IDM Mailing Archive

Irene McC wrote:

quoted 12 lines Just a general MP3 related question: a lot of MP3's I'm listening to

> > Just a general MP3 related question: a lot of MP3's I'm listening to > are distorted, either at the top end which clips, or the bass which > just goes "bbsshhh" - and looking at the actual curve, it makes > standing squared waves. > > Presumably this is not due to the extraction, but comes from the > original source - is it because people use huge compression on their > sound files? Is there any way around it? Even if I convert my own > CD's to MP3, I cannot predict which ones will come out distorted > (and many do). Selecting the "normalize" function does not seem > to help - sometimes it even boots the gain.

What bitrate are the MP3 files? At low bitrates, the "psycho-acoustic model" that the MP3 compression algorithm uses has a tendency to throw away data at the very top and the very bottom of the audible spectrum, which leads to washed-out bass and warbling in horns or bells. The MP3 compressor used also matters - some of the older opensource ones and the first public release of the Xing encoder tended to exaggerate this problem. Of course, the better your playback equipment is, the more likely you are to notice this stuff. Any file below 128kbps is going to have noticible artifacts, especially in electronic music where very "pure" synthetic waveforms are being used. My ears are too blown from years of unprotected concertgoing to find many problems with the 128k files, but lot of people will claim that your need to use 192k and up for "CD quality" audio. YMMV. -- Kevin | "I've always wanted to have a wonderful, beautiful Murphy | wife who loves me to death, and she's always | wanted to be an American, so it's working out | really well." - Emo Phillips --------------------------------------------------------------------- To unsubscribe, e-mail: idm-unsubscribe@hyperreal.org For additional commands, e-mail: idm-help@hyperreal.org