mlsoundtap

I'm not a computer expert, but when I record a 20 minute program with soundtap I get a 200 MB file. When I look at music files from my ripped cds, I see that one four minute song is about 3.5 MB, which would be 14 MB if the song was 20 minutes long. So why are the soundtap recordings so big? Is there a way to make them smaller and not compromise quality? Please only respond with relatively simple explanations. Thanks!