Prevent recording output sound

[Snigel]

Hi,

I'm looking for a way of preventing Ubuntu (11.10) from recording output sound. I'm using earphones to listen to audio and simultaneously recording from a separate microphone, but regardless of what I do, I can hear the audio I listen to on the recording. Since I'm using earphones, there's no way the microphone can pick up the sound and record it that way, it has to be internal somehow.

In case this isn't clear enough, this is what I want to do:

1) Listen to an audio source using earphones (such as a speech)
2) Simultaneously record using the microphone (mimicking the speech)
3) Without hearing the source audio on the recording

And this is what happens:

1) I can hear the original speech in the background of my own recording
2) If I just play the speech, it still registers as input on the microphone

I want to prevent this from happening!

[Thee]

Hm, that really shouldn't happen. What software are you using to record? Does this happen in every app that you record in or only in one? From which app is the sound coming from?