I have been capturing audio from a site called "Name My Tune", where people sing or whistle a tune into their computer in hopes someone will identify it. There's an odd kind of distortion that shows up in a lot of the samples posted - a clicking noise that sounds like clipping distortion due to overmodulation, but if you look at the waveform on an editor like Audacity, you don't see the characteristic "broken" peaks. And it seems to happen whether the source is loud or soft. Here's what one sample looks like. Top: an 8 sec. clip. Bottom: close-up from the same sample Notice there seems to be some ultra-low frequency mixed into the signal. I can eliminate that for the most part by using a low-cut filter, but the "clipping" noise remains, which tells me it's not just a matter of my dinky computer speakers not being able to handle the subsonic signal. Here's the clip I'm talking about - hear the buzzing noise? So can anyone suggest how to fix this? Thanks, Peter.