Prevent audio recording applications from picking up non-microphone audio output

Question

When talking to people over Mumble/Teamspeak/Ventrilo, I have a few who are broadcasting all of their audio output (e.g. music playing in the background, game sounds, etc.) whenever they are sending -- in addition to the microphone signal.

I don't have this problem myself, so it's hard for me to troubleshoot remotely, but I'm interested in collecting solutions for this problem for Windows XP, Vista and 7, so that I can link them to this question.

Links to other related SU questions are highly welcome as well, but I couldn't find any. Most people seem to try to either get microphone to feed back into the audio output or turn exactly that off, which is different from this problem. I'm talking about the opposite problem, the output being fed into the input.

I'll assume that it has been ruled out at that point that it's just the microphone picking up the actual audio waves from the speakers. The person is wearing headphones and probably using push-to-talk.

Answer 1

For the most part this is actually caused by the fact the mic is picking up these sounds from the speakers. So there are generally two ways to go about fixing it, if that is indeed the issue.

First off goto push to talk mode which TS/Vent have (not sure about Mumble). That would prevent the 'constant' stream of sound you say you hear.

The second thing is for the people to use headphones. This isolates the sound so the mic can't pick it up.

Answer 2

There are separate volume controls for recording and playing where you can mute different audio types.

On WindowsXP you can can run "sndvol32.exe /R" to get the recording volume control. And then mute everything except the microphone.
There is also a way to get to that dialog from the playing volume control that you get when double-clicking the loudspeaker tray icon. But I forgot the exact click path.

No idea how to do it on newer versions of windows since they completely changed how audio works in vista.