...and Martin would work with the engineer, such as Norman Smith (who eventually found his way onto the early Pink Floyd albums).

The way they mixed stereo back then (vocals on one channel, the band on the other) was the way most pop and rock & roll were mixed at the time. Jazz, on the other hand, had had a hand in stereo mixing for awhile before the rock & roll world was able to catch up.

As stereo phonographs got cheaper, and more people listening to records in stereo than in mono, it eliminated the need to do two separate mixes. One instance in where Martin changed his production and mixing technique was when he heard a foreign version of SGT. PEPPER from Asia (I want to say Singapore). He received a copy of the album, but the EMI plant in Singapore pressed the record wrong. When he played "When I'm Sixty-Four", all he could hear was Paul's reverbed vocal. In other words, they isolated the side of the stereo track which had Paul's echoed voice, and not his main voice. He then realized that for the future, all vocals should be centered in the mix to prevent that from happening again.

The main task of mixing and editing was generally left to George Martin. Think of the GET BACK sessions, and how they had abandoned it. They initially gave the task to Glyn Johns, whose mixes were good but then the plans to release them were cancelled. That's why the task of mixing the album was given to Phil Spector.

They may have had a few suggestions, but they left those duties to Martin and the engineers.


===
"I love how some hip-hop dudes think it's perfectly normal to rock huge diamonds and oversized pink clothing but "soft" if you eat a girl out." - discjockingmost
===