just not do that.
But this digital interconnect cables characteristics has not stopped hifi marketers to make very expensive cable products that are marketed with unbelievable claims. Ethernet has come to audio world, so there are hifi Ethernet cables. How about 500 dollar Ethernet cable? That’s ridiculous. And it’s only 1.5 meters. Then how about $10,000 audiophile ethernet cable? Bias your dielectrics with the Dielectric-Bias ethernet cable from AudioQuest: “When insulation is unbiased, it slows down parts of the signal differently, a big problem for very time-sensitive multi-octave audio.” I see this as complete marketing crap speak. It seems that they’re made for gullible idiots. No professional would EVER waste money on those cables. Audioquest even produces iPhone sync cables in similar price ranges.
HIFI Cable insulators/supports (expensive blocks that keep cables few centimeters off the floor) are a product category I don’t get. They typically claim to offer incredible performance as well as appealing appearance. Conventional cable isolation theory holds that optimal cable performance can be achieved by elevating cables from the floor in an attempt to control vibrations and manage static fields. Typical cable elevators are made from electrically insulating materials such as wood, glass, plastic or ceramics. Most of these products claim superior performance based upon the materials or methods of elevation. I don’t get those claims.
Along with green magic markers on CDs and audio bricks is another item called the wire conditioner. The claim is that unused wires do not sound the same as wires that have been used for a period of time. I don’t get this product category. And I don’t believe claims in the line like “Natural Quartz crystals along with proprietary materials cause a molecular restructuring of the media, which reduces stress, and significantly improves its mechanical, acoustic, electric, and optical characteristics.” All sounds like just pure marketing with no real benefits.
CD no evil, hear no evil. But the key thing about the CD was that it represented an obvious leap from earlier recording media that simply weren’t good enough for delivery of post-produced material to the consumer to one that was. Once you have made that leap, there is no requirement to go further. The 16 bits of CD were effectively extended to 18 bits by the development of noise shaping, which allows over 100dB signal to noise ratio. That falls a bit short of the 140dB maximum range of human hearing, but that has never been a real goal. If you improve the digital media, the sound quality limiting problem became the transducers; the headphones and the speakers.
We need to talk about SPEAKERS: Soz, ‘audiophiles’, only IT will break the sound barrier article says that today’s loudspeakers are nowhere near as good as they could be, due in no small measure to the presence of “traditional” audiophile products. that today’s loudspeakers are nowhere near as good as they could be, due in no small measure to the presence of “traditional” audiophile products. I can agree with this. Loudspeaker performance hasn’t tangibly improved in forty years and vast sums are spent addressing the wrong problems.
We need to talk about SPEAKERS: Soz, ‘audiophiles’, only IT will break the sound barrier article makes good points on design, DSPs and the debunking of traditional hi-fi. Science makes progress, pseudo-science doesn’t. Legacy loudspeakers are omni-directional at low frequencies, but as frequency rises, the radiation becomes more directional until at the highest frequencies the sound only emerges directly forwards. Thus to enjoy the full frequency range, the listener has to sit in the so-called sweet spot. As a result legacy loudspeakers with sweet spots need extensive room treatment to soak up the deficient off-axis sound. New tools that can change speaker system designs in the future are omni-directional speakers and DSP-based room correction. It’s a scenario ripe for “disruption”.
Computers have become an integrated part of many audio setups. Back in the day integrated audio solutions in PCs had trouble earning respect. Ode To Sound Blaster: Are Discrete Audio Cards Still Worth the Investment? posting tells that it’s been 25 years since the first Sound Blaster card was introduced (a pretty remarkable feat considering the diminished reliance on discrete audio in PCs) and many enthusiasts still consider a sound card an essential piece to the PC building puzzle. It seems that in general onboard sound is finally “Good Enough”, and has been “Good Enough” for a long time now. For most users it is hard to justify the high price of special sound card on PC anymore. There are still some PCs with bad sound hardware on motherboard and buttload of cheap USB adapters with very poor performance. However, what if you want the best sound possible, the lowest noise possible, and don’t really game or use the various audio enhancements? You just want a plain-vanilla sound card, but with the highest quality audio (products typically made for music makers). You can find some really good USB solutions that will blow on-board audio out of the water for about $100 or so.
Although solid-state technology overwhelmingly dominates today’s world of electronics, vacuum tubes are holding out in two small but vibrant areas. Some people like the sound of tubes. The Cool Sound of Tubes article says that a commercially viable number of people find that they prefer the sound produced by tubed equipment in three areas: musical-instrument (MI) amplifiers (mainly guitar amps), some processing devices used in recording studios, and a small but growing percentage of high-fidelity equipment at the high end of the audiophile market. Keep those filaments lit, Design your own Vacuum Tube Audio Equipment article claims that vacuum tubes do sound better than transistors (before you hate in the comments check out this scholarly article on the topic). The difficulty is cost; tube gear is very expensive because it uses lots of copper, iron, often point-to-point wired by hand, and requires a heavy metal chassis to support all of these parts. With this high cost and relative simplicity of circuitry (compared to modern electronics) comes good justification for building your own gear. Maybe this is one of the last frontiers of do-it-yourself that is actually worth doing.
1,557 Comments
Tomi Engdahl says:
Opas: Kaapelit äänen- ja kuvantoistossa
https://avplus.fi/opas-kaapelit-aanen-ja-kuvantoistossa/
Tomi Engdahl says:
https://www.thomann.de/blog/fi/7-vinkkia-kotistudion-kaapelointiin/
Tomi Engdahl says:
OFC vs. CCA eli virta- ja kaiutinkaapelin valinta
https://www.fanaticaudio.com/posts/ofc-vs-cca-eli-oikean-kaapelin-valinta/
Mitä eroa on täyskuparilla ja alumiinikaapelilla?
Otsikon kysymys on ehkä yksi useimmin kysytyistä kysymyksistä mihin nykyään saa vastata autohifimyyjän ammatissa. Tässä pieni tietopaketti kahden yleisimmän kaapelityypin eroista. Aloitetaan termeistä eli mitä ne kaapelit oikeasti ovat:
OFC tulee sanoista Oxygen Free Copper eli suomeksi happivapaa kupari. Kuparin puhtausaste on yleensä 99,99% tai yli sen. Eli jotain muuta kuin kuparia on johtimessa vähemmän kuin prosentin sadasosan verran. Tästä syystä lienee saanut alkunsa termi “täyskupari”.
CCA tulee sanoista Copper Cladded Aluminium eli suomeksi kuparipinnoitettu alumiini. Näissä kaapeleissa se koostumus vaihteleekin sitten todella paljon. Joissain kaapeleissa, mitä olen nähnyt mainostettavan CCA-kaapeleina, ei ollut kuparia ollenkaan, vaan johtimena oli aivan pelkästään alumiinia. Joissain kaapeleissa taas kuparia voi olla jopa puolet johtimen määrästä. Yleisimpiä sekoitussuhteita lienee sellaiset joissa kuparia on 20-40 % ja alumiinia 60-80 %.
Miten OFC ja CCA kaapelin voi erottaa toisistaan?
Paino. Helpoin tapa erottaa kaapelit toisistaan, on paino. Alumiinin ominaispaino on 2,7 kg/litra ja kuparin 8,9 kg/litra. Eli litra alumiinia painaa 2,7 kiloa ja litra kuparia 8,9 kiloa. Eli kupari painaa 3,3 kertaa enemmän kuin alumiini. Tietty painovertailu on vaikeaa jos ei ole vertailukohtaa tai aikaisempaa havaintoa kaapeleiden painosta.
Väri. Alumiini on alumiinin väristä ja kupari kuparinväristä, aika loogista. Tosin CCA-kaapelissa on nimensä mukaisesti säikeiden pinnalla ohut kerros kuparia joten CCA-kaapeli näyttää usein kuparikaapelilta kun sitä kuorii. Mutta kun kaapelin leikkaa poikki, useimmiten poikkileikkauksen väristä huomaa eron. Tai raaputtamalla säikeen pintaa. Jos kuparin alta paistaa alumiini, on kyseessä CCA-kaapeli.
Koska molemmat ovat pehmeitä metalleja, helpohkoja muovattavia ja sähkönjohtavuudeltaan hyviä, ne soveltuvat hyvin esimerksi johtimien valmistukseen. Kumpikaan metalli ei myöskään ruostu vaan molemmilla on taipumus hapettua. Hapettunut pinta toimii myös suojakerroksena joka suojaa metallia hapettumisen etenemiseltä syvemmälle metalliin.
Eroavaisuuksista mainittakoon että alumiini on moninkertaisesti kevyempää. Ja kupari taas sähkönjohtavuudeltaan parempaa.
Kuinka paljon parempi johdin kupari on?
Alumiinin sähkönjohtavuus on noin 65% kuparista. CCA-kaapelissa ero on hieman pienempi koska kuparipinnoite parantaa jonkin verran sähkönjohtavuutta verrattuna pelkkään alumiiniin. Parannus on noin 10% eli tässä tapauksessa se tarkoittaa sitä, että CCA-kaapelin sähkönjohtavuus on noin suurin piirtein 70% OFC-kaapelista ( 0,65×1,1=0,715 ).
Muita eroja kuin sähkönjohtavuus? Onko niitä?
CCA-kaapelit tulivat markkinoille noin kymmenen vuotta sitten. Sinä aikana niistä on kertynyt aika paljon kokemuksia. CCA-kaapelit käytännössä hapettuvat herkemmin kuin OFC-kaapelit. Mutta CCA-kaapeleiden hapettumisessakin on eroja. Toiset hapettuvat hieman OFC-kaapelia nopeammin ja toiset todella paljon nopeammin. Muutaman vuoden vanhoja CCA-kaapeleita on nähty sellaisen töhnän peitossa ja peittämänä että kaapelin ja sen liitosten johtavuus on ollut jo todella heikko. Mutta myös vastakkaisia esimerkkejä joissa hapettumista on ollut hyvin vähän.
Kumpaa kaapelia sitten pitäisi valita?
Minun mielestäni KAIKKI muut seikat puoltavat OFC-kaapelia, paitsi hinta ja paino. Siksihän CCA-kaapeleita on alunperinkin alettu valmistaa koska kupari on moninverroin kalliimpi materiaali kuin alumiini. Kuparin hinnannousu on ollut jatkuvaa jo vuosikaudet.
Lopputulos:
Jos budjetti kestäää, osta OFC-kaapelia. Jos taas ei kestä, osta CCA-kaapeli.
Tomi Engdahl says:
https://uraltone.com/blog/uraltone-kitarakaapeli-testeri-kuuntele-ja-totea/
Kitarakaapelien soundierot on ainainen kuumaperuna! Joidenkin mielestä kaapeleissa ei ole mitään eroa, toisten mielessä vain 69€ ja sitä kalliimmat kaapelit on käyttökelpoisia. Toiset vannovat perinteisten juotettavien kaapelien ja liittimien perään, toiset taas hyväksyvät vain mekaanisesti liitettävät (solderless) liittimet ja niihin sopivat kaapelit.
Useammat meistä ei ole koskaan AB(CDE…)-testannut kaapeleita. Näkemykset on pakko pohjata internet keskusteluihin ja artikkeleihin. Valmistimme UralTone earteaser -kaapelien sounditesterin. Testeri kytketään kitaran ja vahvistimen väliin. Testeriin saa kytkettyä 6 erilaista kaapelia. Kiertokytkimellä ohjataan ääni eri kaapelien kautta. Näin kuulee suoraan erot eri kaapelin välillä.
Testeri on kokeiltavana myymälässämme! Tervetuloa käymään ja toteamaan itse miltä eri kaapelit soundaa, vai soundaako miltään.
No, onko tässä tarkoitus kettuilla kaapeliuskovaisille vai uskommeko , että kaapelien välillä on niin isoja merkittäviä eroja, että ne kannattaa valita kuuntelemalla?
Ei kumpaakaan. Kaapeleiden mahdolliset soundierot johtuvat kaapelin kapasitanssista. Tyypillisesti kapasitanssit on välillä 52-150pf metriltä. Siis 6 metrin kitaran kaapelin kapasitanssi vaihtelee välillä n. 300-900pF. Kaapelin kapasitanssi muodostaa sen molemmissa päissä olevien piirien kanssa filtterin, joka muuttaa äänen taajuusvastetta. Eli teoriassa eroja on. Kuinka merkittäviä ne on, riippuu pitkälti käyttäjästä ja soittajasta, ja tietysti suurimmilta osin kaapelin pituudesta.
Toki kaapeleissa on muitakin speksejä, kuten resistanssi ja induktanssi, mutta nämä ovat niin pieniä, ettei niillä ole merkitystä ääneen.
Tärkeimpänä ominaisuutena kaapelien valinnassa pidän kestävyyttä ja käyttömukavuutta (esim. taipuisuus) kunhan kaapeli on riittävän hyvää teknisesti.
Sommer cable Spirit LLX on taas erittäin matalakapasitanssinen kaapeli, itseasiassa maailman matalakapasitanssisin kitarakaapeli, jota kannattaa käyttää silloin kuin haetaan soundiltaan ehdottoman väritöntä kaapelia tai silloin kun vedot ovat pitkiä. Kaapeli on paksumpaa eikä mene solmuun niin helposti kuin erittäin taipuisat peruskaapelit.
Tomi Engdahl says:
Audio Interconnect Comparisons
https://sound-au.com/articles/cable-compare.html
Introduction
Audio interlinks can be bought for prices ranging from a few Euros to hundreds if not thousands of Euros. For some people, this is loose change, for others, this is hard-earned cash. Does spending this hard-earned cash on an expensive cable upgrade improve the quality of ones beloved audio gear, or does it merely finance the gold plating of some executive’s Humvee?
The Internet is filled with pages talking about the sense and nonsense of high quality audio interlinks. But quoting theory and numbers isn’t going to decide this issue. Therefore, I set out to put some to the test. Not by double blind testing that will be disputed (or ignored) forever, but by using measurement techniques that will yield clear and audible results.
Measuring methodology and equipment
There are a couple of pieces of equipment used for testing:
Digital PC scope: Velleman PCS100.
Function generator: Gwinstek GFG 8015G.
Meter used to measure cable resistance: Velleman DVM890 digital multimeter.
Meter used to measure cable capacitance and inductance: Velleman DVM6243 digital LC meter.
Source for recording: Samsung YP-U2 mobile music player.
Recording device: Creative Soundblaster Live!
However, I designed and built the most important piece of equipment myself: a difference amplifier. The numbers collected by the scope and function generator are helpful, but in the end, it’s the recordings that will tell the story.
Tomi Engdahl says:
What is linear and non linear things?
https://gearspace.com/board/audio-student-engineering-production-question-zone/1167609-what-linear-non-linear-things.html
A linear system has output in direct proportion to input.
A nonlinear system has output that is *not* proportional to input.
An ideal wire is linear: double the input voltage, double on the measured end.
A diode is nonlinear: current is not linear with respect to voltage.
A compressor relies on creating nonlinearity, were it linear it would be doing nothing…
P.s. – wrong sub, this s/b in geekslutz. Mod will probably move.
From a practical standpoint you can think of it like this:
[input value] -> [device] -> [output value]
If the output value is equal to the input value, then the device is linear.
Tomi Engdahl says:
The Naked Truth about Speaker-Cables
Bananas, bananas. More lengths of cable talk we have to do….
https://www.tnt-audio.com/clinica/spkcbl_e.html
Tomi Engdahl says:
Speaker cables don’t influence harmonic distortion!
https://www.diyaudio.com/community/threads/speaker-cables-dont-influence-harmonic-distortion.320870/
Tomi Engdahl says:
Radio Frequency (RF) Analysis of Speaker Cables/Reflections
https://www.audiosciencereview.com/forum/index.php?threads/radio-frequency-rf-analysis-of-speaker-cables-reflections.7154/
Tomi Engdahl says:
Why Audio Cables Sound Different
Blog, Fresh Rants, Knutz And Boltz
https://www.audioresurgence.com/2019/09/why-audio-cables-sound-different.html
First off, let me make it very clear:Do audio cables make a difference to sound
I do NOT fall into the ‘naysayer’ camp of audiophiles who claim that all cables sound the same.
I AM NOT in the camp of audiophiles who claim that expensive cables, by definition, must sound better than cheaper cables since they are more expensive.
o make things clear I’ll present my conclusions now, at the start of this article, then show you quite simply how I’ve arrived at them.
Conclusion #1 – A cable’s electrical properties can be measured. In doing so we find there are a number of significant differences between different cables designed to do the same job. These measurable differences in the electrical properties of cables can be correlated directly to the differences we hear in the sonic profiles of cables. [more later]
Therefore measurable differences in the electrical properties of audio cables can and do affect how the music sounds and in a predictable way.
Conclusion #2 – Since each Interconnecting cable has its own set of electrical properties that impact the passage of signal, they should be considered to be an actual component of a three-component ‘electrical system’. An example of a 3-component electrical system in this context is a preamp and power amp with an interconnecting cable. All cables, even inexpensive ones, have a unique combination of electrical properties. Changing a cable to one involving different design parameters, materials, construction methods, etc, will introduce a new set of electrical properties into the system and we would therefore expect the resultant sound of the system to change. The new cable’s properties may act sympathetically with the remaining components, or not. Therefore the resultant sound might be better, or not. Since acting ‘sympathetically’ in this context is entirely subjective, it is impossible to predict the outcome based on the cost of the cable. In some sense, it’s almost a case of rolling the dice and hoping for a set of electrical properties to appear that sound good. Like rolling five sixes.
