easy search from yahoo.com http://www.mp3-faq.org/faq3.html
What's the Difference between Stereo, Joint-Stereo and Dual-Channel?
Joint-Stereo - This method of encoding combines duplicate (or
"perceptually similar") information from the Right and Left channels
in an effort to most efficiently compress the file. This way the
duplicate information is only encoded *once* instead of twice (one
time for each channel) and allows for more bits to be allocated to the
other non-duplicate information.
Th
