http://www.mp3-box.org/mp3-quality-bitrate/

Quality question! MP3 to CD, Back To MP3?
I have a bunch of mp3s i ripped with a bitrate of 360, and i want them down to 128 for storge reasons, i want more to fit on my mp3 player
the method im using is:
burn mp3s to vital drive
& repripping them in WMP!
the resulting mp3 is now 128!
im not so much bothered about the quailty change between 360 and 128… what i wanna know is does this precess MP3>CD>MP3 degrade the quality even more? more so them ripping direct from the original CD to 128 mp3s!
thanks in advance
Theoretically, since MP3′s are a “lossy” compression method. MP3>CD>MP3 should degrade the quality more than ripping direct from the origial CD to 128. However, I’d try both methods on one or two tracks and see if I could tell the difference. If I couldn’t, then I’d use whatever method was easier.
Mp3 Quality bit rate – Demo’ed 20Kbps mp3 – 24bit 96k Wav compare