For all those out there that keep ripping and sharing in Joint Stereo, here is the new UK No.1 30.08.09 in true stereo Dual Channel
If you are interested, the 3 encoding formats are:-
1) Joint Stereo shares certain bits between high frequency left and right channels. This improves compression efficiency at a slight loss of stereo separation.
2) Stereo includes two independent channels. The total bit rate remains constant, but the split between the channels can vary. The Encoder uses this flexibility to improve quality by allocating more bits to the channel with the more dynamic signal. Use the Stereo setting for best quality stereo audio at higher bit rates.
3) Dual Stereo/Dual Channel includes two completely independent channels (left/right)
This description is from Jackie Franck, one of the pioneers of MP3 conversion and the author of Audiograbber, the definitive MP3 converter from the last century. He now is part of the dB Poweramp team, the definitive audio converter from THIS century.