I don't know if this will help, but here are my thoughts. Is it possible that you are used to working with mp3 files but you have
SoundTap's output format set to wav? (click on Options tab : Output format.) It can be set to mp3, with more advanced options also.
I only work with wav files so I can't help with those.
Example of my thinking: a 3.5 minute song recorded as a wav file (bit rate : 4411 kbps) will be @ 34 MB.
Is this of any help? Vapors