Therefore cost has no bearing on how a cable will ‘sound’. (assuming the requisite level of competence in design and construction).
Let’s approach this via a circuitous route, by posing two questions: “Why do manufacturers go to such great lengths to make their exotic cables if you’re saying they can be outperformed by cheap cables, and why does anyone buy them?”
The answer isn’t so simple. There are legitimate reasons to consider and I’ll list a couple of those below.
So, why do we buy expensive audio cables?
People want new things to buy and that drives people to create new things to sell. But not everyone wants their chair to have the same square legs as other chairs, so there’s a consumer-driven need to create more choice and these choices must be available at different price points to satisfy the buying market from its low end all the way up to the top. [True]
It’s important to use quality cables in a high-end audio system because they pass important low-level signals [True]
The perception created mostly by the audio press is that of ‘cables are components’ [True] so as much time, energy, and money should be poured into cable selection as with any other active component. [False]
Using exotic components and esoteric manufacturing techniques to build audio cables means that more of the precious low-level signal will get from point A to point B unmolested. Obviously these exotic cables come at a cost, but it’s worth it given the investment you already have in your system. [False, mostly]
OK, let’s get down to the nitty-gritty. Before I do that, a simple disclaimer is necessary:
There are right ways and wrong ways to approach cable design and construction. There are good materials one can choose and there are poor materials. In everything I say in this article about inexpensive cables competing favorably with more expensive and exotic designs, I’m assuming that there’s a requisite level of competence that has gone into the design and build of said cheap cables. Yes, some cheap cables are dreadful, it’s because they’ve been improperly designed and/or constructed for their intended application. So you can come up with a lot of examples of cables that just sound like crap, but for the sake of our sanity, let’s just give thoughtful consideration to the performance of cables that have been well designed and built.
So we have a cable with some electrical values stated by the manufacturer, and we now understand how all of this works, so we can now calculate how a cable will sound, right?
Not so fast!
Remember how we said that the cable is an active component in a 3-component electrical system? Well, how a specific cable affects the overall sound will depend not just on the cable itself but what feeds into it and what the cable feeds into. Thus considering our example with the pair of RCA cables between a preamp and power amp: the way the cable affects the sound of the system as a whole will depend not on the cable itself, but on at least three important things, two of which have nothing to do with the cable itself:
The electrical properties of the preamp output (its output impedance*)
The electrical properties of the cable (all the measurable values we’ve talked about above)
The electrical properties of the power amp (its input impedance*)
We think, generally, that a lower resistance cable conductor is going to make our cable sound better than something with higher resistance and impedance. So we select oxygen-free copper or five 9’s silver as a conductor and we pay attention to the cable’s length, its gauge, hence, its overall impedance.
But they’re just a few of the basic electrical properties in a complex electrical system. We can’t possibly know how every cable will perform in areas such as skin-effect when passing an alternating audio signal. What about EMI/RFI susceptibility in our Teflon insulated silver wire with no external shielding? There are just too many unknown variables that are fed into our equation with too few electrical constants.
The end result is that we CAN perform due diligence when selecting our cables by looking at their electrical properties, reading the subjective reviews of others using the cable in a completely different system, paying much more than makes any sense, in the hope that more money equates to better performance, etc, but all we can do from there is to simply hope for the best.
Fortunately, if our new $2000 cable sounds like crap, all is not lost. Remember, cables need time to break-in. Even if you move them a little they need some time to ‘settle’ before they’ll perform at their best. What that really means is that you’re giving your ears and your brain time to adapt to the specifics of your new noise.
Back to the point: So, what happens when we pick our cable from the many available, and the combination of all of its electrical properties when added into our system, makes the overall sound worse than when using the cheaper cable it replaced? The answer is simple. If it sounds bad it is bad. Not that it’s a ‘bad’ cable, just that it doesn’t work well in your system. So get rid of it.
Tomi Engdahl says:
Cable Design and the Speed of Sound, Part Two
https://www.psaudio.com/copper/article/cable-design-and-the-speed-of-sound-part-two/
Tomi Engdahl says:
https://www.analogictips.com/use-nonlinear-amp/
Tomi Engdahl says:
Linear vs Non-Linear Distortion
https://www.reddit.com/r/audiophile/comments/8aoqfg/linear_vs_nonlinear_distortion/
I just read an article by Nelson Pass that talked about negative feedback and it’s characteristics. The focus, though, was about the distortion that is introduced when negative feedback is used. But what I didn’t know was that the different types of distortion I know about are non-linear.
There are linear and non-linear forms of distortion. Linear distortions affect the amplitude and phase of audio signals, but don’t show up on harmonic distortion analyzers as added frequency components that weren’t there in the first place. Tone controls are a good example of circuits with linear distortion. Nonlinear distortions are those which add new frequency components to the original signal, either as harmonic multiples of the original frequencies or as sidebands resulting from their non-linear interaction between the original frequencies.
My question is this: why is harmonic distortion and intermodulation distortion (and possibly other distortions that I don’t know about) non-linear? From what I understand, those distortions increase proportionally with an increase in volume from an amplifier or speaker or any other component. Doesn’t that make it linear? Or is there a different, scientific definition of the quality of being linear or non-linear that I am ignorant of? Thanks for helping me cure my ignorance!
It boils down to this: https://en.wikipedia.org/wiki/Nonlinear_distortion
It basically boils down to whether a change in input amplitude causes a corresponding change in output. Let’s say you have an amplifier that produces 10V of output with 1V input. If the amplifier was perfectly linear, it would produce an output of 20V of output for 2V of input. An amplifier that isn’t perfectly linear could for instance instead produce 18V of output.
The result of this is that it will (in some way) alter the shape of the input signal relative to the output signal, which in turn adds frequency components to the output signal that aren’t present in the original signal.
Linear distortion on the other hand, is an anomaly in the response of a system that is independent of the amplitude of the input signal – such as the frequency response variations in a speaker
Tomi Engdahl says:
Resistor non-linearity – there’s more to Ω than meets the eye
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiV1OWL2c76AhUPmIsKHbakCIM4ChAWegQICRAB&url=https%3A%2F%2Fconvexoptimization.com%2FTOOLS%2FSimonVishay.pdf&usg=AOvVaw3PfVim8zyA1-HTkexvvQiO
We know that resistors come in different values from a few thousandths of an ohm to tens of millions
of ohms. They also come with wattage ratings from milliwatts to thousands of watts. There are
also maximum voltage ratings; even though we may not exceed a power rating in use there will be
limits on the maximum voltage across the resistor and even from the resistor to nearby grounded
surfaces. Resistors also have temperature ratings. They may range from a change in resistance as
low as 1 part per million of their initial resistance per degree C change in temperature to several
thousand PPM/C changes. There are also changes in value with applied voltage. Most of this information
is standardized and available from the manufacturers for their products.
The basic equation for resistors is Ohms Law I x R =E. This rule was based on the observation of how
voltage and current are related. However as nothing is ever perfect there are always deviations from
the rule.
I decided to do some tests to see how real resistors behave under conditions typical of audio circuitry.
The basic test principle is that Ohms law is linear. One ohm plus one ohm equals 2 ohms. If there is
something causing distortion it will not be linear. If this is caused by a voltage across the resistor,
the more the voltage the greater the distortion should be. The
important characteristic is that since the distortion is not linear
the distortion caused by one volt across the resistor is not twice
(or half ) the distortion caused if there were two volts across the
same resistor!
Wrap-up This of course is
only one way to look at resistors.
Also, be aware that
actual resistor distortion
in a circuit will most probbably
be higher then the
reference numbers shown
with this self-comparison
type of testcircuit. But with
some thought you can influence
the performance
of your audio designs by
choosing parts for the
distortion and power handling
characteristics that
are in line with your design
goals.
Tomi Engdahl says:
https://www.polarisaudio.it/en/guide/audio-cables/the-types-of-conductors-the-6-things-to-know
Tomi Engdahl says:
Cables, characteristics and credulity
http://pspatialaudio.com/cables.htm
The type and quality of the metal used in cables is widely thought to be important in audio applications. Top-end cable prices are eye-watering and represent a significant investment for the vinylista. How much difference is there between a cheap cable and a high-end interconnect?
Silver wire is widely considered pre-eminent for analogue audio applications because it is the best conductor of electricity. Silver has a resistivity 7% lower than the next best conductor, copper. But, because silver is so rare and expensive, copper is the preferred metal for cables and has been since the invention of the telegraph in the 1820s.
The belief that audio cables, if they can’t be silver, must be of exceptional purity copper is widespread. This is justified in the case of the presence of other elemental metals which only need to be disolved in the copper in very low concentrations to affect radically its electrical properties.
For example, if aluminium is present as a solute element in copper at a low concentration of 0.2%, the electrical conductivity of the alloy will degrade by 15% compared with pure copper!
The need to reduce the oxygen in the metal is thought to be especially important by audiophiles. You will find reference to “oxygen impurities” everywhere on-line. But this is a misconception.
Copper is normally supplied and employed for cables of all types in a dilute alloy known as Electrolytic Tough Pitch (ETP) copper, which consists of very high purity metal deliberately alloyed with oxygen.
ETP copper is known as C11000 grade and is required to be 99.9% pure with a minimum conductivity of 100% according to the empirical International Annealed Copper Standard (IACS) measurement (see panel). ETP copper is near universal for electrical applications.
Oxygen-free
Two grades of copper (C10200 and C10100) with reduced introduced oxygen are available and which cable manufacturers incorporate in their products. These reduced oxygen coppers were not developed to offer greater purity. They were developed for applications in reducing atmospheres, in which the gases would be oxidized by any present oxygen in the metal, and for high-vacuum applications in which the oxygen in ETP copper would outgas.
Researchers in Korea³ discovered that a grown single-crystal wire demonstrated a resistivity reduction of 9% compared to the international annealed copper standard (IACS) — the resulting conductivity value being better than that of silver!
Most of the “single-crystal” wire in the audio business is made using the Ohno Continuous Casting (OCC) process which was developed by Atsumi Ohno of the Chiba Institute of Technology in Japan. The process employs a heated mold and drawing the solidifying copper from the mold at a very slow rate.
By this means, it is possible to cause the solidification process to start from the inside-out resulting in the formation of very long crystals in the metal, rather than the many short crystals which form in conventional casting when the material cools from the outside-in. In truth, the cable so produced is not mono-crystaline, but there are only a few crystals per metre of length.
Most of the “single-crystal” wire in the audio business is made using the Ohno Continuous Casting (OCC) process which was developed by Atsumi Ohno of the Chiba Institute of Technology in Japan. The process employs a heated mold and drawing the solidifying copper from the mold at a very slow rate.
By this means, it is possible to cause the solidification process to start from the inside-out resulting in the formation of very long crystals in the metal, rather than the many short crystals which form in conventional casting when the material cools from the outside-in. In truth, the cable so produced is not mono-crystaline, but there are only a few crystals per metre of length.
Oddly it seems very hard to get hold of data on the resistivity (or conductivity) of wire produced by the OCC process.
“At present, our production of single crystal copper material can reach 99.99997% (6N) purity…… Single crystal copper wire electrical conductivity is 20% higher than that of the gold.”
This is hardly a spectacular claim when normal ETP copper has a conductivity some 30% better than gold! Sadly, there are currently no official classifications for these specialty coppers and the IACS conductivity is not readily available, so it’s difficult to know what these OCC copper products actually offer in terms of electrical performance.
Conductivity and micro-diodes
In any case, the argument for the superiority of single-crytal copper wire and silver wire is hard to reconcile with straightforward electrical conductivity. For high-impedance (small signal) work, even 7% change in conductivity is a very marginal change. Substituting a 10m silver cable for a copper cable in a balanced 600Ω terminated circuit, will cause a change in level of 0.2% (0.02dB) — a change well below the Just Noticeable Difference (JND) threshold for loudness change. In a circuit where one metre cables feeds a standard 10kΩ input impedance, the changes will be two order of magnitude smaller still.
We have to look to something more exotic to explain the differences audiophiles ascribe to these high conductivity cables.
A more subtle conjecture is that the crystals (and crystal boundaries or grain boundaries) which make up processed copper of all grades can impede current as the electrons cross the crystal boundaries. Even worse, that these crystal boundaries may act as miniature diodes (micro-diodes) with an inherent non-linearity which distort low-level signals. Thus cables with fewer crystal grain boundaries will distort the signal less. OCC cable is especially praised for its lack of crystal boundaries which might otherwise interfere with low-level signals.
It must be said that neither classical electron nor quantum-mechanical theories of electrical conduction allow for such an “micro-diode” effect (see Appendix). Nonetheless, a solid empirical study of this putative mechanism was understaken by Doug Self who describes the development of an ultra-low-noise amplifier system so that low-impedance passive components to be tested for nonlinear distortion at extremely low signal levels (0.01% on a 200µV signal).
Self discovered no evidence of non-linearity in any of the components, including lengths of copper cables (of all types), tested at low levels. He says,
…..The results obtained are in a sense disappointing….. there are no unsuspected low-level nonlinearities in components likely to be used in audio systems. No new and intriguing design problems have been set.4
……..it would be nice to think that this red herring at least has been laid to rest.
High-frequency effects
Lastly, the marketeers of analogue audio cables – when they are not obsessing wth conductor purity – often invoke descriptions of physical effects relating to the propagation of high-frequency signals in cables. The importance of high propagation velocity and the minimisation of skin effect are particular favourites.
The problem here is the confusion of the requirements for cables for digital audio signals and those for analogue audio signals. The subjects of transmission lines and skin effect and how they relate to digital and analogue audio signals are covered in the panel.
If analogue audio cables aren’t transmisson lines plagued with skin effects and low-level micro-diodes, does this mean that the type of thin audio cables (“audio bootlaces”) you can buy at the airport and which come free with audio gear is the high-point of cable engineering?
The answer is no. Here are a few examples of applications in which an audio cable plays a significant part of the electrical circuit, and where, an inappropriate choice of cable can have a significant, deleterious effect.8
Low level, high impedance circuits. For example the cable carrying the output of a moving-magnet cartridge to the preamplifier where the wrong type of cable can introduce anomalous frequency-response issues at the top of the audio passband. At best, this may upset the tonal balance, and may even render quadraphonic needle-drops impossible to decode. What is needed here is a cable with low capacitance per unit length.
Digital audio circuits, where the cable must act as a transmission line — a cable with the correct characteristic (surge) impedance is required in this case.
Low level, unbalanced signal circuits, where the cable must have adequate screening to prevent hum. A dense, multi-stranded screen is required in this case.
The ideal cable would combine these attributes together. And we might add a few extra requirements. Thus, the cable should be:
Low capacitance,
Possess good screening,
Have a controlled impedance (ideally 75Ω for digital audio work).
Be small diameter, light and easy bent and routed (to make cabling more tidy).
Be reasonably attractive. Cables hardly add to the quality of our lives, so they may as well be as pretty as we can make them.
We chose a miniature, coaxial type cable with a central conductor of silver plated copper and a silver plated copper braid with a PTFE (Teflon™) dielectric.
Polytetrafluoroethylene (PTFE) has excellent dielectric properties — far superior to PVC or even polyethylene. The high quality of the dielectric enables the constructon of a small and light cable with excellent properties at high-frequencies.
The outer jacket of the cables is Teflon FEP™ (Fluorinated Ethylene Propylene) a material which shares PTFE’s useful properties of low friction contributes to the low mass of the cable (15g/metre) and to the excellent minimum bending radius of 10mm. The material is also transparent which means the attractive silver-plated screen is visible.
Tomi Engdahl says:
https://www.atlascables.com/design-conductors.html
Tomi Engdahl says:
The Sound of Copper vs Silver conductors
https://sw1xad.co.uk/sound-of-copper-vs-silver-conductors/
Disclaimer: Everything stated below is of generalizing nature. Furthermore, we are assuming that everything else is close to being equal i.e. the geometry and insulation of a conductor of both copper and silver conductors is identical and that the conductors themselves are of similar age.
It is widely acknowledged that different conductor materials tend to have a different sound character despite no apparent differences in how these materials measure in terms of their frequency response. Frequency response is a very crude parameter by its nature which cannot measure all audible, interactive and idiosyncratic non-linearities and other properties. So using it as a main decision making-factor for suitability in audio of a material in question can a bit spurious to say the least. Feel free to replicate following experiment at home. Connect round conductor wires made of 99.99% OFC copper and 99.99% fine silver of identical thickness to a spectrum analyzer and measure their frequency response, consecutively.
The result is, one will find no difference in frequency response between pure copper and pure silver everything else being equal. Surprised?
We think that pretty much disproves the myth that silver alloy conductors are “brighter” or are “thinner on bass” relative to copper because of frequency response differences. The technology or science might not be good at measuring many aspects of sound but frequency response curves of both identical geometry conductors are pretty similar if not identical. Nevertheless, ignoring conductor geometry and other factors for now, there exists a distinct difference of sound when both type of conductors are conducting signals of music.
The main sonic characteristics of pure copper vs pure silver conductors can be summarized as follows:
While copper tends to sound warmer and has more body it is a bit slower and less harmonically rich, silver does exactly the opposite. Silver tends to sound livelier, while offering more clarity and harmonic richness but at the cost of a colder character, thinner and lighter body. The differences in sound are clearly audible in the video clip below. The first sample is reproduced through an interconnect that is made of silver conductors and the second one that is made of copper.
