Newsgroups: rec.audio.tech Subject: Re: Audio/Video Splitting References: <[email protected]> [email protected] (DanG2015) writes: > I'm sure this has been discussed ad nauseum, but I couldn't find anything > relevent with a quick google search, so if you could put up with one more > splitting question ;-) > > On a video device with RCA S-Video and R/L audio outputs, I need to > feed the signal to a few devices. In this particular case, I have an HDTV > receiver with one S-Video output, one R/L audio, and a set of component > video outputs. > > The component video goes to the TV (good). The audio goes to the > TV (good). > > But I'd like the audio and S-video to go to a modulator for whole-house > distribution [yes, I do know that it would be regular old NTSC, not HD], > to a recorder, and the audio one more time to the home theatre amp > [see note below]. > > So that's a couple splits for the S-video and even more for the audio. > I was looking at a neat splitter cable from ChannelPlus > (http://www.multiplextechnology.com/channelplus/products/music/2743.html) > but I don't know how many times you can split S-video and audio without > hurting it. I'm not after 100% performance here, but I don't want 75% either. > > I *assume* that the source S-video and audio drivers are decent and that > all the receiver inputs are high impedance, so as far as sucking signal levels > down, I'm guessing I'm OK, but I'm not sure about termination, ringing, etc. > Am I kidding myself? For audio applications Y-splitting the signal to 2-4 devices is OK. The outputs is quite low impedance and the inputs are high impedance. For baseband video signal interfaces (this includes composite video, S-video, component video, RGB) things are different. All the outputs and inputs are designed to have 75 ohm impedance. If you connect one output to more then one input, you create an impedance mismatch that cause sigla level dropping and possibly signal reflection problems (visible on long cables). It depends on the devices used, but sometimes with short cables splitting one video output to two input works quite OK, usually makes the picture slightly darker. Sometimes thing get more messed up (some devices might not sync to weak signal at all etc.O) > If I cannot Y-cable split these, any suggestions? For video signals you need a video splitter / distribution amplifier. > If I get a distribution S-video/audio splitter, won't these add noise into > the system as much as splitting would hurt? A well designed S-video splitter does not add any noise to the picture you would notice. Using a proper amplifier for video is always better than direct splitting and hurts signal less. > I'd surely appreciate anyone > who knows their stuff to comment briefly on this. > > I tried connecting the home theatre amplifier to the MONITOR OUT on the > TV (fairly recent & decent HDTV) but I have to crank the TV volume and > the amp volume to get good levels out of it. So I'm thinking that I should > feel the amp with direct feeds from each video/audio source... offhand, > (generally), is feeding from the TV MONITOR OUT audio line an "OK" thing, > or is it generally thought be a crappy thing to do? > > Thanks in advance, > > Dan -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
