Although this does not help you directly unfortunately, I have seen this concept has come up often - but the way that Windows handles audio output does not currently allow this by default (you can configure which Playback and Recording Devices to utilize, but it is difficult for a recording program to record from 'just one running application and not the others', in Windows.
If you really don't want to record a game you are playing without the extra Music/TV/etc running, you can simply run all of your other audio on another system (a laptop, for instance) or another device (a stereo, mp3 player, etc) - but if you only have one machine/source for all of your audio, there is a workaround for doing it all on one system I can suggest (since I have used this method myself):
/signing for Raptr to add this functionality in the future!
Unfortunately, the capability/configurability for Windows (and most games), to record from 'just that one audio stream source', is rare to do by default... There may be Software-Only ways to get the above done too, but I have not used those or researched that myself yet, so I cannot say at this time, sorry. Good luck with it, though.
thanks for the reply gametipsandmore
I see what you're saying and understand your workaround (quite a workaround at that!)
Luckily I have a tablet and I noticed my speakers have a separate audio-in on the on-desk control pod thing, so I now play music from my tablet directly to the speakers that way. Not completely ideal, and I have to make sure I don't play any other audio in the background on my PC, but it will suffice for now.
You are most welcome
Way to go - now you won't have to worry about your videos anymore /thumbsup