The worst thing for an MPEG audio encoder to have to encode is white noise because it contains a wide range of frequencies. This is noticeable at low bit rates with applause.

You're right, of course. I think we're both saying the same thing in different ways. In most music, rarely do you find high frequency content that isn't white noise. Perhaps certain synthesizer filter sweeps could produce sounds that are both high frequency and made up of regular patterns. Such things would probably data-compress quite well. You also might find regular data patterns in guitar feedback or portions of the sound from ultra-high tuned percussion instruments like triangles. But for the most part, if there's high frequency content in a piece of music, it's from white-noise sources like cymbals, vocal sibilance, and applause (as you said).

Tony Fabris
Empeg #144