Just to clarify, I did not imply that it's not a quad mix.... but the quad LP of Live It Up was a genuine remix with instruments isolated in the rears. I remember vocals popping up in the rears during "Brown-Eyed Girl" and a guitar in one of the back corners towards the end of "Ain't I Been Good To You".
T-Neck PZQ/ZAQ 33070 from 1974. Side 1: Live It Up (Part 1 & 2) Brown Eyed Girl Need a Little Taste of Love Lover's Eye Side 2: Midnight Sky (Part 1 & 2) Hello It's Me Ain't I Been Good to You (Part 1 & 2) On the Q8, "Brown Eyed Girl" and "Hello It's Me" are swapped to even out the program...www.quadraphonicquad.com
But there's a night and day difference between the 3 discrete examples that I mentioned, versus the other 2.
I checked Browned Eyed Girl, if I listen to the rear tracks only -- it sounds really,really bad, distorted, damaged.
And although it does have the backup vocals popping up in the rears as you mentioned, it's not discrete.
I do not know if it's the same version that you're referring to.
The rears on the title track are not as bad, but it still sounds processed, and again, not discrete.