Dec 15, 2010 01:01 am Well, thing is, if you are recording the output signal from the laptop's speaker or headphone jack, it's going to catch everything that you would normally hear on the speakers or the headphones, so, mic input and everything else. You're just recording a signal, and there's no way to take an existing signal and segregate it into its parts. You have to segregate at the source, which means, recording from the headphones without having anything else playing in the background.
However, and there may be an easier way that someone else can recommend, but what you can do is isolate the input signal while recording if you're using software. One way you can do it is run some recording software (like audacity) set up a track to record from the mic-in, and that track will capture the input from the mic alone, but not anything you have playing in the background. Just the signal coming from the mic-in.
Then, you'll need to play back the wave file you create, and you should be able to capture the isolated signal out from the laptop that way.
If, however you are recording this in real-time as you're doing something, say playing a game, or singing with a background track, etc. And you're recording to an extrenal device directly off the laptop's speaker/headphone jack, then I'm not sure you'll be able to isolate the sound unless you just use the headphones and don't have anything at all playing in the background.
Maybe there's a way to pan mic input hard left and all playback hard right so that in the stereo signal, the left channel will be the mic input and right channel will be the other junk? Not sure on that. And, you'd still need to edit the wave to delete all the stuff in the right channel, and pan the left channel back to center, which would probably require some wave editing software of some sort.
Maybe one of the studio gurus can chime in. I just don't think you can split a signal coming off a headphone/speaker jack.