Having crudely summarised the main sound characteristics of copper versus silver sound, one must acknowledge that we may be comparing “apples to pears” as there are many other factors that affect the sound signatures of both materials. Other factors may include : origin & age (new vs old), conductor geometry (round, flat, thickness, etc), insulation (dialectric material type, thickness, distance, etc), treatment & storage conditions (ambient temp, crygenics, annealing etc.), direction (wire drawing, manufacturing process), conductor purity – just to mention a few and many more.
It is difficult to imagine to live with a sound of either type of conductor if copper and silver sound exactly the opposite. It is really a matter of choice of other materials & components and customers preferences. Having said that, copper conductors tend to harmonise better with semiconductors, while silver tends to harmonise better with valves. For example, valves are warm sounding by nature (some are more and some are less depending on many other factors) and a silver conductor are naturally cold sounding conductor. If one combined them both, the sound is way maybe less warm than expected. If one combined valves with copper, the resulting sound may become overly warm and may appear less dynamic. On the other hand, if one combined silver with transistors, then silver tends to reveal deficiencies in linearity of transistors due to its semi-conductive grain structure, which is not ideal for long run listening sessions. Of course one can have a combination of silver and copper wiring as as with valves and transistors but silver and copper materials do not harmonise well together when wired in parallel. If one believes that one gets “the best of both worlds” of copper and silver sound one is mistaken as the resulting sound is characterized by dissonance of copper and silver “siblings rivalry”.
Now the cost factor- one ounce of 99.99% fine silver can easily cost about 10 times more than of copper. Consequently, cables made of fine silver conductors are not cheap and should theoretically cost 10 times more, ceteris paribus. Of course one can save on the amount of silver one employs in a cable but that comes at the cost of sound since the amount of silver employed is highly correlated with the presence or absence of mid bass. If one saves a bit here then the sounds becomes thin.
Last but not least, on the account of silver plated copper as a cost effective solution- it is the worst that can happen to a sound of a conductor for the reasons stated above. Relatively thick copper core meets ultra thin (not much above 100 microns) & irregularly covered “silver crust” should ideally be avoided by all costs and means as the silver plating process introduces non-linearities & dissonances in all audible frequency spectrum particularly in high frequencies which are characterized by noisiness and lack of clarity, which tend to cause serious peaks particularly in thinner conductors, no matter how thick the plating is.
Is it really a question of measurement error? The point of the article is that heterogeneity in sound signatures of different metallic conductors is not solely explained by frequency response measured by spectrum analyzers or other measuring equipment.
The lack of explanatory power of those measurements just illustrates the shortcomings of variables employed to explain sonic behavior that we use in physics. The point here is that we cannot explain certain sonic characteristics with the set of to us known variables. In other words, what we cannot measure it does not mean it does not exist!
Hello again
I very much agree that components including cables can have an audio signature depending on the materials used.
A difference I have not been able to verify safely with normal measurement of the signal ..
I do not know if you are aware that your recording on YouTube with a microphone shows a difference.
In that regard, I would like to know, is it one cable that has been replaced or more.?
Could there have been an error from sections 1 to 2 that has made the difference.? , a difference that is very clearly seen in the area without music.
Thanks in advance for the reply
Regards Torben
Hello Torben, the only difference between the 2 video recordings are the conductor type in just one pair of interconnects: in one video they are all copper in the other all silver conductors. All those differences are easily captured by a microphone as witnessed in those video clips
Tomi Engdahl says:
Conductor Design – some comments on the issue of importance of wiring
https://sw1xad.co.uk/technology_post/conductor-design-some-comments-on-the-issue-of-importance-of-cables/
Why cables are so important?
Ideal cable is a zero impedance conductor. Ideally, it would present zero impedance to a music carrying signal. Any serious imperfection of a conductor can only contribute to an impedance mismatch, which is the main issue for the signal transmission. In order to avoid it, the cables must “adapt” themselves to the impedance requirements across the source and the signal receiver. Everything matters when it comes to quality and quantity, whether it is the material of a conductor or the reactance of a complete cable.
Our non-ideal world is full of limitations dictated by the laws of physics. Unfortunately, there are no ideal components in a non-ideal world. Each conductive material has its own sonic character and is characterised by the residual presence of the three main electric properties such as resistance, inductance and capacitance. The combined interaction of these properties is called impedance. Since impedance depends on signal frequency, an impedance mismatch between the source (e.g. CD player) and the load (e.g. amplifier) act as signal frequency filter. All filters modulate signals and cause signal degradation.
In spite of all natural limitations, we should not accept a compromise on signal transmission. The main objective was to create a minimum compromise conductor, which maximises signal integrity and its transfer behavior while minimising the effects of as resistance, inductance and capacitance causing signal modulation or simply a loss of a signal integrity. In transmission line theory terms, we looked to design a conductor that would match the impedances (i.e. minimise the signal loss) between the signal source and the load more closely. After all, the main goal of a cable design is to maximise the signal transfer behavior i.e. minimise the impedance mismatch, overcoming the effects of resistance, inductance and capacitance.
Numerous experimentation with cable designs and investigation into the effect of conductor materials on the quality of reproduction of sound, led us to believe that the material quality of a conductor, its dielectric environment and construction are the most significant factors that affect the signal transmission.
Some of the findings can be summarised as follows:
Importance of the conductor material
Every conductive material does have a distinct sound signature. Without going into the debate of personal preferences, we find that solid, individually insulated conductors sound generally more revealing, dynamic and more musical. The way these conductors are arranged and treated is equally is important as their type and their purity.
Insulation around the conductors
What really makes a significant difference, we think is the dielectric or insulation material around conductors. A silver conductor of identical material quality can either shine or sound dull depending on the choice of the dielectric material. There many options here: polyurethane, PVA, cotton, silk, PTFT and many others. Some dielectrics are better with silver and some are worse. If a dialectic material sits to close on a conductive material and there are many conductors in parallel, the capacitance of a cable increases.
Air -the best real world attainable dielectric. While it is not possible to have a 100% air dielectric we strived to maximise its presence by intentionally making a use of oversized PTFE tubing (up to 5x the conductor thickness).
On the matter of cable construction
While conductor and insulation materials are crucial to the performance of a signal transmission, the arrangement of these materials is a factor of no less importance. There is almost unlimited number of combinations of choosing the size and the quantity of conductors and ways of how to arrange them. All these choices are different forms of a compromise. Too thin conductors sound excellent in the treble frequency region but usually sound poor in the bass frequency region, while for the thicker conductors the issue is vice versa. On the one hand any conductor twisting is undesirable since it increases inductance and resistance. On the other, paralleling many conductors decreases resistance but paralleling too close and too many increases capacitance too. Using a screen surely has benefits of shielding against RFI and other parasitic radio frequencies but brings a drawback of increased capacitance and reduction of airiness in the sound.
Tomi Engdahl says:
https://www.opusklassiek.nl/audiotechniek/cables.htm
Cable Parameters
The parameters which describe the cable electrically are series resistance, series inductance, shunt conductance, and shunt capacitance. These parameters can be determined by direct measurement and/or by calculation from elementary formulas. They depend entirely on the geometry of the cable and the nature of the conductors and the insulation used. The approximate values for a variety of cables made of copper wire and rubber or plastic insulation are summarized in Table I.
Conductors of copper, silver, or similar high-conductivity materials – regardless of the method of drawing the wire – behave similarly. The electrical properties of cables are not significantly affected, at audio frequencies, by the type of insulation used. The mechanical properties of the cable, however, may be more desirable with use of certain insulators and construction techniques.
The nature of the insulation, and whether or not the wire is ‘tinned’ have little effect on the electrical parameters of the cable at audio frequencies.
The accompanying Tables, based on my 1979 investigations. cover both ‘normal’ and selected ‘special’ cables. Three of the normal cables are typical two-wire pairs, such as standard zip cord with rubber insulation. Of these, the Nr. 12 zip cord is a European extension cable made by Lucas; its wires are more widely spaced than those of U.S. extension cords, giving it a slightly higher inductance. Two of the other normal cables are standard twisted-pair types in a vinyl jacket, normally used by professionals; these are available from Alpha, Belden, Consolidated, and other manufacturers. The RG-9 is a standard coaxial cable made, in this instance, by Belden.
Of the three types of special cables included, one is a large-gauge coaxial of dual-cylindrical construction by Mogami. Another is a braided cable by Cobra. The third is a plastic-jacketed pair of ‘welding size’ conductor real welding cables. I believe – from Fulton.
Present-day cables that deviate fro the techniques used to construct cables in 1979 usually use fine strands of wire which are gathered or braided in a variety of complex geometries. Some of these techniques increase and decrease the series inductance of the cable slightly. Both techniques, increasing and decreasing inductance, are claimed to improve the electrical properties of the cables. In the following discussion, it should be apparent that neither of these techniques makes much difference at audio frequencies.
The wire listed as Nr. 12 zip cord is a high-quality extension-cord style of construction with slightly greater than normal spacing. Thus, it has a slightly higher series inductance compared to domestic zip cord. This cable and the welding type fall just slightly outside the range of values for normal wires (one above and one below).
The issue of Litz-type wire construction, using a multitude of tiny strands, could be discussed at length, but at this point, let it be said that the topic is largely irrelevant at audio frequencies. There simply is no significance to ‘skin effect’ at audio frequencies, and wires which purport to fix this effect usually do not do so in any case.
Spacing the wire pair more closely has the advantage of reducing the series inductance. Unfortunately, this tactic also increases the shunt capacitance substantially. Various braided cables seem to attain a reduction of three or four times in the series inductance, but show a rise of 10 to 20 times in the capacitance. Whether the advantages of this type of construction outweigh the disadvantages will be considered later.
Some users have suggested spacing wires farther apart to give less ‘interaction’ between the wires. However, it is well known that the inductance of a cable rises as the wires are spaced farther apart.
Spaced wires not only interact more with each other but also show cross talk with other nearby pairs. Spacing the wires offers no advantages whatever and several serious disadvantages. This configuration should never be used and will not be considered further here.
Some regular coaxial cables have attractive values of inductance and capacitance. However, only a few of the larger sizes have large enough conductors to make them useful for loudspeaker connections.
Cables as Transmission Lines
When considering cables as transmission lines, thoughts come to mind of characteristic impedance, termination, matching, reflections, and frequency dispersion. All of these are valid concepts, but they are not usually considered for very short transmission lines. And indeed, any reasonable length loudspeaker cable is a very short line. The wavelength of a 20 kHz signal is about 10 miles (16 km). Thus, a 10-meter cable is 1/1,500 of a wavelength. Any fluctuations in the signal caused by reflections at the ends of this cable will take place at a frequency of 30 MHz. Or, to look at it another way, 1,500 iterations toward the final voltage distribution in the cable will take place every cycle at 20 kHz. One must conclude that there are absolutely no audio frequency effects related to these reflections for cables of any reasonable length.
It is fortunate that reflections in loudspeaker cables are irrelevant, since they are never matched at either the amplifier or the loudspeaker ends. In practice, both the source and the load are quite complex and frequency dependent. Nevertheless, it is interesting to take a look at the characteristic impedance of a typical loudspeaker cable, which is also quite complex.
For frequencies well above fm the cable behaves more ideally in the sense that there is no frequency dispersion in the line, and the impedance has reached a limiting value that is resistive. At lower frequencies, the impedance is complex, and the line contributes some frequency dispersion to the signal. When there is dispersion in the line, the high frequencies arrive at the end of the line ahead of the low frequencies. This happens because the line’s series inductive reactance is too small compared to its resistance.
The principles of transmission-line theory require that for purely distortionless transmission:
R/L = G/C Formula 4
Since G equals 0 for typical audio cables, it is impossible to make the line perfect. However, R should be made small and C should be made small as well. When this has been done to the greatest extent possible, then L should be made larger. The telephone company does just this by inserting loading coils in long lines to reduce dispersion distortion.
It would appear that reducing series inductance, as some special cables do, does not make much sense from a transmission-line viewpoint. When cables are considered as lumped element circuits, however, there are some good reasons to decrease all of the elements as much as possible; this will be discussed below.
Since all loudspeaker cables show some amount of loss and some dispersion, a vital question to be answered is: How much?
To determine the difference in the arrival times of the high frequencies compared to the low frequencies, we need to find the group velocity of the transmitted signal.
Dispersion characteristics for selected cables are shown in Table III for frequencies of 100 Hz and 10 kHz. From the Table, it is apparent that for a 10-meter cable, the delay differences are only a fraction of a microsecond – except for the braided construction, which is a little worse. In any case, the delay time, or frequency dispersion, is certainly not a problem for loudspeaker cables of any reasonable length.
A line will look much like a shunt capacitance when it is loaded with an impedance much higher than its characteristic impedance, and it will look like a series inductance when loaded by an impedance much lower than its characteristic impedance. Almost all loudspeaker cables are loaded according to the latter criterion. In general, playing numbers games with the high-frequency value of characteristic impedance for short cables at audio frequencies is largely useless.
Cables as Lumped Lines
It should be clear that treating loudspeaker cables as transmission lines, while interesting, is not of much direct design value. The loads are complex, the lines very short, and the frequencies too low to allow easy ideal treatment. Exact treatment is more complex than is warranted. In this section, loudspeaker cables will be treated as wire pairs that can be represented as lumped element equivalent circuits. This method will give reasonable design guidance and intuitively sensible results.
An ideal amplifier would be a voltage source with a Zo of zero. In fact, many high-quality amplifiers come very close to this ideal. At low and middle frequencies, the output resistance of an amplifier will typically be less than 0.05 ohm, with a rise to 0.2 ohm at the very highest frequencies. The output will usually be slightly inductive. Often a series inductance of 2 mH will be used to isolate the amplifier feedback loop from capacitive loads. This inductance is 0.25 ohm reactive at 20 kHz. A good amplifier should be stable for any load, including capacitive loads.
Since even the worst of the cables is only 0.2 μF for 10 meters, such a cable should not cause a good amplifier to become unstable or to ring. It would take 35 μF to resonate 2 μH at 20 kHz. Thus, amplifier/cable interaction problems in the audio band are not likely. However, it is known that some amplifiers will not tolerate even slightly capacitive loads. This is an amplifier design problem, not a cable problem, and should be dealt with at that level. It is easy to test amplifiers for load sensitivity problems, and those amps that are not satisfactory should be eliminated. We will assume that the amplifier/ cable interface question is settled by using a ‘good’ amplifier. The problem of fuse-protecting the output circuit is not trivial and will be discussed later.
With a good amplifier in place, the remaining electrical problems are related to how the loudspeaker loads the cable and interacts with it.
While the values of the series resistance and inductance for the cable are easily measured, well known, and well behaved, such is not true of the load. The simplest equivalent circuit for a loudspeaker will be a series resistor/inductor combination. But real loudspeakers consist of crossover networks with inductors, capacitors, resistors, transformers, and voice-coils, all in some complex combination. Fortunately, it is not necessary to consider all possible combinations but only some limiting, worst cases. At low frequencies, most loudspeakers become mainly resistive, and some have a rather low value of resistance. Often the lowest value is below the rated impedance. Let us assume that this value never gets lower than one-half the rated impedance. If the loudspeaker becomes inductive at higher frequencies, as most cone-type drivers do, there should be no problems worse than the low-frequency problems.
It is possible, however, with capacitive tweeters, ribbons, or some more unusual tweeters to have low- impedance effects in the loudspeaker at the high frequencies. It will therefore be wise to investigate resistive, capacitive, and inductive loads at about one-half the rated impedance at the high-frequency end of the spectrum as well. The low-frequency end of the spectrum will be taken as 20 Hz and the high-frequency end as 20 kHz.
For any realistic load, with some inductance, the cable inductance will be entirely swamped out by the load, of course. A second is the frequency at which the cable inductance and a highly capacitive load will resonate. The capacitive load is chosen as 4 μF, which would correspond to a 2-ohm impedance at 20 kHz. While such a load is quite unreasonable, it represents a possible worst case.
All of the frequencies are well above the audio spectrum.
It appears that, as common sense would tell us, one should not try to drive a loudspeaker of very low impedance at great distances, or that one should use higher impedance loudspeakers if long cables are necessary. With most normal listening room situations, the cables will be short enough so that no audio frequency problems arise from the loudspeaker cables. It is interesting to note that changing to larger wire has little effect on the high-frequency resonance or fall-off frequencies. Those frequencies are controlled by the series inductance. Thus: there is some rationale for using cables that have low series inductance. Standard coaxial construction of the cable seems to give all of the advantages of low series inductance without the serious disadvantages of high shunt capacitance.
Since most loudspeakers have their lowest impedance at low frequencies, there are some advantages in using physically larger wire, with its lower series resistance.
A large number of cables with resistive, capacitive, and real loudspeaker loads were measured using sensitive, broad-band, difference amplifier techniques. Resistive loads were more difficult to drive than typical loudspeakers. Capacitive loads were slightly more difficult still. Electrical problems of any kind (that is, phase shift, attenuation, dispersion, etc.) with 10-meter cables driving normal loudspeakers were just barely measurable using these refined measurement techniques. Absolutely no audible problems could be heard. The best solution to cable problems by far is to move the amplifier to the loudspeaker, thus making the cable very short.
Loudspeaker Considerations
When discussing wires used to connect amplifiers to loudspeakers, it would be wise to consider the residual effect of the wiring within the loudspeaker itself. At low frequencies, the worst offender is the series resistance of the low-pass crossover filter-in addition to the voice-coil resistance, of course. After all, 20 meters of Nr. 18 wire in an inductor introduces just as much resistance as 10 meters of Nr. 18 connecting cable from the amp to the speaker and back again. With essentially all loudspeakers that have internal crossovers and/or level-control pads, the internal resistance and inductance totally swamp out any possible small effects due to the connecting cable. These internal resistances of the crossovers and pads in a typical loudspeaker generally obviate the usefulness of the high damping factor of a typical amplifier. The only way to get the amplifier signal directly to the voice-coil is to use crossovers ahead of the amplifiers and multiple amplifiers. In very high-quality systems, elimination of the internal passive crossovers is a step that might be taken to obtain improvement of the sound.
