This is purely a matter of curiosity. When DVDs first appeared, it was apparent that they had a perfectly acceptable audio output for the vast majority of consumers. Having persuaded consumers to buy home theatre systems, why didn't the companies simply release re-mixed multi-channel albums on ordinary DVDs? In that way, nobody needed to buy SACD or DVD-A compatible players, people were dealing with a familiar technology, and the sound was perfectly okay. Instead, we had all this fuss over SACD and DVD-A, which, as we've seen, has meant that neither format has exactly prospered. And as a result, multi-channel audio remains a niche market. Now before anyone points out that both SACD and VDD-A have better sound quality - yes, I know they have. But even on a good system, the different isn't that big a leap from DVD, and on the average consumer's system, I seriously doubt if they'd notice a difference in the normal run of things. So why on earth didn't companies just stick with DVD?