soundcard issue

[mikehende]

I would like to run 2 separate music programs and would like to run each program to a different set of speakers, can I use 2 soundcards to do this or is there any way to do this using just the one soundcard that comes with the pc?

[GavinO]

As far as I know, Windows only allows you to select one sound device at a time for output. If you have 4-channel output, and your music programs support front/rear balance, you could set something up with that (pan one program full front, one full rear, and then hook different speakers to the front and rear outputs)

[mikehende]

Am I correct that this simply cannot be done with the convention soundcard that comes with every pc, that is the one that has just 1 lineout? So this means that I will have to get either another sc or replace the existing sc with one that has more outputs?

[GavinO]

Correct, a sound card with only a single stereo output cannot drive two separate stereo setups. I suppose, though, that if you can deal with mono sound, you could pan one source all left and one all right, and use a stereo splitter on the output to drive two setups. With either the front/rear split or the left/right split, though, I think you might wind up with some degree of crossover between the signals, as sound hardware is generally expecting all of the channels to have somewhat similar signals on them.

[mikehende]

I have been told this exact thing on one of my music forums Gavin but what I simply can't understand is this, "how" will you get to separate even a mono sound into 2 parts when it's coming through just 1 output channel?

[GavinO]

If you have a single 1/8" stereo out (like on most onboard sound cards) you simply need a channel splitter. You can either pick up a 1/8" stereo male jack and a pair of 1/8" mono female jacks from Radio Shack and solder something together, or look into something like this: http://www.maplin.co.uk/Module.aspx?ModuleNo=43086&TabID=1&C=SEO&U=SEOsearchPages&doy=search

[mikehende]

That is what I have right now [appreciate the link], I still have a hard time understanding how even 2 separte [left and right] mono signals can come through a single 1/8 output but I'll take your word for it, appreciate the help Gavin, take it easy.

[GavinO]

You 1/8" stereo plug looks something like this:

_______________
              |_______________   _
              |     | |   | | \_/ \
              |     | |   | |  _   |
              |_____|_|___|_|_/ \_/
_______________|  |   |  |  |   |
                 |   |  |  |   |__ Metal (ground)
                 |   |  |  |______ Plastic
                 |   |  |_________ Metal (signal)
                 |   |____________ Plastic
                 |________________ Metal (signal)

Note how there are 3 parts to the tip, separated by plastic rings. The part at the very end is a common ground, and the other two are signal lines. A mono plug looks similar, but is lacking the divider between the left two segments (allowing for only one signal on the wire). Because there are entire conductors (wires) dedicated to each channel, nothing complicated needs to be done to separate left and right signals (you just connect them internally to the left and right speakers).

 

For a surround sound setup, two stereo connectors are typically used, one for the front speakers and one for the rear. This allows us to maintain 1 conductor per channel. For digital connections (ie, Dolby Digital or AC97), you actually use a mono plug. The digital transmission specification samples all of the signals (some configurations use as many as 8) and combines them into a single signal. The receiving end is much more complicated (if you connect a digital output to a speaker, you will either hear nothing or a sound akin to a modem), as the signal needs to be broken into the original channels and reconstructed from the samples.