Therefore, very good advice for improving a system and essentially eliminating cable concerns is to place the amplifiers at the loudspeaker and eliminate the crossovers by multi-amplifying the system with electronic crossovers. The problem of getting the low-level signal to the amplifier from the source is relatively simple
Fusing the Output Circuit
All of the above problems have been concerned with linear circuit elements. Ideally, the fuses used in the output circuit would be linear resistors as well. However, since they have to get hot, and melt, to burn out, they are actually non-linear elements in the output circuit. If fuses are to be useful, they must blow out when the system is used at some specified power level over the maximum desired. Typically, a fuse will increase in resistance to about three or four times its cold value just short of burnout. At 60% of full load, it will increase to about twice its cold value. The calculations and measurements of this section still show some possible problems with distortion caused by these changes in the fuse during normal program reproduction.
The time constants of typical fuses are such that heat and, consequently, resistance cycling can take place for normal musical beats at low frequencies.
There is no solution to this problem except over/using or not using fuses at all, unless the fuses are included within the feedback loop. This can be done, of course, by putting the fuses in the power-supply bus or even within the normal feedback loop.
Conclusion
It has been shown that loudspeaker cables need not be treated as transmission lines. It has also been shown that, in fact, transmission-line theory can give misleading results for very short lines, and that short lines should be treated as lumped lines. On the other hand, with poor choice of load and with longer cables, there may be some defects in phase or frequency response or some resonances introduced in the extreme upper audio frequency range.
It is clear that normal cables are suitable, and essentially perfect, compared to other defects in the transmission system – not the least of which is the loudspeaker crossover network and level-pad arrangement. The use of special cables, including normal coaxial cable, is not warranted except in a few extraordinary applications. And in those particular applications, short runs of cable would be a better solution.
Tomi Engdahl says:
https://www.audiosciencereview.com/forum/index.php?threads/can-anyone-explain-in-concrete-terms-how-the-plasmatron-helps.14752/
Tomi Engdahl says:
Cable Dielectric (Insulation)
In theory, the perfect cable is an un-insulated conductor floating in free air. In practice, there’s a bit more to it than that.
https://www.atlascables.com/design-insulation.html
Different frequencies occupy different (radial) positions within a conductor. Low frequency signals occupy the centre of a conductor, while the higher frequency signals are confined to the conductor’s surface. High frequency signals are therefore constrained to flow within a smaller cross sectional area of the conductor than the low frequency ones so that the effective cable resistance seen by the high frequency signals is greater than that seen by the low frequency signals.
Cable losses are therefore frequency dependent, with the high frequencies undergoing the most loss. This is known as the ‘skin effect.’ It causes a great deal of controversy in audio circles as many argue that it is only relevant at high frequencies which are beyond the range of human hearing. However, that’s not entirely true, because conductor resistance starts to increase due to the skin effect at around 20 kHz. It’s high frequencies which create timbre, ambience and a clear treble.
Effect of Dielectric Material on Velocity of Propagation (VOP)
High frequency signals occupy the periphery of a conductor (see above). Poor quality dielectrics (insulation materials) reduce the velocity of this signal, resulting in a sound which is biased towards the low and mid frequency regions of the audio spectrum. Thus, a poor quality sound often accompanies the use of a cable with a poor quality dielectric.
PVC (Poly Vinyl Chloride) is cheap to produce and, as such, is the most commonly used insulation in AV cables. However, PVC is the worst quality insulation a Hi-Fi or AV signal can encounter as its high loss causes a significant reduction in signal velocity. PVC is better suited to power cables and should be avoided in Hi-Fi and AV signal cables.
Other dielectrics in common use are Polyethylene, Polypropylene and Polytetrafluoride Epoxy (better known as PTFE (Teflon™) or Teflon,) and the new and unique Atlas (PTFE).
Teflon has a high melting point (327°C) – at the high temperatures involved, OFC and OCC revert back to the high-grain tough pitch state, destroying the integrity of the low grain or mono-crystal structures. But, over the last few years, Atlas has been researching ways of coating processed copper with Teflon, without the deleterious effects detailed above. Finally, after a great deal of research, we can now coat processed copper with a type of Teflon called Fluorinated Ethylene Propylene (FEP) – melting point 275°C – by cooling the copper during coating.
FEP allows the user to gain from the lower losses associated with this dielectric while still enjoying the benefits of low grain copper conductors.
Dielectrics.
Further research has led to the introduction of PTFE. The first Atlas products that introduce the new dielectric are the Mavros and Asimi interconnects and their matching speaker cables. PTFE (Teflon™) is a unique, low density dielectric material that offers significant performance improvements over solid PTFE (Teflon™) such as foamed polyethylene, PTFE (Teflon™) or PTFE. Thereafter other factors, which we can’t measure, influence quality.
Designs incorporating multiple insulated strands claim to overcome the problems of increased resistance due to the skin effect, but these low inductance designs tend to have higher capacitances. Low capacitance, low resistance cables will not affect the components they’re connecting as much as high capacitance cables can; speaker cables need to have lower resistance to avoid signal loss and interconnects need to exhibit low capacitance for improved signal velocity.
Sound systems which sound brighter than others within the audio range may be working on the verge of instability due to the use of high capacitance cables. Brightness is often mistaken for improved dynamics, but ‘improvements’ in the dynamic range should not be at the expense of low frequency information, as is the case when an amplifier becomes unstable. Undue brightness is also a feature of silver plated cables; these can become tiring to listeners over a period of time.
dielectric designs. PTFE (Teflon™) contains a higher percentage of air than solid PTFE; achieved by introducing small voids (less than one-half micron in diameter) of air within the material. The result is a lower dielectric constant of 1.5 to 1.3 (typically Teflon the next best dielectric is 2.1 to 2.3). The velocity of propagation is increased by typically 72% to 80% over ordinary cables and by about 30% over cables using standard Teflon dielectrics.
Greater Phase Stability = Lower Signal Deletions.
PTFE (Teflon™) has improved phase stability vs temperature variation because this is dependent upon the coefficient of thermal expansion of both the cable dielectric and conductors. Since PTFE (Teflon™) has a lower coefficient of thermal expansion than PTFE, the use of a microporous dielectric results in less dielectric expansion and so an improved phase vs temperature response.
For the same outer diameter, cables using PTFE (Teflon™) exhibit a lower loss of signal than those using solid PTFE. This is first, because the low dissipation factor of the dielectric itself reduces attenuation, especially at higher frequencies, and second the low dielectric constant of a microporous dielectric allows the use of a larger diameter conductor. With the Mavros speaker cable for example, better bass or low frequency information can be achieved with larger conductors and microporous PTFE.
The thermal expansion of solid PTFE (Teflon™) can have detrimental mechanical effects on cable because as the PTFE (Teflon™) expands with heat, it can decrease the air gap between the cable dielectric and connector contact, thus degrading termination impedance. But since the microporous dielectric expands minimally with heat, these effects are insignificant.
Tomi Engdahl says:
The insulating materials in the audio cables and the skin effect
https://www.polarisaudio.it/en/guide/audio-cables/the-insulating-materials-in-the-audio-cables-and-the-skin-effect
4.1 The Skin Effect
In order to understand the importance of the insulating material used in a hifi audio cable, we must first examine the distribution of alternating current within a conductor.
Different frequencies occupy different (radial) positions within the conductor. The low frequency signal occupies the central part of the conductor, while the high frequency signals are confined to the surface of the conductor. High-frequency signals are then forced to flow within a cross-section of the conductor’s cross-sectional area smaller than the low-frequency frequencies, so that the effective resistance of the cable, seen from the point of view of high-frequency signals, is greater than that seen from low-frequency signals. Cable losses are therefore frequency-dependent, with the high frequencies subject to greater loss.
This phenomenon is known as the “Skin Effect”. The subject is a source of considerable controversy in audiophile circles, where many argue that it is only relevant to those high frequencies that are already beyond the reach of human hearing. However, this is not entirely true, because the resistance of the conductor starts to increase, due to the skin effect, already around 20 kHz.
It’s the HIGH frequencies that create timbre, ambience and defined highs.
Extensive testing suggests that the conductor should have a cross-section of the transverse area between 3.00 and 4.5 mm/q in order to provide the maximum possible amount of clean bass frequencies. In addition, large cables should be constructed using a high quality dielectric configuration such as expanded polyethylene, PTFE or Microporous PTFE.
Projects using more insulated wires would claim to overcome the problems of increased resistance due to the skin effect, but these low inductance schemes tend to have a higher capacitance. Low capacitance and low resistance cables do not affect the components to which they are connected, as very capacitive cables do; speaker cables must have low resistance to avoid signal loss, while signal cables must have low capacity to improve signal transmission speed.
Amplification systems that sound brighter than others within the audio frequency range may actually work unsteadily, due to the use of particularly capacitive cables. Brightness is often mistaken for improved dynamics, but ‘improvements’ in dynamics should never be at the expense of low frequency information, such as when an amplifier becomes unstable.
4.4 Phase Stability – less signal cancellation.
Microporous PTFE has improved phase stability with respect to temperature variation, because this depends on the thermal expansion coefficient of both the cable dielectric and its conductors. Since Microporous PTFE has a lower thermal expansion coefficient than PTFE, the use of a microporous dielectric results in a lower dielectric expansion and therefore a better phase response with respect to temperature.
While maintaining the same external diameter, cables using Microporous PTFE show a lower signal loss compared to those using solid PTFE. This happens firstly because the low dissipation factor of the dielectric itself reduces attenuation, especially at higher frequencies, and secondly because the low dielectric constant of a microporous insulator allows the use of a larger diameter conductor.
Tomi Engdahl says:
Audible Significance and Engineering Minutia
https://www.audioholics.com/audio-video-cables/pear-cable-science/audible-significance-engineering
In reading documents provided by Pear Cables about what is considered important design parameters for speaker cable, one will see an exercise in hyping minutia with no proof that any of it is significant or even humanly audible. The worries of Pear Cable designers:
Litz geometry and Skin Effect
Exotic metals and internal corrosion
Cable dielectric absorption
Triboelectric effect
Internal mechanical vibration and resonance
Internal cable damping
Cable movement relative to connectors
Extreme tolerances on conductor length
Cable directionality
Cable break in
First, we will define what constitutes the boundary between the audible and the inaudible:
Listeners can detect a change in loudness when the signal is altered by about 1 dB (a 12% change in amplitude).
Steven W. Smith, Ph.D., The Scientist and Engineer’s Guide to Digital Signal Processing
A wide range of studies over the last century support 1dB as an average with the best result of 0.25 dB obtained only at inner ear resonance using wide band pink noise. Any sound outside of the commonly accepted 20 Hz to 20 kHz bounding frequency range of human hearing or any change in sound amplitude < 1 dB is inaudible.
The other important fact is that the ear is relatively insensitive to low and high frequency sounds.
A 20KHz harmonic note (because that's what it is) represents the 5th harmonic of the highest fundamental frequency on a concert grand piano, 4156Hz. Frequencies in this lofty realm can be heard by a very young, small percentage of the world's population. Typically this frequency will be over 20dB down from the fundamental which means that relatively close proximity to the reproducing system in a very quiet acoustical environment is required to hear these frequencies by the select few who have the capability.
As to phase and time delays:
A 5 microsecond delay has only been detected with any degree of certainty, under controlled laboratory conditions, within the approximate 3500Hz region where the ear is most sensitive. Again this detection must be in an extremely quiet environment, certainly below NC20, almost anechoic in fact.
A 5 ms delay is the upper bound limit for human hearing in optimal laboratory conditions, and only within the frequency range where the ear is naturally most sensitive.
Delays of up to 30-40 ms are combined by the ear in what is known as the Haas Effect, which is commonly used for sound reinforcement in PA systems, it allows stereo audio systems to recreate the illusion of a sound stage, and it is used as a basis for various matrix surround sound decoder schemes such as Dolby ProLogic.
So, what is the audible significance to the issues that Pear raises for audio cable design?
Pear boasts of a proprietary hybrid Coaxial/Litz geometry to prevent skin effect losses at audio frequencies, losses which are inaudible at mere fractions of a decibel.
According to Dr. Howard Johnson, attenuation of signal transfer through any copper wire can be broken into five distinct regions:
RC regionattn curve copper media
LC region
Skin-effect region
Dielectric loss region
Waveguide dispersion region
Skin effect is not a significant consideration until well into the megahertz frequency range and audio falls well within the RC range with attenuations of 0.001 to 0.08 dB/meter at 20 kHz.
At a frequency of 20 kHz (.02 MHz), the skin depth of a copper wire would be 0.47 mm, radially, meaning any wire of a 0.94 mm diameter or less would effectively have no skin effect.
Skin depth is larger than the radius of a 19 AWG (0.91 mm diameter) solid conductor and nearly that of an 18 AWG (1.02 mm diameter) solid conductor. Few, if any, audio cables are constructed from solid wire of this gauge or larger, meaning no significant skin effect. For frequencies lower than 20 kHz, skin depth increases and smaller wire increases the critical frequency before the wire cross section is not 100% effective. With skin depth increasing as frequency decreases, this effectively mitigates skin effect as an issue at audio frequencies.
Pear uses gold interconnect and OFC speaker cable conductors to eliminate internal surface corrosion, again related to skin effect.
The diffusion of oxygen, or other gases, through the insulation will be small, but the conductors will oxidize over time.
Most insulation jackets are effectively impermeable and any incidental oxidation results in copper oxide, an insulator.
Internal corrosion will not occur with a conductor properly encased in a dielectric.
What is also ironic is that gold is actually a worse conductor than either copper or silver, but is used by Pear to prevent cable corrosion that does not occur anyways.
Pear obsesses about dielectric absorption; another inaudible non-issue that causes high frequency losses an order of magnitude below established thresholds of human hearing and does not produce any measurable distortion between different materials and cable designs.
Pear claims internal cable components will undergo significant mechanical movement from acoustic and electromagnetic forces: minutia.
The bit about strength to prevent motion is a factual error in applying mechanics of materials. Mechanical strength is defined by the ability to resist load without material failure by a number of mechanisms including yielding, fracture, or rupture. The mechanical stiffness of a material, or its converse rigidity, or compliance in audio circles, is the ability to resist deformation caused by loads. This is a distinction introduced in every introductory class on engineering materials.
Pear cites significant Triboelectric Effect based on the supposed internal motion, the common source of static electricity from friction, an everyday occurrence when one, say, walks across carpet in socks on a cold, dry day. Triboelectric effect only occurs with kinetic friction, where one surface moves relative to another surface, not from static friction where no movement occurs.
Triboelectric effect can be a consideration in microphone wires where a performer’s movement with the cable may introduce localized bending stresses high enough to cause localized internal slip.
Any incidental movement of a speaker cable from acoustic vibration and electromagnetic fields will not be enough to overcome internal static friction between components in standard cable designs, staying well within the small deformation, geometrically linear range.
Static friction, in addition to any adhesion between the conductor and insulation, will generate enough force resistance to prevent movement: no movement, no work, and no triboelectric effect. So, unless one is running around carrying their speakers while listening to them, this is not a problem for speaker wire.
Pear then claims mechanical resonance at audio frequencies inside speaker cable.
The significance of mechanical resonance in audio cables can be dismissed with some simple common sense. Under conditions of resonance, energy that is input into a system by a frequency that is at or very near a natural mode or frequency of vibration will cause a disproportionate, unbounded increase in the amplitude of the movement. Considering the harmonic nature of music, if any resonant frequency within the audio band was energized it would repeatedly receive input energy, driving resonance and causing physical movement within the cable despite any internal dissipation mechanisms. A cable should then pulsate, which it does not by any detectable amount.
There will be no significant mechanical resonance in the cable components that will affect the audible output and electrical resonance does not occur until well into the LC region. Wires encased in their dielectric will not move by a significant amount from acoustic transmission, internal electromagnetic field action, or any other such phenomenon by a significant amount to be audible within scientifically established limits of human hearing.
Tomi Engdahl says:
The Genesis Report
https://www.qed.co.uk/qed-genesis-report
Contents
Download PDF Version
Introduction
The Cable’s Role
Basis of Assessment
Real Effects On System Performance
Skin Effect
Inductive Effects
Audibility of Phase Shift
Peaking Due to Inductance and Capacitance
Dielectrics
Cable Conductance
Effects of Capacitance
Capacitance Versus Inductance
Acoustic Crosstalk
Transient Performance
Cable – Induced Distortion
Multi – Strand Vs Single Core Distortion
Characteristic Impedance
Directionality
Conclusions
Genesis – The Outcome
Genesis – The Outcome
As summarised in (1,2,3,4 and 5) the most accurate and consistent- sounding loudspeaker cable will have minimal DC resistance, inductance and capacitance combined with low dielectric losses. All our research findings confirm this simple conclusion. Conductors designed with small cross- sectional are a in an attempt to avoid skin effect (which is not an issue anyway at audio frequencies) have higher DC resistance, with obvious harmful consequences.
