Newsgroups: rec.audio.tech
Subject: Re: In Search Of: "FREE" Audio Measurement Software
References: <[email protected]>
"Earthlink"  writes:

> Hello,
> 
> I'm new to this group.
> 
> I am in search of FREE Audio Measurement Software. Specifically,(sound
> pressure level, and spectrum analyzation). I have found several sites that
> offer this type of software... but at a price. I don't need all the options
> that these pay-for softwares offer.

Try the following software link pages:
http://www.epanorama.net/audiospeakers.html#measure
http://www.epanorama.net/pc/sound.html#software

> If nothing else, the (SPL) meter is what
> I need. This would be for use on a laptop with a microphone attached to
> measure DB levels.

For computer measurements to get SPL meter to work accurate is
more demanding task than getting some frequency response measumement right.
The acutal technology in SPL meter is easy. Calculating the relative
decibels from sound samples is easy mathematics, but
getting accurate SPL measurement you would need a known reference
to set all the relative decibels right. The reference would
be what kind of signal gets to the computer at certain
known decibel level (propably measured with other
meter or taken from some reference sound generator).
The value what gets ito the computer from the air from known
sound depends very much on the microphone specifications
(different microphones have different sensitivities and
the sensitivity can vary from microphone to microphoneunit
and how it is connected), then the soundcard affects this
measurement and the settings of soundcard. If yo have a reference
to cablibrate the system and then you can always get reliably to
the know settings in computer then you can use it as an SPL
meter.

> I cannot believe that a $2k laptop cannot be made to emulate a $50 measuring
> tool without paying a hefty price... therefore I am in search for such FREE
> software.
> 
> Any help is appreciated
> 
> TIA
> GEO�
> 
> 
> 

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/