I'm trying to clean up a recording made from the radio about ten years ago. I believe it was dubbed to cassette at one point. The energy for the whole file seems to go "down" more than it goes "up". It's almost like the DC Offset Bias is bad, but that doesn't appear to be the case. The result is audio that sounds overdriven or clipped even though it's nowhere near 0dB.

Does anyone know what the description of this problem is? I'm using Cool Edit Pro (1.3) and I'm sure I can fix it in there, but searches in the help file aren't showing anything because I dion't know what it's called...