Through Genesis, QED’s engineers have bucked the over- simplified ‘rule’ relating inductance to capacitance. Capacitance and dielectric losses have been reduced by choosing a suitable high-quality insulation material (low-density Polyethelene). In addition, minimising the insulation wall thickness and designing narrow webs (consistent with mechanical integrity) the ratio of air to solid dielectric has been improved, thus further reducing capacitance and dielectric losses. By optimally orientating multiple parallel stranded conductors, QED has been able to reduce both inductance and capacitance below that predicted from a single pair of the same DC resistance. The use of stranded conductors of good total cross section has kept DC resistance low. The result is a range of low-loss transparent – sounding loudspeaker cables of superior performance. The correlation between insulation and sound quality has also influenced the design of QED’s interconnects, which use foamed LDPE to increase the air/solid dielectric ratio and maximise sound quality.
Tomi Engdahl says:
https://www.qed.co.uk/qed-genesis-report
Directionality
Measurements to test for cable asymmetry in the samples, some of which were directionally marked by their manufacturer, revealed little to suggest the existence of directionality. Blind listening tests also revealed that listeners were unable to discriminate a cables direction. The lay of the cable, on the other hand, was found to have a measurable influence on performance, so to be reliable, any listening or measurement tests would require identical cable positioning for each direction.
Conclusions
Although there will always be those who remain sceptical about the importance of loudspeaker cables, the results of our research clearly indicate that system performance can be improved or degraded depending on the loudspeaker cable used. Analysing the compiled data revealed a fair degree of correlation between sound quality and measured performance.
Conclusions
Although there will always be those who remain sceptical about the importance of loudspeaker cables, the results of our research clearly indicate that system performance can be improved or degraded depending on the loudspeaker cable used. Analysing the compiled data revealed a fair degree of correlation between sound quality and measured performance.
The findings can be summarised as follows:
1. DC Resistance
Low cable resistance is of paramount importance if high sonic performance is to be attained, but this should not be achieved at the expense of other crucial parameters. High cable resistance results in several undesirable consequences: frequency response aberrations, impaired transient response, increased induced distortion and reduced inter-channel separation.
All cables exhibiting high resistance measured badly in these areas. Subjectively, their performance was highly dependent on the partnering loudspeakers. The forward midrange presented by these cables correlated closely with their subtly shaped frequency responses. High cable resistance also reduced dynamic impact with heavily scored music.
2. Inductance
Cable inductance is a prime cause of high-frequency attenuation and phase shift. Inductance causes impedance to rise with frequency, resulting in attenuation of the very upper frequency range at the speaker terminals and sometimes even peaking. In addition, inductance increases distortion at the loudspeaker terminals and degrades the loudspeaker’s overall transient response. So, low inductance is required to achieve a flat frequency and phase characteristic, low distortion and good transient response from the loudspeakers.
3. Skin Effect
Skin effect is shown to be of minor significance when considering cables of moderate cross sectional area. Cables with larger conductors, although exhibiting greater skin effect, also tend to be more inductive, which causes greater high-frequency signal loss.
Only at frequencies well above the audio range does skin effect increase to a point where it could be considered significant. Though the percentage rise in AC impedance of a high cross-sectional are a conductor will be greater than that of a low cross – sectional – area conductor, its effective AC impedance (and DC resistance) will still be lower. Skin effect also has the unexpected side effect of reducing the level of phase shift caused by cable inductance at high frequencies.
4. Insulation Quality
Dissipation factor proved to be a very strong indicator of sound quality. Most of the better sounding cables used superior dielectric materials: PVC insulated cables gave the worst sound quality. Cables which measured badly for dielectric loss appeared less able to reveal subtle detail, losing some of the atmosphere revealed by better cables with superior dielectrics.
5. Consistency of Performance
Loudspeaker cables interact both with amplifiers and loudspeakers. Consequently, some cables gave varied results in different systems. Those which performed most consistently were those with minimal inductance, capacitance and resistance. Unless an amplifier relies on inductance to maintain stability, keeping the speaker cables as short as practically possible optimises performance. High cable capacitance is best avoided, because it can result in amplifier instability, which can spoil sound quality and reduce amplifier reliability.
6. Directionality
Despite an increasing tendency for manufacturers to mark cables directionally, no evidence was found under controlled conditions to support the notion that speaker cables are directional. It was found, on the other hand, that merely laying a cable differently could affect the inductance and capacitance.
7. Solid Core vs Stranded Cables
Recently, solid-core conductors have increased in popularity on the basis that, if made thin enough, the solid conductor will show less variation in loss at high and low frequencies than a thicker stranded conductor. Our findings suggest that it is more likely to be the insulation and geometry of many solid- core cables which are responsible for their generally higher performance than stranded conductors. In any case, simply parallelling up conductors, whether solid or stranded, reduces inductance, which has a far greater influence than skin effect.
The stranded cables tested had higher inductance and leakage than many of their solid-core counterparts which generally used separately-insulated wires (giving lower inductance) with higher- quality dielectrics (giving lower leakage losses). No evidence was found to support the popular theory that stranded cables suffer from distortion due to diode effects between strands, so this seems to be something of a red herring.
8. Metallurgy
Electrical conductivity was slightly superior for cables utilising high purity copper (>99.99% pure). Greater improvements to conductivity were found with silver-plated copper and pure silver conductors. Generally, within this group of cables, the geometries and dielectric materials were more significant than conductor metallurgy in determining a cables sonic performance.
Tomi Engdahl says:
https://gearspace.com/board/connectors-cables-stands-and-accessories/996589-guitar-instrument-cables-star-quad.html
I was looking into some bulk cable to make some instrument cables, and came across a number of folks using Star Quad for this application. Am I wrong in thinking that’s not the best choice? If it does work well, how is it wired? All four conductors wired to tip, ground to sleeve? Half the conductors wired to sleeve with ground, half to tip? Just can that idea entirely?
On a similar note, the standard Mogami and Canare instrument cable is the same price for me. The Mogami claims to have a special conductive PVC layer under the shield that helps with microphonics, that the Canare doesn’t appear to have. Is it worthwhile to go with the Mogami stuff (which will likely be slightly more difficult to wire) or is it just marketing fluff?
Have only dealt with balanced cables thus far, so not sure what is best with instrument applications.
The big problem is that “instrument” is practically undefined. Whether star-quad (or any other kind of cable) is suitable depends almost entirely on the output impedance of the source. If the source is a vintage high-impedance, passive guitar pickup, then star-quad cable is probably not suitable, no matter how it is wired.
Passive guitar pickups. I’ll just stick with traditional instrument cable.
Using cables that aren’t instrument/guitar cables (i.e. coaxial design) will make a lot of extra work for you, different wiring strategies will give different capacitance etc. and the results may be less than optimal, particularly for passive guitar pickups.
Sommer designed and market their Colonel Incredible which has a non-coaxial design to be an ultra rugged instrument cable, but it has design considerations specifically for instrument signals and it also has quite a high capacitance as regards passive guitar pickups without buffering.
The secondary shields on coaxial instrument/guitar cables are not part of the Cable Fairy’s many snake oils and myth, they stop tribolectric microphonic handling noise. These need to be stripped back further than the signal wire insulation to avoid shorting.
The Canare GS-6 and smaller GS-4 do have the secondary carbon shields.
The main difference between coaxial instrument/guitar cables for practical tone/noise purposes is capacitance (partcularly high output impedance inductive guitar pickups, and especially single coils, regarding high end roll off and resonant frequency), main shielding type and density (spiral or braided), solid or blown PE conductor insulation (blown is less stiff with regard to handling), and a handful have let’s just say more ‘esoteric’ design considerations borrowed from the hi-fi world. Diameter is also a practical consideration for termination with pancakes and barrel jack plugs depending upon outlet specification, strain relief design etc.
List of pretty much all the bulk instrument/guitar cable capacitances for DIY here:
Guitar Cable Capacitance Chart
Hope this helps with your DIY instrument/guitar cable considerations.
Cheers,
I record my bassguitar using the high Z input of a mic pre, it is a trs wired input.
I noticed the connector in my bass was also a trs type but wired as a ts type.
So I made some changes to the wiring of the passive bass;
I started with sheilding all the cavity’s, connect that + the bridge to the sleeve.
The pickups + pots circuit connect to tip and ring.
By using an instrument cable ts only, the situation is the same as it was before.
I think the trs mic cable performs slightly better, it might be a capacitance thing, you remove a bunch of metal parts + strings from being connected to one side of the pickups… I don’t know if it is this, but I like the result (the cable is a Belden mic cable with trs jacks on it)
GUITAR CABLE CAPACITANCE CHART
http://www.shootoutguitarcables.com/guitar-cables-explained/capacitance-chart.html
Tomi Engdahl says:
Testing cables with a multimeter
https://en.customboards.fi/pages/7-testing-cables-with-a-multimeter
Tomi Engdahl says:
Building and Testing Audio Cables
https://community.element14.com/technologies/test-and-measurement/b/blog/posts/building-and-testing-audio-cables
What is wrong with Off-The-Shelf?
The cable I inspected did not have great shielding (proven through tests – see later) consisting of wire strands providing perhaps 30% (this is a guess) of coverage of the centre conductor.
In its favour, the cable outer insulation was very thick and maybe could withstand rough handling as long as the rough handling was no-where near the connectors
Furthermore it was a very low cost cable and probably would be adequate in a non-electrically-noisy environment. The connections would probably be fine if the cable was not mishandled.
What things would we want to see in good audio cable assemblies?
Everyone will have different requirements but from a general point of view these requirements would come out pretty high:
100% coverage shielded cables, grounded, to minimise capacitive pickup and RF pickup
Two and three cores for flexibility. The two-cored cable could be used for mono or stereo applications; for mono use one of the cores would provide the audio signal and the other core would be used for the ground connection. The shield would be grounded at one end. For stereo use, the three core cable could be used, and the shield would be used as the ground connection at one end. For balanced audio use (e.g. with XLR connectors) then again either cable could be used.
Ideally a controlled pair cable for balanced audio applications, to reduce the effects of as many modes of noise pickup as possible
To provide protection from interference at low frequencies the best practice is to have the shield connected only at one end. When we hear mobile phone pickup on audio circuits, this is actually low frequency interference components that we are hearing. However we also want to minimise high frequency pickup up to about a few MHz just in case it mixes with signals in electronics. There is a ‘hybrid grounding scheme’ discussed in an Analog Devices paper (PDF) where one end has a capacitor to ground. Any ceramic 100nF capacitor would work admirably. A large ferrite may be slightly effective too but unlikely; the input impedance of audio circuits is far higher than the impedance from the ferrite and we might obtain less than a dB of benefit at best, and at audio frequencies there would be no benefit, it would just be a weight on the end of the cable. But worth experimenting with if there are issues caused by high frequency (of the order of MHz or higher) signals.
INTRODUCTION TO ELECTROMAGNETIC COMPATIBILITY (EMC)
http://www.analog.com/media/en/training-seminars/tutorials/MT-095.pdf
Tomi Engdahl says:
MEASUREMENTS: Archimago’s Colorful Speaker Cables, KnuKonceptz, AmazonBasics, and “freebie” speaker cable. (And changes at Audiophile Style.)
http://archimago.blogspot.com/2020/02/measurements-archimagos-colorful.html
I suspect every audiophile regardless of “objective” or “subjective” leaning would agree that “The best speaker cable is no speaker cable!”. That is, perfect transparency would be a direct connection between amplifier to speakers with no opportunity for a cable to introduce any potential power loss, change frequency response or time-domain characteristics of the signal. Alas, nothing’s perfect, we do need cables in the real world, and as a result, we do have to consider the electrical properties. As I’m sure you’ve seen many times before, the basic schematic for a cable can be laid out like this – Rs = series resistance, Ls = series inductance, Cp = parallel shunt capacitance:
Remember that this the “lumped-element” circuit and if we want to be even more accurate, we could view the cable as countless little series resistors and inductors plus parallel capacitors. Depending on the overall strength of those 3 parameters, the cable can act to impede the voltage to our speakers (signal loss) or act as a type of very weak filter that can subtly change frequency and phase response of the AC signal.
Having said this, using the example of the DIY cable, let’s measure it to provide a practical example. What’s needed is an “LCR meter” with adequate precision since we will be looking at milliohms, microhenries, and picofarads!
It’s rather convenient measuring speaker cables terminated with banana plugs as one could just plug the cables directly in to get the reading. Just make sure to calibrate first with the shorting procedure.
Like many LCR meters these days, this one can give me results at various AC frequencies – 100/120/1k/10k/100kHz. For audio work, it would be nice to have had a 20kHz reading but this is just fine and the reading at 10kHz should be very close to what we would see at 20kHz.
Let’s face it, the audio Industry will always bias towards subjectivity because it prefers to deal in “opinions” and conclusions can always be steered towards “go listen for yourself” – which these days typically means putting money down, dealing with shipping, and the hassles of a return possibly. The only discipline asked of its consumers from the Industry is a habitual desire to upgrade. Likewise the Industry is threatened by systematic evidence because they would rather provide the information straight from their Gurus and through highly questionable whitepapers with no corrective feedback mechanism.
Yes, a subjective perspective is easier to deal with, it’s less emotionally taxing. Nobody wants to be told one is wrong using factual evidence these days, right? Not just audiophilia, but it seems to me that in many areas of public discourse, having “fun”, accepting claims of “lived experience” no matter how ridiculous, is more important than education, understanding, and appreciating what is truth.
Remember the outcomes of intolerant subjectivism as we’ve seen with Michael Lavorgna’s first iteration of AudioStream. Look what happened to the once-vibrant InnerFidelity without Tyll’s objective analysis.
Tomi Engdahl says:
The Genesis Report
https://www.qed.co.uk/qed-genesis-report
Tomi Engdahl says:
Best audiophile cables: Fact and fiction explained
Would expensive cables improve your swanky new headphones or speakers?
https://www.soundguys.com/best-audiophile-cables-21871/
You’ve just bought a swanky new pair of expensive headphones or speakers, but how to make the most of them? Various guides and conventional audiophile “wisdom” might point you down the road of improving the rest of your setup, right down to the cables and wires that connect things together. You might also find quite a few audiophiles who advocate for splashing hundreds of dollars on cables to get the most out of your fancy new setup.
But before you even begin down this path, you need to look at the specifics of your setup. Most importantly, is your cable carrying a signal to an active or passive component? Speaker wires that need to carry power from an amplifier need to be selected a little more carefully than a short “aux” cable for your car.
Editor’s note: this article was updated on May 18, 2021, to clarify points about the “skin effect.”
What to look for in the best audiophile cables?
Low impedance is the key factor of a good quality audio cable, particularly when it comes to speakers and low impedance headphones. Signal loss and filtering can occur if your cable offers a lot of electronic resistance, and particularly when that resistance changes with frequency (impedance). This is usually the case with speakers and headphone drivers.
I won’t bore you with the physics, but essentially a higher source impedance (driver output + wire) reduces the amount of power that reaches the headphones or speakers. Furthermore, speakers and headphone drivers are reactive loads, which means their resistances vary with frequency. As an example, a pair of headphones might have a higher impedance at high frequencies, which would produce an additional loss if you added a high impedance cable in series.
Should you buy expensive audiophile cables?
Ultimately, all you need from a good quality speaker cable is low resistance, capacitance, and inductance. That’s quite simple for manufacturers to produce without any unnecessary alchemy. If you know where to look, you can find inexpensive cables with the desired basic specifications listed.
If not, you can follow the general rule of thumb that 12 or 14 gauge speaker wire is needed for long wire runs with low-impedance speakers (4 or 6Ω). Meanwhile, 16 gauge wire is fine for runs under 50 feet to 8Ω speakers. For headphones and short connections to active speakers, essentially any cable will do as the power transfer is much lower.
Great-sounding audio cables don’t have to be expensive.
Debunking myths about audio cables
Save yourself some money: in audio, “basic cable” is a good thing.
https://www.soundguys.com/debunking-myths-about-audio-cables-13093/
Analog cable myths
Now, it is true that back in the day, cheaper cables were made with less-than-ideal components and had fairly poor quality control. When Monster cables hit the scene, people loved to bash how much they cost, but you did get a somewhat decent build quality to them for the investment, along with a lifetime warranty. But that was a long time ago, and nowadays you can get cables for dirt cheap that not only perform their function almost perfectly, but will also stand up to the test of time.
The argument for audiophile cables basically follows this logic:
The cable’s task is to carry an analog electrical signal from the source (or amp) to your speakers.
The cable is made of materials that present impedance (resistance and capacitance).
In doing so, the cable affects the signal that reaches the speakers.
Now, this is true (to some degree). However, for headphones, that degree is small enough that you can safely ignore it—despite colorful online arguments about it. If you’ve read our article on amplifiers, you’ll know that the easiest way to properly power something is either to lower the resistance or increase the power. Narrow wires will have more resistance, so if you need a lot of juice or you want a 20+ foot cable, it’s possible you could do with thicker cables. But since headphones require a comparatively tiny amount of current compared to bookshelf speakers, the same logic follows for how thick their wires need to be. Manufacturers aren’t bad at their jobs, and they definitely won’t skimp on any component that determines how good their product sounds, so the included cables are generally pretty good for your equipment—it’d be bad for business if they weren’t.
Higher quality materials will also rarely make a big difference—you could even use a coathanger as a speaker wire in a pinch. Using gold and palladium for their high conductivity ratings sounds nice, but you’re not getting double the cable quality for double the price: you’re just paying extra money for a luxury of debatable merit. So when someone tries to sell you ridiculously priced cables, be sure to laugh in their face. Your money would be much better spent on more useful things.
