Not like it is the authoritative work on the subject, but the full UL page I referred to is here . It does have a little more info about some of the other design/density considerations.

In the end, given the haze of history, I think I'd agree with Tony that the "9th" might have been a factor but was likely not *the* factor as its near-UL status might suggest. That doesn't seem inconsistent with what that gent Doi said.

Also, WRT that whole Von Karajan thing (and maybe Doug has an opinion on this) my memory is that when CDs were *almost* on the market (they were building like a total of 2 pressing plants) it seemed like there was a bigger stake for classical labels -- like who cared what the quality of rock-and-roll records was like, relatively speaking? I could see DG and others having a pretty active lobby at Sony/Philips. Plus, I don't think Von Karajan was known for keeping his mouth shut.

[edit: "Doi", not "Toi". Also, I was thinking H Von Karajan was on Deutsche Grammaphon, but as the UL page points out, it was Polygram that was (still is??) a Philips subsidiary]