Is the SDOTM SACD mix that much different then the Parsons Quad mix...I never heard the SACD mix.
Oooh... dangerous question!
There seem to be a number of camps that prefer different versions. My first experience of a multi-channel DSOTM was the Parsons quad mix and it was my only experience of it for some while. I read many reports of the SACD mix not being up to scratch and I only got that disc 6 months ago or so. I've never experienced the Blu Ray collection of mixes, which would be a good way of listening to all the available mixes, but I guess it all boils down to personal preference. Allegedly, the band didn't like the quad mix that Parsons did and they then commissioned their current engineer, James Guthrie, to do a 5.1 mix for the SACD release in 2003.
I suppose comparing a 1973 quad mix to a 5.1 mix done 30 years later is probably a bit unfair. I'm certain that had 5.1 been around in '73. Parsons would've done a sterling job in that format. Parsons has also claimed, naturally, that he prefers the quad mix, and to be fair to him, he was involved with the creation of the album itself, so I'd have to defer to his vastly superior knowledge of the material and the creative force behind it.
As for differences, well, one is a 4.0 mix, the other is 5.1. The quad mix I have has been enhanced to utilise the LFE channel. I guess, like most things, it's down to personal taste. You pick the mix you prefer, be it stereo, quad or 5.1
You can find lots of interesting DSOTM multi-channel history and info here...
https://www.quadraphonicquad.com/QQ-PFQ.htm
It's still a remarkable album and spookily, today is the 5th anniversary of Richard Wright's untimely passing