Really, the biggest thing you should worry about is whether or not your cables are properly shielded. However, that’s another problem that’s extremely rare nowadays, and unless you’re buying some no-name penny-cable from a bin somewhere, you won’t need to worry about it. If you are having interference issues, you can try moving your cables away from common sources of electromagnetic (EM) interference, such as your computer, router, etc. If that doesn’t work, then it’s time to consider better cables.
Digital cable myths
So that covers analog cables, but what about digital? The previous logic doesn’t hold up at all. These damn things carry ones and zeros: while you might need a powered USB hub to get a signal over long distances, these cables either work or they don’t. Errors are massive and readily noticeable—and when those happen just get another cheap cable. Whether you’re transmitting video or audio, the same is true. For example, systems that use HDMI will cut out your video if it detects problems, as that’s how the encoding works.
Wrapping up
Now, there’s plenty of first-hand user testimony about audiophile cables—analog and digital—improving experiences. However, that’s another grumpy article for another time: psychoacoustics is a whole different ball o’ wax, and tackling confirmation bias and other common problems is going to result in hurt feelings.
What I want you to take away from this article is that you shouldn’t feel pressured to spend a ton of money on cables if you aren’t sure you need them. Ask for a layman’s explanation at your local shop if you’re on the fence, and if your salesperson can’t give you one without any flowery unquantifiable adjectives: Walk away.
Tomi Engdahl says:
How to hide the wires for your speakers and TVs
In-wall wiring guide for home A/V
https://www.crutchfield.com/S-6YkkNY81D6q/learn/learningcenter/home/inwall_wiring.html
This guide will help you save money by doing your own small-scale in-wall wiring projects in both finished and unfinished rooms. If you decide to hire a professional, the knowledge you gain will help you work through the process with your contractor.
Can you do the in-wall wiring yourself?
Is it legal?
In most locales, a homeowner is allowed to install low-voltage wiring. However, each state has its own code, as do some cities and counties, so check with your local authorities to be sure.
Tomi Engdahl says:
Audiotechniek
Cables and the Amplifier/Speaker Interface
https://www.opusklassiek.nl/audiotechniek/cables.htm
Introduction
Loudspeakers seem to be connected to power amplifiers with greatly varying degrees of care. The professional generally selects wiring of appropriate size and type for the given application, while many others are quite casual about such matters. Recently, however, considerable attention has been drawn to the issue of loudspeaker cables by the appearance of numerous ‘special’ cables with properties that allegedly improve the quality of the sound delivered by the loudspeaker. While most of these claims are no more than pure fantasy, there is just enough edge of truth showing to make a hard look at loudspeaker cables seem appropriate.
In this article, loudspeaker cables are investigated to determine whether or not their transmission line behaviour is significant for audio frequencies. Conclusions are reached regarding the validity of lumped equivalent representations of short transmission lines. Certain critical frequencies are calculated and measured to estimate the effect that the cable will have on the amplifier and the loudspeaker load. The problems caused by the resistance of the crossover, level pads, and any fuses in the circuit are considered briefly.
Cable Parameters
The parameters which describe the cable electrically are series resistance, series inductance, shunt conductance, and shunt capacitance. These parameters can be determined by direct measurement and/or by calculation from elementary formulas. They depend entirely on the geometry of the cable and the nature of the conductors and the insulation used.
Conductors of copper, silver, or similar high-conductivity materials – regardless of the method of drawing the wire – behave similarly. The electrical properties of cables are not significantly affected, at audio frequencies, by the type of insulation used. The mechanical properties of the cable, however, may be more desirable with use of certain insulators and construction techniques.
Note that the larger the physical size of the wire, the smaller its gauge number, and that each change of three wire gauge sizes doubles or halves the wire’s cross-sectional area. The nature of the insulation, and whether or not the wire is ‘tinned’ have little effect on the electrical parameters of the cable at audio frequencies.
Present-day cables that deviate fro the techniques used to construct cables in 1979 usually use fine strands of wire which are gathered or braided in a variety of complex geometries. Some of these techniques increase and decrease the series inductance of the cable slightly. Both techniques, increasing and decreasing inductance, are claimed to improve the electrical properties of the cables. In the following discussion, it should be apparent that neither of these techniques makes much difference at audio frequencies.
Tomi Engdahl says:
http://www.westpennwire.com1
Audio Design
Audio Systems
Line Level Audio
Wireless Audio
https://www.westpennwire.com/pdf/16774-Audio-ProductGuide.pdf
Tomi Engdahl says:
A Guide to Quality Cables
https://bambachcables.com.au/a-guide-to-quality-cables/
We use cable every day in our lives more than you may realise. It carries power to our computers and phones, helps kick start our cars in the mornings and of course lights up our homes. If there is a disruption in the supply of power or signals it can be inconvenient or dangerous.
Conductor Centre
It is a requirement to have a minimum radial thickness of insulation and sheath on the conductor or cable. The amount required is governed by various factors such as insulation type and voltage. If the conductor is off centre, the insulation thickness may be below the minimum threshold. If the insulation thickness is too thin, it can break down during operation and cause a fault or arc. For instrumentation and signal cable, an off centre conductor will increase unbalanced capacitance and degrade signal quality. The same principle applies to the sheath thickness.
To apply a quick check, square cut a cable length and inspect the cable. If the insulation and sheath looks fairly evenly distributed around the conductor or cable, then it should be ok. If there is a noticeably thin and thick section, there could be an issue.
Conductor Area
Conductor area is important to carry the minimum continuous current and provide suitable maximum voltage drop. The associated conductor size for current ratings and voltage drops can be found in AS3008.1.1. If there are a few strands missing from the conductor, this will reduce the CSA (conductor surface area) and increase resistance. If a 2.5mm² conductor carries the same continuous current with reduced CSA, it will be operating at a higher temperature. If the cable is carrying the maximum prescribed current, then the temperature will be higher than the rating of the insulation. If this is the case, the insulation will degrade quicker and could actually melt away, exposing the conductors.
Reduced CSA’s also have an effect on the voltage drop and power consumption. The voltage drop is proportional to the resistance, so a 2.5mm² carrying 20A at 240V has a voltage drop of 5% at 33.3m. If the conductor resistance is increased by 10%, the voltage drop at 33.3m will be 5.5%.
Insulation Resistance and Core Continuity
Conductors are insulated so that they can be protected from each other. There can be faults when there are fluctuations or holes in the insulation. If the cable has a shield or braid, it is more likely that there will be continuity between the braid and core rather than core and core. It is also important that the cores and shield have continuous continuity through out the run. Cable can be supplied with joins buried in the reel. Cable continuity can is an issue where the join only becomes obvious after the cable has been reeled off the drum,
To check that there is no continuity between the cores and shield, use a Megger Resistance Tester to check the resistance value. The test can be carried out in various ways such as core-core, core – all cores or core – screen. The longer the length of cable, the lower the resistance value will be. Different insulation materials will also have different dielectric strengths. As a guide, the resistance value should be in the 10’s of MΩ to GΩ. Continuity of cores can be checked using the Megger Resistance Tester or a multimeter. In this instance, the desired resistance value is low. Once again the value found is length dependant. As a guide, if the resistance value is in the MΩ, there will probably be an issue.
General Feel and Appearance
There is measuring and testing that can be done on cable to determine its quality but a simple general inspection is all that could be needed. Cables are generally intended to be round however they can end up ropey, snakey and odd shaped. An un-round cable could cause issues when terminating through a gland. The material can be checked by the general feel of the cable. By rubbing or cutting the material, it can give indication of the quality. For example, poor quality silicone is very soft and when rubbed, it wears away. Like anything you buy, you can get a good sense of the quality just by having it in your hands.
Tomi Engdahl says:
Cableloss Calculator
https://products.electrovoice.com/na/en/cableloss/
Tomi Engdahl says:
DIY speaker wire: does insulation matter?
https://forum.audiogon.com/discussions/diy-speaker-wire-does-insulation-matter
I’m planning to make solid core copper speaker wires and have a couple of options as to the insulation to use, and would like your input: cotton, mylar, Nomex, or mica-based.
Does the insulation material matter?
How thick should the insulation be?
BTW, what kind of voltage are speaker wires subject to?
Looking into Anti-cables, they use VERY thin PVC, I believe.
How close together? Should I twist the pair? Anti-cables are suggested to be twisted at 3 to 4 twists per foot.
Cotton is a terrible suggestion as a dielectric for a copper conductor. Untreated cotton will absorb moisture from the atmosphere and allow unabated access of the atmosphere to the conductor. In the form that you will be using it in it’s dc is a min. 3.9 a bit higher then PVC (not good for this app.)BTW I believe anti-cables use a polyester varnish like magnet wire not PVC.
The only thing cotton has going for it is that it reduces vibrations that is why it is used as a filler not an insulation.
Try something with teflon…
http://www.takefiveaudio.com/mall/shopdisplaycategories.asp?id=8&cat=Cable%2FWire
I tried Anti-Cables twisted and not…. I untwisted them for a more open and effortless sound.
I’m with Al it should not matter enough to worry about. As some have mentioned wire geometry can have a small effect – especially placing wires far far apart (best place them close together). Twisting wires is most important for small signals into high impedances or for signals lines passing through very noisy RM/RF environments – I should not think it matters for speaker cables.
However, solid core versus stranded is probably not enough to worry about either (other than teh stiffness may cause connection integrity problems at each end). So I guess this makes a full circle – it must all be critical!!
From what you have written it seems that you are planning to use a un-insulated wire that you have and insulate it.
Not a good idea. First there is already a layer of oxidation on the copper if it is un-insulated, second whatever you put on most likely will not be air tight, third it is not the safest idea.
Get 14awg teflon insulated OCC wire, try 8-10 twist per foot, solder on some spades with some silver bearing solder…
BTW mylar DC is between 2.8-3.7 for cable passing a signal you shooting for low DC…
By “dc” CPK meant “dielectric constant,” which is proportional to the capacitance the cable will have, and the amount of “dielectric absorption.” Thicker insulation will also increase capacitance, everything else being equal, and thinner insulation will reduce it.
My own feeling is that as long as it is within reasonable limits capacitance in an 8 foot speaker cable is not especially critical. It would be more important in an interconnect cable, because of the much higher output impedance of the component driving the cable. The opinions of others may differ on this, and I readily acknowledge that other factors, known or unknown, might in some systems make capacitance more important than I am envisioning.
Am I looking for a lower or a higher DC? Mylar is 2.8 to 3.7…is that good??
That’s magnet wire, it should be enameled, just use it as is, you are good to go. As for dc < 2 is good.
Tomi Engdahl says:
Measured differences between interconnect cables
https://www.audiosciencereview.com/forum/index.php?threads/measured-differences-between-interconnect-cables.37661/
Presented purely for interest.
TLDR:
1) Differences in cables exist and can be measured at the audio level and achieve statistically significant differences
2) The differences are vanishingly small, so it doesn’t make sense when listening to audio
3) The differences may make a difference when measuring gear
4) These tests will be repeated when my E1DA Cosmos Grade-A unit arrives later this week.
I’m going to tell the whole story and the process I took.
100% cables are a waste of money for audiophile tweaks. :).
This is a clear example of something measurable but not actually important.
Tomi Engdahl says:
I have four speaker cables here and they all sound different!
https://www.audiosciencereview.com/forum/index.php?threads/i-have-four-speaker-cables-here-and-they-all-sound-different.35850/
To the OP – I hear you, but I’m these days firmly of the belief that what we hear we can measure and there’s no ‘hidden thing’ which cannot be measured…
You didn’t give details of your amp and speakers – that’d be handy. A list of a couple of tracks you heard the difference easiest would help too.
Some amps do react to different levels of capacitance and inductance in cables (it’s an amp design issue I feel if they’re not unconditionally stable with the bodge that the cables provide the final inductance). Other amps, usually transformer coupled valve amps but the Croft hybrids are similar, offer high output impedance which equalises the passive speakers they’re driving – just maybe, different speaker cables will affect this further? – I’m guessing but it’s a faint possibility.
Copper covered aluminium cables add gobs of extra resistance for the same gauge over standard copper types.
Lastly, the gauge of the cables themselves is all telling. I used to sell plenty of a silver plated cable (with necessary PTFE outer). With a mid to high level UK based system, it livened the sound up nicely but with a proper higher end system, it sounded scrappy and crude. Back then it didn’t ‘click’ with me that the gauge of this quite pricy stuff was little better than the generic 42 strand cable we gave away with cheap mini systems!!!!! We’d never dream of using the give-away 42 strand cables with more ‘exalted’ systems, but I regret not doing an A-B comparison at the time.
For ten feet runs and with my now tatty-with-age dealer hat on, I’d suggest a simple 2.5mm copper stranded cable (in the UK, Kabeldirect and Fisual do something suitable at fair prices) and regard that as a kind of reference for shortish runs up to several metres each side -
You forgot to mention which amp was used and which speakers.
How the ‘blind test’ was performed and controlled.
Differences in separation is a tall order as cables are always separated anyway.
Only some info about pricing and as we all know price says very little and your credentials which none can verify.
To summarize: For such tests, you need controled double blind methodology. If not, you are deluding yourself. However, what we already know is that decent cables should not and do not demonstrate any sonic differences, and that decent cables at domestic lengths can be dirt cheap. If there are differences in a double blind controlled test, it means a cable is a bad one, and that can be measured. See here for more: http://archimago.blogspot.com/2015/06/musings-audio-cables-summary-non.html
Ok. I already knew that folks here believe that there are no audible differences between cables.
I didn’t come on here for a debate. That is boring and a waste of my time.
I thought I’d ask how one could explain these things.
A few things -
To someone telling me I didn’t do something I know that I did, I have no response other than – I am not interested in proving anything to anyone. If you don’t believe me, wonderful. No need for your input as there is nowhere to go from there.
If this is not going to be a pleasant exchange, I’ll just quit the site now. I did not join to argue or debate.
I asked some questions and if these questions are beyond what anyone here can fathom, then perhaps I am in the wrong place after all.
I didn’t come on here to prove whether or not I heard something.
I asked if anyone had any idea what is causing the differences.
If you do not believe it is possible, then there is no need to respond. Again, that would be a waste of time.
Some of the wires had noticeably more bass
This would be very measurable though (one of the aspects you mention that actually IS verifiable)
That could be caused by the cables having an unusually high resistance which in your case is extremely unlikely.
You asked for explanations. There aren’t any. That is……. not a scientific one and as none of the tests were verified using measurements and test controls ‘we’ will chalk it up to subjective impressions.
Only some very exotic cables with extremely high capacitance might make some amps unstable (without the obligated inductors being used that will be supplied) but not all amps.
Copper, silver, unobtanium are all behaving linear in and well above and beyond the audible range in the same way so cannot change tonality (more bass etc).
So when you perceived that you should verify by measuring. Subjective evaluations are just that.
In any case.. in the end.. all that matters is your enjoyment.
When 1 type of cable does this for you audibly so and you tested only 6 then, most likely, you could maybe get more ‘improvements’ with other cables. That must be bothering you in the back of your mind as all cables you tested were different they all should do so ?
You did not describe the listening test methodology, and that is where I would look for the explanation of what you heard. So:
1 It needs to be exactly level matched, and you need a volt meter for that, to achieve a better than 0.2 dB result.
2 Changeover has to be very quick, i.e. near instantaneous, given the short duration of human hearing memory.
3 And of course the interpretation has to be statistically solid, with enough observations and a big enough difference to be confident that the result is not random.
4 You have to use a good solid state amplifier without any weird behaviour. No Prima Luna tubes or Naim.
If, after all of this, the hypothesis of differences still stands, then we need measurements to explain them.
Willem said:
You did not describe the listening test methodology, and that is where I would look for the explanation of what you heard. So:
1 It needs to be exactly level matched, and you need a volt meter for that, to achieve a better than 0.2 dB result.
2 Changeover has to be very quick, i.e. near instantaneous, given the short duration of human hearing memory.
3 And of course the interpretation has to be statistically solid, with enough observations and a big enough difference to be confident that the result is not random.
4 You have to use a good solid state amplifier without any weird behaviour. No Prima Luna tubes or Naim.
If, after all of this, the hypothesis of differences still stands, then we need measurements to explain them.
Actually used some very good meters on all equipment prior to testing and verified my tests and results with an engineer live over Skype.
changeover was very quick. Also did long-term listening tests as well to compare against each other.
Everything was tested on solid state. Left my tube amps on the side for this.
The results were anything but random.
But again, I did not describe EVERYTHING in my initial post because I thought this would be more a conversation and not an interrogation.
I am only replying now because you took the time to write a thoughtful reply, so I am answering. But really, I have completely lost interest as this is not a discussion. It is a bunch of people believing something and entering into it with their bias. Instead of discussing an experience and perhaps sharing some information which may be able to explain the difference.
I could say much more, but I really don’t enjoy these kinds of debates.
Well, you can ask to have the cables measured but…
Amir has already measured speaker cables. He even has one lying around for 2 years now from a manufacturer who (sadly) is no longer with us.
There are some issues with measuring cables.
A: it is not done on various speakers/loads and needs to be to evaluate properly. Just 4ohm resistive can only give so much info.
B: it is not done with the same amp as yours.
C: why would 3m be a good length ? Some prefer shorter and some need longer cables.
D: Amir can take some measurements with the AP (under various loads) and they will show some minor differences (very time consuming).
E: One can measure L, C, R and these numbers will differ. Whether or not this could (potentially) matter depends on load and amp.
F: Fully characterizing 6 cables AND doing proper controlled blind tests will take days/weeks. Time that could be spent on more worthwhile things.
I can understand you feel your findings are dismissed. When you read some cable threads (there are many) you could have known what the reaction would be.
