There are at least two, possible three or more, threads on QQ that have laid all of this information out already:
https://www.quadraphonicquad.com/forums/threads/decoding-deep-purple-machine-head.23780/post-430705https://www.quadraphonicquad.com/forums/threads/deep-purple-machine-head-sacd-help.34569/post-750870https://www.quadraphonicquad.com/fo...ad-mix-on-the-2003-emi-sacd.35401/post-752463https://www.quadraphonicquad.com/fo...ple-machine-head-cd-4-q8-qr.17210/post-630243https://www.quadraphonicquad.com/fo...achine-head-dvd-a-sacd-japan.4389/post-576015
So again, in brief:
There are three surround mixes (soon to be four, with Atmos)
Two are quad from the 1970s, the UK and the US mixes. As mixes they are quite different and choice is subjective. The 'issues' mentioned are likely
- some missing parts/edits in the UK quad, though sound quality is considered good. Once thought by some to have incorrect rear channel assignment, but this has been debunked by steelydave on QQ. This quad mix has been released on SACD and DVD.
- sound quality of the available US quad digitizations done by fans, though this may improve when the official release on the SDE becomes available
The third is the 5.1 remix from 2001, which some consider a 'tame' mix, and which I consider to have excess reverb, though sound quality is otherwise great. This has been released on DVDA and SACD and three 'bonus tracks' from it keep getting tacked on to other releases.
for the love of all that is purple, can this info be made a 'sticky' somewhere on QQ with a loud title, so we don't retread this ground over and over?
And also , yes DWEEZIL ZAPPA MADE THE ATMOS MIX.