Before anyone suggests it, I have not gotten confused by the vinyl "CD-4" quadrophonic records of the 1970s. Rather, I noticed some time back that the official Phillips Compact Disc-Digital Audio specification provided for a high-bit-rate quad mode in which four channels of 16/4401/75 EIAJ digital audio would be output simultaneously, at the cost of reducing play time to about 5/8 of normal [which is not so big a deal -- after all, how many 70+ minute CDs are there?]. My question is, is anyone aware of any actual production in this format, of any software package which would permit producing them for oneself, and most to the point any hardware which could play them back? While some CD players have duplicate line outputs, I have never seen four discrete line outputs; one would hope an SPDIF connection would pass a signal written into the CDDA standard, but I'm not confident of that; even if so I don't know if any CD player made would synch to the bitstream, or if a multichannel amp recieving it would handle the four channels properly. Can you help me?Thank you.