People here want to see all aspects and measurements and confirmed listening tests that could pass scrutiny.
Tomi Engdahl says:
A Guide to Audio Cabling
https://nicab.co.uk/a-guide-to-audio-cabling/
Tomi Engdahl says:
Audio Interconnect Comparisons
https://sound-au.com/articles/cable-compare.html
Conclusion
I have clearly shown that no interlink cable is equal. Identical cables yield identical measurement results, yet different cables yield different results. However, the non-linear distortion measurements suggest that the cables behave very similarly where it is important, although the numbers are not 100% conclusive.
Then the tests that actually tell a story and why I decided to do this experiment: actual audibility. In all recording examples, a very slight high frequency component can be heard. This is mostly due to the fact that the device’s rejection reduces with increasing frequency.
In my opinion, it would be a huge stretch to say that any of these cables have a significant aural impact on the signal quality. The recorded differences are very small and they sound about the same for each type of cable. What we can conclude with a high degree of certainty (because of the high rejection ratio at bass frequencies) is that there is no difference in bass performance. None of the recordings show any kind of low frequency residual. So any review of a cable claiming more ‘bass authority’ or some such thing is unlikely to be true.
I wish I had all the cables in the world to test with, but that would be kind of an expensive enterprise. I hereby challenge any cable manufacturer to give or lend me a cable to put to the test. I also encourage people to repeat this experiment; all designs are available.
I already have future plans for a second version of this article: it’s very simple to increase the rejection ratio by increasing the INA128s gain. I will try to obtain more cables to test and make recordings with an improved version of the difference amplifier.
Tomi Engdahl says:
Audio Interconnect Cables
It’s really quite simple, just not that easy to explain
https://www.lessloss.com/docs/high-end-audio-interconnect-cable.pdf
It is the goal of this paper to show that the
Tunnelbridge™ design addresses and obliterates
the most fundamental sound quality loss sources
within audio interconnects, and to show how this
is achieved.
If we model an interconnect as a set of lumped pa-
rameters [1] (in other words, a low pass filter), the
equivalent schematic of such a cable connected to
the audio gear looks like this
Because the resistance of the cable itself is so much
smaller than the output and input resistances of the
gear, we choose to discount this resistance of active
loss, and we simply add it to the gear’s resistance
(i.e. the electrical resistance of a cable is many orders
of magnitude smaller than the normal dispersion of
100k Ohm resistors incurred during manufacturing,
which, in the best of cases, are manufactured to only
a +/- 1% tolerance of accuracy, and nobody hears or
can hear this amount of deviation).
The bandwidth of such a schematic, influenced by
its capacitance C, is equal to f=1/2πroutC. And, influ-
enced by its inductance L, is equal to f=Rin/2πL. Sup-
posing a typical cable capacitance value of C=100pF
and rout =100 Ohm, then f, the bandwidth passed by
the cable, is about 15 MHz. Therefore, any typical
cable, according to this model, should pass an audio
signal from component to component without any
noticeable frequency distortion.
However, if we consider a cable as a distributed se-
ries of small inductances and capacitances, which is
what it in fact is because it has a length, the more
accurate equivalent schematic now looks like this
If we connect such a cable into a system whose
source and receiver were both also of this equal
impedance, we would have a matched [3] line, in
which we would not perceive distortion of fre-
quency response nor of impulse response. How-
ever, there is no official standard of implementing
matched lines in home audio applications. As a
rule, the output impedance is made to be low, and
the lower the better. The input impedance is made
to be high, and often times, the higher the bet-
ter. The aim of this is to create the best conditions
for the first model we mentioned above, as a set
of lumped elements. That model is insufficient to
explain the design merits of true high performance
audio interconnects. In other words, you can still
hear the difference between cables.
In a transmission line model, the source signal is
introduced into the input end of the cable, and the
other end is said to be “open.” This represents, in ef-
fect, a quarter wave resonator ( /4) or stub [4]. It is
often overlooked that this creates a very profound
resonance at the frequency whose wavelength is
about four times as long as the length of the cable.
For example, if the cable is 1m in length, this large
resonance will be around 75 MHz
One other aspect which is often overlooked when
describing the effect of an interconnect cable on
sound quality is the spontaneous electric polariza-
tion or “memory effect” of the dielectric material
situated in the electric field within the cable [5].
This effect is often taken into consideration when
investigating the influence of capacitors on sound
quality.
First, charge an electrolytic capacitor, then fully dis-
charge it by shorting its two leads for a few seconds.
Unshort the capacitor and then quickly measure the
voltage across the capacitor. What you’ll see is that
the voltage is at first zero, and then quickly begins to
rise. The capacitor seems to “remember” that it was
recently charged. Of course, a good capacitor should
not exhibit such behavior.
Detailed studies have shown that this effect is not
limited specifically to electrolytic capacitors. Any ca-
pacitor whose dielectric material’s dielectric constant
is substantially larger than 1 portrays this effect,
and, as it turns out, the larger the dielectric constant
and, therefore, the larger the electric field inside the
capacitor, the greater this memory effect [6].
Because
a cable is in this regard a capacitor (simply unrolled),
the same holds for loss of signal quality in cables.
When the signal is no longer present at the cable
source, it can “show up” somewhere in the cable at a
later time. It is no wonder, then, that manufacturers
of high quality cables emphasize the importance of
the quality of the chosen dielectric material.
The Tunnelbridge secret
is that there is no secret.
The architecture is that of a coaxial cable with two
concentric shields. The signal is fed into the cent-
er conductor and the outer shield is the “ground”.
The middle shield receives the same signal as the
center conductor through a voltage unity gain
buffer amplifier. The buffer’s function is to protect
the signal in the center conductor from loss and
distortion arising from capacitance between itself
and the outer shield. Because there is never any
potential between the center conductor and the
middle shield, there is also no electric field there.
If there is no field, there is no capacitance; nor is
there any spontaneous dielectric polarization. Thus,
we have tackled the “memory effect.” The signal,
without having been exposed to the electric field,
now makes its way through the cable into the input
socket of your destination gear.
We experimented with this concept and heard clear-
ly that it works very well. Then we took it one step
further. Where we first obliterated the capacitance
of the center conductor to the ground by compen-
sating the electric field there, we now managed to
compensate the center conductor’s magnetic field as
well. This aspect of our final design was the most
difficult to achieve. As a result, the center conductor
now has no magnetic field, which means that it also
has no inductance.
After many experiments with electromagnetic field
simulation software, real cable models, and much
audiophile gear, the results achieved surpassed our
wildest expectations. It turned out that our theoreti-
cal model proves itself in practice. There was an ob-
vious difference in sound quality when comparing
the Tunnelbridge™ with traditional interconnect
cables made with identical materials. When a ca-
ble’s dielectric is not influenced by both the electric
and magnetic fields, its behavior is electromagnetic
neutrality, meaning non-influential to the signal in
the center conductor, which never experiences ca-
pacitance or inductance in this design.
Ooo. Electronics. Scaaary.
Isn’t a cable supposed to be completely passive?
How about the dangers to pristine sound quality
brought forth by the inclusion of active schematics
in the Tunnelbridge?
There is no direct influence, because the signal
which reaches the input of your gear never encoun-
ters the circuitry in the Tunnelbridge™. And the
signal in the Tunnelbridge™ which does encounter
this circuitry never makes its way into your gear. The
only function of the circuitry is to obliterate both
the cable’s capacitance and inductance which would
normally affect the signal.
Let’s put some numbers on it. If, for example, the
Tunnelbridge™ electronics would cause a 0.01%
distortion of the powered Tunnelbridge™ signal,
then it would not cause a 0.01% distortion of the
system; it would only cause a 0.01% rise in capaci-
tance and inductance in the cable when compared
to no cable at all.
Tomi Engdahl says:
MUSINGS: Audio Cables Summary, Non-Utilitarian Functions & Scientific Falsifiability
https://archimago.blogspot.com/2015/06/musings-audio-cables-summary-non.html
The bottom line is that with cables of reasonable cost, construction, and ultimately of typical electrical parameters, I have found no evidence of audible qualitative difference (objectively or in my personal subjective evaluation). Despite claims on the Internet, I have also not been able to find anyone I know (wife, kids, family, audio friends) able to differentiate cables even when they start off with strong beliefs in the matter.
The lack of objective difference between cables despite the huge price variability makes cables one of the least cost-effective options for bettering one’s high-fidelity system beyond the approximate price levels above in my opinion.
If one accepts the above conclusions, are there reasons why an audiophile would still spend hundred if not thousands on a fancy set of cables? Well, there are the non-utilitarian functions. Basically, “functions” attached with luxury goods in general.
[I think it would be interesting to think about audiophiles and purchasing decisions through the eyes of marketing. For example, I suspect research into luxury products and prototypes of "Class of Consumer" can be found in the audiophile world similar to analysis in this marketing research paper.]
Luxury non-utilitarian functions are generally motivated by “hedonic” factors. It could be as simple as esthetic preference (ooohhh… I like the size, color and braiding of that cable… It goes so well with the speakers and room decor…). But also considerably more complex individual motivations like the collector who feels happy or “complete” owning or listening to every luxury cable made, or the person who needs or wants to ensure they have “the best” of everything so is willing to “experiment” with yet another cable that claims to be better despite potentially astronomical cost. Perhaps there are social motivations at play; expensive cables satisfying the pre-requisite of the “badge of honour” that one belongs to an elite club of audiophiles, or as a status symbol of dominance / superiority among the cohort… Certainly as businesses, cable companies have financial motivations to disseminate interest in their products even if the claims are of questionable veracity. (This is of course why regulation is important in advertising.)
There are those who would view my perspective (which I think mirrors the thoughts of most objectivist audiophiles) as being overly critical, cynical, utilitarian or perhaps even born of “envy” for those who spend extravagant amounts on the audio system. While one can never exclude such possibilities unless a person has absolute psychological insight (who does?), I must admit that I have never thought of cables as particularly stimulating eye-candy (compared to an impressive pair of speakers!). I also don’t particularly care what cables are used in audio showrooms even though curious enough to attend some cable demos and run these tests. All I can say is that the other day, a friend showed off his new Lamborghini which certainly twinged infinitely more envy than I have ever experienced over anyone’s set of audio cables :-).
I. Science and Falsifiability
I’ve noticed over the years on audio forums that certain individuals will “pop” up to spew something about Karl Popper (1902-1994) as if his philosophical writings on science somehow contradicts the importance of objective exploration of audiophile claims. Usually, these comments are brief if not downright nebulous.
Popper’s claim to fame has been the concept of “falsifiability” as it applies to scientific inquiry.
. In Popper’s own words: “statements or systems of statements, in order to be ranked as scientific, must be capable of conflicting with possible, or conceivable observations”.
Now take the example of speaker cables last week. Consider the hypothesis that “speaker cables of typical electrical characteristics will create the same sonic output in typical high-fidelity systems”. Since sonic output is well understood as sound waves perceivable by us humans and there are typical electrical properties in audio systems (eg. low capacitance / inductance / impedance for cables, usual 4-8ohm speaker impedance…), one can imagine all kinds of experiments to try to falsify this statement. In my tests last week, I compared the Canare with the Kimber; of different electrical characteristics but of reasonable values to see if they produced different output from my speakers. Furthermore, I put together a terrible 12G zip cord cable of poor quality to see if I can detect sonic differences as well which would render the above statement false. I did not falsify the hypothesis in my experiment but it remains falsifiable.
We could be even more specific and hypothesize: “A Kimber 8TC is different from a zip cord cable because it produces different frequency response in a high-fidelity system”. This hypothesis was falsified with my results. Although it’s possible that in other set-ups the Kimber would perform better than a 12G zip cord, I have yet to see evidence to argue that my findings are atypical. By extension, we could do many experiments of a similar nature to test claims in the audiophile cable world – “silver cables change frequency response compared to copper thus sound brighter” would be a good one and we can produce experiments to test this belief. The bottom line is that the belief that reasonably constructed cables “sound the same” is a falsifiable claim with many potential experiments to try, therefore well within the systematic study we call science.
II. Pseudoscience in Audio (with an example)
In contrast, let’s for a moment think about pseudoscience in audio. There are many devices out there that are claimed to sonically enhance the sound system, have fancy theories, cute websites, plastered with testimonies, but provide absolutely no objective evidence that they “work” as far as I can tell. Let’s take a look at this fascinating forum post off Stereophile as a contemporary example. The basic hypothesis is that “information fields interfere with the brain”. Now this first claim / hypothesis could be falsifiable and therefore empirically testable to an extent.
Although I’m specifically referencing this post as an obvious example of pseudoscientific bovine excrement, obviously we see these kinds of disturbing claims all over the place in the world of pure subjective audiophilia. They come in various forms and severity. From naïve apologetics on the limitations of pure subjective assessment to the mind-numbing and horrifying. I think it behooves the audiophile to remain educated, and as usual in consumer matters – caveat emptor.
Comments:
I think audiophoolery exploits the irrational fear in some people that they might miss out on some improvement. Once a claim catches on by people deluding themselves the circle jerk starts and who wouldn’t want to be part of that.
Reality and “truth” is completely irrelevant.
And hence the comment on “hedonic motivations”. This permeates through all types of luxury items of course, not just audio… Women buy very expensive LV bags for example but they know that money doesn’t necessarily correlate with larger size or more durability (the utilitarian functions). Owning the “elite” goods feels good and they are status symbols as well.
From my perspective, there’s actually *nothing wrong* with this and I hope in my writing this doesn’t offend anyone. Splurging on luxury goods is normal. Fancy cars, fancy clothes, fancy house, expensive audio… No problem. It’s one’s money and one has the right.
My issue is about the belief that expensive cables mean “better sound”. That what is luxury actually has an impact on the basic utilitarian goal of the cable itself (efficient transmission of electrical signal). That IMO is the lie when perpetuated.
I agree. It’s like saying some luxury hand bag can store junk better, even though it may actually be smaller, have a less practical shape, or may be completely identical except for a different label …
I also don’t care if someone spends $1k on a piece of cable that costs a few bucks to make, I just feel sorry for those who save their hard-earned money to buy such a product not to miss out on the promised audible improvements that are a lie.
Hi Archimago,
“It’s a wrap”. Perhaps you’ve just nailed it, the myths about cables, I mean.
But maybe they’re not myths after all; maybe the affects you describe as pseudoscience in your article are real, and tangible in some way.
Consider the analogy of the expensive handbag. Let’s agree that the utility offered by that bag is no more than that offered by a cheap bag
the carrying of that bag makes them feel good. What is the effect? They carry their stuff around just the same, but they feel better, they walk more confidently and assuredly, and therefore they look better. (The transformed girl walking confidently in her new found beauty whilst all eyes are askew is one of the oldest clichés in Hollywood). That is a direct, tangible effect of a luxury item. Therefore, for some people (only some I suggest) there is a utility in that item, that others don’t get, or can’t carry off.
Let’s now think about sound and hearing. Sound doesn’t change; I mean at any given time, in any one place, it’s the same for you and me. But what we hear does change. Depending on time and place and context, we listen more intently, or ‘tune out’ to get only the signals we think we need. Is it too much to extrapolate the ‘extra utility of luxury items’ to that of cables and tweaks? The head turning girl walking down the street carrying a very fine hand bag, then becomes analogous to the joy that someone gets having just laid out $1000 on an Ethernet cable. Sure, for the audiophile, it’s a personal joy, but can’t it be just as real? Couldn’t it be that for that person, in their anticipation, their hearing gets enhanced, much like the gait of the beautiful girl?
That’s my Popper contribution.
For what it’s worth, I’m convinced that much of what is written about audiophile gear needs to be offloaded to the aforementioned farmer so he can spread it across his fields, but I’m open to some ‘utility’ in more expensive cables beyond their measured electrical characteristics.
A-BX testing could help address much of the confusion, and the failure to try and understand the objective, verifiable reasons for sonic improvement is shameful exploitation by the industry and a curse that will condemn many of those those who enjoy hi-fi to carry the label ‘audiophool’. Unfortunately, too many times, it’s a tag that is justified.
On the bright side, much of the expensive stuff that offers no extra utility gets recycled. The classifieds offers one such outlet
Signaling Status with Luxury Goods: The Role of Brand Prominence
https://journals.sagepub.com/doi/10.1509/jmkg.74.4.015
This research introduces “brand prominence,” a construct reflecting the conspicuousness of a brand’s mark or logo on a product. The authors propose a taxonomy that assigns consumers to one of four groups according to their wealth and need for status, and they demonstrate how each group’s preference for conspicuously or inconspicuously branded luxury goods corresponds predictably with their desire to associate or dissociate with members of their own and other groups. Wealthy consumers low in need for status want to associate with their own kind and pay a premium for quiet goods only they can recognize. Wealthy consumers high in need for status use loud luxury goods to signal to the less affluent that they are not one of them. Those who are high in need for status but cannot afford true luxury use loud counterfeits to emulate those they recognize to be wealthy. Field experiments along with analysis of market data (including counterfeits) support the proposed model of status signaling using brand prominence.
Tomi Engdahl says:
Analog circuit performance is often affected adversely by high frequency signals from nearby
electrical activity. And, equipment containing your analog circuitry may also adversely affect
systems external to it.
http://www.analog.com/media/en/training-seminars/tutorials/MT-095.pdf
EMC is the ability of a device, unit of equipment, or system to function satisfactorily in its
electromagnetic environment without introducing intolerable electromagnetic disturbances to
anything in that environment.
