it appears to be an 8-bit music file. I have had this issue posted before - this is the response i got from the BASS developer:
"The problem is that the MP3 data has a plain PCM WAVE header (WAVE_FORMAT_PCM) in front of it, so BASS treats it as a PCM WAVE file. Do you know how the file was created? My guess is that an ACM codec was used but an incorrect WAVE header was written (it should be WAVE_FORMAT_MPEGLAYER3)."