We are using Audacity to record interviews through google voice, but unfortunately, the voices of the interviewees are consistently much fainter than the voices of the interviewers on the recording. Is there a way to permanently adjust the way the volume of the interviewee’s voice is recorded (as opposed to editing the sound afterwards)? The interviewer wears a Logitech headset with mouthpiece in order to record their voice, and inside that they wear a one-sided headphone to record the audio coming in from the other end of the conversation. The interviewee is using a landline. This is being done on a Windows 7 computer and Audacity 2.0.3. Thanks!! 
I’m on the fourth reading and I can’t connect how you’re doing this.
If there’s a landline, why do you need Google Voice?
inside that they wear a one-sided headphone to record the audio coming in from the other end of the conversation.
You can’t record sound from a headphone. That may be where I’m losing it.
Doing remote recordings is rough. Getting a good land-line recording can run into the many hundreds of dollars for a Telephone Hybrid Recorder (how radio stations do it).
You may be trying to do too many things on one computer. I ran into that when I did my none-too successful experiments with recording VOIP.
Koz