The term EMC therefore has two aspects:
1. It describes the ability of electrical and electronic systems to operate without
interfering with other systems.
2. It also describes the ability of such systems to operate as intended within a specified
electromagnetic environment
The externally produced electrical activity may generate noise, and is referred to either as
electromagnetic interference (EMI), or radio frequency interference (RFI). In this section, we
will refer to EMI in terms of both electromagnetic and radio frequency interference. One of the
more challenging tasks of the analog designer is the control of equipment against undesired
operation due to EMI. It is important to note that in this context, EMI and or RFI is almost
always detrimental. Once given entrance into your equipment, it can and will degrade its
operation, quite often considerably.
This section is oriented heavily towards minimizing undesirable analog circuit operation due to
the receipt of EMI/RFI. Misbehavior of this sort is also known as EMI or RFI susceptibility,
indicating a tendency towards anomalous equipment behavior when exposed to EMI/RFI.
EMI/RFI MECHANISMS
To understand and properly control EMI and RFI, it is helpful to first segregate it into
manageable portions. Thus it is useful to remember that when EMI/RFI problems do occur, they
can be fundamentally broken down into a Source, a Path, and a Receiver. As a systems designer,
you have under your direct control the receiver part of this landscape, and perhaps some portion
of the path. But seldom will the designer have control over the actual source.
NOISE COUPLING MECHANISMS
EMI energy may enter wherever there is an impedance mismatch or discontinuity in a system. In
general this occurs at the interface where cables carrying sensitive analog signals are connected
to PC boards, and through power supply leads. Improperly connected cables or poor supply
filtering schemes are often perfect conduits for interference.
Conducted noise may also be encountered when two or more currents share a common path
(impedance). This common path is often a high impedance “ground” connection. If two circuits
share this path, noise currents from one will produce noise voltages in the other.
MT-095
EMI COUPLING PATHS
The EMI coupling paths are actually very few in terms of basic number. Three very general
paths are by:
1. Interference due to conduction (common-impedance)
2. Interference due to capacitive or inductive coupling (near-field interference)
3. Electromagnetic radiation (far-field interference)
NOISE COUPLING MECHANISMS
EMI energy may enter wherever there is an impedance mismatch or discontinuity in a system. In
general this occurs at the interface where cables carrying sensitive analog signals are connected
to PC boards, and through power supply leads. Improperly connected cables or poor supply
filtering schemes are often perfect conduits for interference.
Conducted noise may also be encountered when two or more currents share a common path
(impedance). This common path is often a high impedance “ground” connection. If two circuits
share this path, noise currents from one will produce noise voltages in the other. Steps may be
taken to identify potential sources of this interference (see References 1 and 2, plus tutorial MT-
031).
Figure 2 shows some of the general ways noise can enter a circuit from external sources.
z
z
Impedance mismatches and discontinuities
Common-mode impedance mismatches → Differential Signals
Capacitively Coupled (Electric Field Interference)
dV/dt → Mutual Capacitance → Noise Current
(Example: 1V/ns produces 1mA/pF)
Inductively Coupled (Magnetic Field)
di/dt → Mutual Inductance → Noise Voltage
(Example: 1mA/ns produces 1mV/nH)
Figure 2: How EMI finds Paths into Equipment
There is a capacitance between any two conductors separated by a dielectric (air and vacuum are
dielectrics, as well as all solid or liquid insulators). If there is a change of voltage on one
conductor there will be change of charge on the other, and a displacement current will flow in
the dielectric. Where either the capacitance or the dV/dT is high, noise is easily coupled. For
example, a 1-V/ns rate-of-change gives rise to displacement currents of 1 mA/pF.
If changing magnetic flux from current flowing in one circuit couples into another circuit, it will
induce an emf in the second circuit. Such mutual inductance can be a troublesome source of
noise coupling from circuits with high values of dI/dT. As an example, a mutual inductance of 1
nH and a changing current of 1 A/ns will induce an emf of 1 V.
NOISE INDUCED BY NEAR-FIELD INTERFERENCE
Crosstalk is the second most common form of interference. In the vicinity of the noise source,
i.e., near-field, interference is not transmitted as an electromagnetic wave, and the term crosstalk
may apply to either inductively or capacitively coupled signals
REDUCING CAPACITANCE-COUPLED NOISE
Capacitively-coupled noise may be reduced by reducing the coupling capacity (by increasing
conductor separation), but is most easily cured by shielding. A conductive and grounded shield
(known as a Faraday shield) between the signal source and the affected node will eliminate this
noise, by routing the displacement current directly to ground.
With the use of such shields, it is important to note that it is always essential that a Faraday
shield be grounded. A floating or open-circuit shield almost invariably increases capacitively-
coupled noise.
REDUCING MAGNETICALLY-COUPLED NOISE
Magnetic field coupling can be reduced by
reducing the circuit loop area, the magnetic field intensity, or the angle of incidence. Reducing
circuit loop area requires arranging the circuit conductors closer together. Twisting the
conductors together reduces the loop net area. This has the effect of canceling magnetic field
pickup, because the sum of positive and negative incremental loop areas is ideally equal to zero.
Reducing the magnetic field directly may be difficult. However, since magnetic field intensity is
inversely proportional to the cube of the distance from the source, physically moving the affected
circuit away from the magnetic field has a very great effect in reducing the induced noise
voltage. Finally, if the circuit is placed perpendicular to the magnetic field, pickup is minimized.
If the circuit’s conductors are in parallel to the magnetic field the induced noise is maximized
because the angle of incidence is zero.
There are also techniques that can be used to reduce the amount of magnetic-field interference, at
its source. In the previous paragraph, the conductors of the receiver circuit were twisted together,
to cancel the induced magnetic field along the wires. The same principle can be used on the
source wiring. If the source of the magnetic field is large currents flowing through nearby
conductors, these wires can be twisted together to reduce the net magnetic field
Shields and cans are not nearly as effective against magnetic fields as against electric fields, but
can be useful on occasion. At low frequencies magnetic shields using high-permeability material
such as Mu-metal can provide modest attenuation of magnetic fields. At high frequencies simple
conductive shields are quite effective provided that the thickness of the shield is greater than the
skin depth of the conductor used (at the frequency involved). Note—copper skin depth is 6.6/√f
cm, with f in Hz
PASSIVE COMPONENTS: YOUR ARSENAL AGAINST EMI
Passive components, such as resistors, capacitors, and inductors, are powerful tools for reducing
externally induced interference when used properly.
Simple RC networks make efficient and inexpensive one-pole, low-pass filters. Incoming noise
is converted to heat and dissipated in the resistor. But note that a fixed resistor does produce
thermal noise of its own
In applications where signal and return conductors aren’t well-coupled magnetically, a common-
mode (CM) choke can be used to increase their mutual inductance.
A CM choke can be
simply constructed by winding several turns of the differential signal conductors together
through a high-permeability (> 2000) ferrite bead. The magnetic properties of the ferrite allow
differential-mode currents to pass unimpeded while suppressing CM currents
Capacitors can also be used before and after the choke, to provide additional CM and
differential-mode filtering, respectively. Such a CM choke is cheap and produces very low
thermal noise and bias current-induced offsets, due to the wire’s low dc resistance. However,
there is a field around the core. A metallic shield surrounding the core may be necessary to
prevent coupling with other circuits. Also, note that high-current levels should be avoided in the
core as they may saturate the ferrite.
Applying the concepts of shielding effectively requires an understanding of the source of the
interference, the environment surrounding the source, and the distance between the source and
point of observation (the receiver). If the circuit is operating close to the source (in the near, or
induction-field), then the field characteristics are determined by the source. If the circuit is
remotely located (in the far, or radiation-field), then the field characteristics are determined by
the transmission medium.
A circuit operates in a near-field if its distance from the source of the interference is less than the
wavelength (λ) of the interference divided by 2π, or λ/2π. If the distance between the circuit and
the source of the interference is larger than this quantity, then the circuit operates in the far field
Regardless of the type of interference, there is a characteristic impedance associated with it. The
characteristic, or wave impedance of a field is determined by the ratio of its electric (or E-) field
to its magnetic (or H-) field. In the far field, the ratio of the electric field to the magnetic field is
the characteristic (wave impedance) of free space, given by Zo = 377 Ω. In the near field, the
wave-impedance is determined by the nature of the interference and its distance from the source.
If the interference source is high-current and low-voltage (for example, a loop antenna or a
power-line transformer), the field is predominately magnetic and exhibits a wave impedance
which is less than 377 Ω. If the source is low-current and high-voltage (for example, a rod
antenna or a high-speed digital switching circuit), then the field is predominately electric and
exhibits a wave impedance which is greater than 377 Ω.
Conductive enclosures can be used to shield sensitive circuits from the effects of these external
fields. These materials present an impedance mismatch to the incident interference, because the
impedance of the shield is lower than the wave impedance of the incident field. The effectiveness
of the conductive shield depends on two things: First is the loss due to the reflection of the
incident wave off the shielding material. Second is the loss due to the absorption of the
transmitted wave within the shielding material. The amount of reflection loss depends upon the
type of interference and its wave impedance. The amount of absorption loss, however, is
independent of the type of interference. It is the same for near- and far-field radiation, as well as
for electric or magnetic fields.
Reflection loss at the interface between two media depends on the difference in the characteristic
impedances of the two media.
For magnetic fields, the loss depends also on the shielding material and the frequency of the
interference.
Absorption is the second loss mechanism in shielding materials.
Since the intensity of a transmitted field decreases exponentially
relative to the thickness of the shielding material, the absorption loss in a shield one skin-depth
(δ) thick is 9 dB. Since absorption loss is proportional to thickness and inversely proportional to
skin depth, increasing the thickness of the shielding material improves shielding effectiveness at
high frequencies.
Reflection loss for plane waves in the far field decreases with increasing frequency because the
shield impedance, Zs , increases with frequency. Absorption loss, on the other hand, increases
with frequency because skin depth decreases. For electric fields and plane waves, the primary
shielding mechanism is reflection loss, and at high frequencies, the mechanism is absorption
loss.
Thus for high-frequency interference signals, lightweight, easily worked high conductivity
materials such as copper or aluminum can provide adequate shielding. At low frequencies
however, both reflection and absorption loss to magnetic fields is low. It is thus very difficult to
shield circuits from low-frequency magnetic fields. In these applications, high-permeability
materials that exhibit low-reluctance provide the best protection. These low-reluctance materials
provide a magnetic shunt path that diverts the magnetic field away from the protected circuit.
Examples of high-permeability materials are steel and mu-metal.
GENERAL POINTS ON CABLES AND SHIELDS
Although covered in detail elsewhere, it is worth noting that the improper use of cables and their
shields can be a significant contributor to both radiated and conducted interference.
Depending on the type of interference (pickup/radiated, low/high frequency), proper cable
shielding is implemented differently and is very dependent on the length of the cable. The first
step is to determine whether the length of the cable is electrically short or electrically long at the
frequency of concern. A cable is considered electrically short if the length of the cable is less
than 1/20 wavelength of the highest frequency of the interference. Otherwise it is considered to
be electrically long.
For example, at 50/60 Hz, an electrically short cable is any cable length less than
150 miles, where the primary coupling mechanism for these low frequency electric fields is
capacitive. As such, for any cable length less than 150 miles, the amplitude of the interference
will be the same over the entire length of the cable
In applications where the length of the cable is electrically long, or protection against high-
frequency interference is required, then the preferred method is to connect the cable shield to
low-impedance points, at both ends. As will be seen shortly, this can be a direct connection at the
driving end, and a capacitive connection at the receiver. If left ungrounded, unterminated
transmission lines effects can cause reflections and standing waves along the cable. At
frequencies of 10 MHz and above, circumferential (360°) shield bonds and metal connectors are
required to main low-impedance connections to ground.
In summary, for protection against low-frequency (1 MHz), the
preferred method is grounding the shield at both ends, using 360° circumferential bonds between
the shield and the connector, and maintaining metal-to-metal continuity between the connectors
and the enclosure.
However in practice, there is a caveat involved with directly grounding the shield at both ends.
When this is done, it creates a low frequency ground loop
As noted above, cable shields are subject to both low and high frequency interference.
practice requires that the shield be grounded at both ends if cable is electrically long
However, safety considerations may require that the remote end of the shield also be grounded.
Coaxial cables are different from shielded twisted pair cables in that the signal return current
path is through the shield. For this reason, the ideal situation is to ground the shield at the driving end and allow the shield to float at the differential receiver
the receiver may be a single-ended type, such as typical of a standard single op amp
so there is no choice but to ground the coaxial cable shield at both ends for this case.
Tomi Engdahl says:
https://www.facebook.com/groups/DIYAudio/permalink/5753692291363236/
I have a similar setup, with a 4.5m cable between my phonostage and preamp. As I have upgraded over the years I have tried many solutions, finally using balanced outputs on the phono stage into a balanced input on the preamp.
However I tried various unbalanced cables before.
Basically 10m of cables is 10x 1m of capacitance. So you really need to find low cap cable and that is SINGLE core shielded. Having more than one conductor increases capacitance though lowers inductance. And you need two or three shields – foil and braid or semiconductor carbon and braid. A good example is Sommer Spirit LLX which I have used for interconnects. They sound good and have a carbon semiconductor and copper braid shield. They are not expensive. £450 a meter of similar.
The normal studio microphone type cable has no foil shield as is thus not 100% shielded, and has capacitances of double the instrument cable I’ve suggested here.
Another suggestion is to buy a 10m component video cable from a good manufacturer, just remove the third cable. These are REALLY well shielded or you’d see “snow” on your screen. They work perfectly well for audio cable and are usually very well made. If you can find silver plated component video vocable even better! Try eBay, these are usually quite cheap as nobody uses component video cable anymore!
https://www.shootoutguitarcables.com/guitar-cables-explained/capacitance-chart.html
Wayne Grundy
“A good example is Sommer Spirit LLX which I have used for interconnects. They sound good and have a carbon semiconductor and copper braid shield. They are not expensive. £450 a meter of similar.”
I
Where did you get that cable price
Here Sommer Cable The Spirit LLX is 2.66 Euros per meter
https://www.thomann.de/fi/sommer_cable_the_spirit_llx.htm
Tomi Engdahl says:
“length of 10m. These cables will connect my phono preamp to my preamp.”
My questions :
Do I use :
“2 conductors cable ? ( VDH Flexicon for instance)”
Shielded two conductor cable works for interconnections OK.
“2×1 conductor wire? ( just a insulated wire)”
Just insulated wire is a bad choice for this kind of signal interconnection. This type of cable works ok speaker connection only, it is wrong choice for pretty much all other audio interconnections. Especially with unbalanced hifi connections cable without shield picks up noise far too easily.
“Shielded cables?”
Shielded cables are the right choice. For unbalanced interconnections coaxial cable construction works well. Also shielded twisted pair cable is OK.
Tomi Engdahl says:
Not directly related to the cable, but in your case I’d check the output resistance of the phono stage, to make sure it can drive such long cables without sigbificant high frequency loss…
Tomi Engdahl says:
From https://www.facebook.com/groups/DIYAudio/permalink/5776596315739500/
Hello everybody. Are there any benefits to using OFC for speaker cables? Because if it is all marketing smoke and mirrors, I will just use some pure copper zip cord.
Thanks
Every copper cable is OFC ( Oxigen Free Copper ), cause every copper cable ( not mixed with other stuff ), has 99,9, what ever, copper…
Google… production process of copper.
And you will see two things.
1. Even the cable in the wall, for your 110 / 230 V power is OFC.
2. It is a genius marketing strategy of the hifi vodoo guys, to make marketing with a normal factory process. To make this or that cable, very special
End
in home hi-fi lengths, typical gauge speaker cable (e.g. zip cord) has zero audible interaction with those other elements. That’s also true of the amplifier, tube amps excepted. In other words, what you’re hearing is the amp (frequency response, distortion characteristics) and, separately, the speaker (crossover + drivers + geometry + cabinet), and separately again, the room. The cable doesn’t come into it. It’s completely irrelevant. Supposed audible differences in cable are imagined, and no blind ABX testing has ever shown otherwise
Steady state frequency domain analysis does not include the transient portion of a time domain signal. Further, not all distortion mechanisms correlate well with THD measurements.
S domain = Sigma (transient
component)
+ j Omega (steady
state frequency
component).
The Fourier transform only contains the j omega steady state term, not the transient Sigma term.
Also, hysteresis and other non-linear effects effects are not necessarily well accounted for in the frequency domain. Many of the subjective differences in sound quality of equipment are due to hysteresis and other non-linear distortions affecting the transient, time domain component of an audio waveform.
The debate between the merits of subjective listening evaluation versus objective measurements has been going on for at least 75 years, when DTN Williamson first discussed subjective sound quality issues in Wireless World, April 1947 with the Williamson amplifier.
Since the late 1960s, home audio has been divided between the mid-fi market segment and the high end market segment.
Excessive faith in steady state frequency domain analysis appears to be one issues holding back reconcilliation in this area.
You are under absolutely no obligation to accept or believe any of what I say.
If you are absolutely convinced that steady state frequency domain and impulse response analysis/measurements will tell you everything about an audio system’s performance, then there probably isn’t any value in discussing this further.
Tomi Engdahl says:
I wonder who didn’t know how energy flows in the wires?
almost everyone in the world, 98% of audiophiles, everyone that sells cables in shops “they are directional sir” etc. consider yourself one of the very few educated people!
I would believe people would think about how energy is transmitted in an alternate wave. Cannot be the flow of electrons, they keep going back and forth…
But cables can be “directional” not for the signal but for the shielding.