RE: The mixes themselves and the inclusion of outtakes or outtake-elements.
As we all know - Quadraphonic was often thought of as the first foray into the world of Alternate Masters, Extra Tracks and Other Bonus Material that we know today due to the highermarket saturation of multi-channel audio, via DVD and Blu-Ray compared to the LP, Quad Reel and Q-8.
And just like in DVD and Blu-Ray productions today, new 70's Quad remixes of material from the mid-to-late 60's often featured previously-unheard portions of the original session tape such as an extended intro or outro, a lengthened or alternate solo, or other additional sweetening which was recorded, but deemed unsuitable for the final record for one reason or the other.
Similar to whole songs ``left on the cutting room floor'' which appear on modern box sets after an artist passes away these ``outtake elements'' often change the entire mood or presentation of the piece - and may have been why they were originally left off.
But now - similar to re-assembling a classic film with supplemetal material that was also deemed unsuitable for the original release for one reason or the other - it's interesting to see and/or hear what some of the original ideas came from which had been bandied about in the studio by artists and producers - and then hear the final form these ideas took on the original record.
Who can forget the proposal scene with Judy Garland and James Mason in
A Star is Born (1954) that we had to wait 30 years to see?
An alternate master shot of the intro that was itself deemed too long from a number that ended up being cut entirely
http://www.youtube.com/watch?v=6_VhF87MuqE and with the closeups
http://www.youtube.com/watch?v=K26MNumr9po.
Look at the feel of the outtake introduction - it's done in a very effortless even offhand manner compared to the take they used. She looks bored and tired. This performance is phoned in and suggests that Esther really didn't care one way or another about anything she was doing or anybody she was around. Couple that with the proposal half of the scene and it's almost jarring when she says Yes. Compare that with the take they used - and she almost spoon-feeds you the plot there for four minutes and a half.
Compare that to the intro they used - filmed a week later - and the performance is alive and electric. Me - I like the outtake intro better - for just exactly that reason - that the viewer is then surprised when she takes Norman up on his proposal later..
A whole performance as well as alternates. Just thrown into the garbage like that for ``lack of space'' in the vault because some cubicle warrior got a hair under their collar. Saved from an untimely demise by a crotchety old codger who used to sweep up after productions.
Regarding remixing from original sources and the quality or lack thereof:
The new mix might SOUND like 5.1 - but that's just because of a little bit of electronic trickery. In 1968 very few rock-and-roll acts were recorded on anything more than 3 or 4 track half-inch tape. The vast majority of 8-track 1-inch sessions held at any major label in those days was reserved for huge-budget classical and Broadway acts.
(The following is a brief primer of 60's recording practices in case there's any newbies reading this. Everybody else - skip to the bottom.)
So - with only 3 or 4 tracks to work with - about the only thing a modern mixing engineer can do is to take different recorded elements and pan them to the different tracks and back, or else take a Left-minus-Center and a Center-minus Right signal out and use that as the ``surrounds'' - or do the same thing three times in the case of a 4-track.
The only two saving elements that could give you any more elements than that is:
The best arrangers of the period knew that they only had a small number of tracks to work with - and arranged their instrumental assignments to the three or four tracks accordingly to maximize the use - merging more than one instrument which didn't play at the same time onto one track.
Since arrangers of the period also usually left a bar or two of silence inbetween where one instrument on a track left off and another started, once in awhile a modern engineer can separate out those passages, isolate them on their own digital tracks and manipulate as needed.
Since most rock and pop records of the late 60's and early 70's still came out in mono, a more common way to do that was - if a project happened to have one or more overdub sessions attached to it.
Since, as we said - eight-track one-inch sessions in the 60's for rock and pop acts were kind of hard to come by if not impossible - the only other thing to do would be to split the session up over multiple reels of 3-track or 4-track in the following manner:
1. The basic band tracks would be recorded on one reel of 3 or 4 tracks.
2. They'd go on recording until they got a take they liked.
3. That take would be mixed to mono and laid onto a second reel on a second machine leaving two or three tracks open.
4. Additional soloists, sidemen, effects and sometimes background vocals would be added.
5. The additions would then be mixed to mono on their own track and flown over along with a second-generation copy of the original session to a third reel being recorded back on the first machine, leaving one or two open (depending on 3-track or 4-track).
6. Then the lead vocalist or instrumentalist and/or their track harmonizing with themselves would be added last and then
7. the final mono (or even stereo) mixdown would be performed from that third-stage tape.
So if you ever run across a stereo mix that has the lead in the center, basic tracks on the left and sweetening on the right - that's why - and was about all they could do to remix in stereo for productions that did not have stereo in mind when they were recorded.
Now, in the 60's and 70's, even up to the late 90's, technology hadn't caught up to the point yet where an engineer could successfully lift tracks from the first and second stage tapes, sync them up to the third stage and remix for stereo.
Which is why for a lot of years, remix engineers would simply take just the isolated vocal or soloist track off the third stage tape, write and record a whole new session of digital backing tracks, and then remix to stereo.
Well a few bright young men in the early 2000's discovered that all these different stage-tapes could be locked up to themselves similar to the way film tracks on different media are locked up. Unfortunately however, in the early days of digital sync, it was all manual, often requiring hundreds of hours and thousands of edits just to be able to sync up the stage tapes to one three-minute song sufficiently enough to where the record-buying public would never know the number would have been re-assembled from so many sources.
Nowadays it's a lot easier - though still far from perfect.
All modern magnetic tape made after 1946 is recorded with a supersonic bias tone on the original tape to help increase the fidelity of the recording. However, this bias tone does not carry over with the music when dubs are made.
So, the modern engineer with access to all the original session masters can now send this bias tone through a reader, which will then correct for most of the miniscule and continuously-variable speed deviations inherent in the original recording, allowing it to very closely resemble sprocketed film for being able to maintain a much closer approxximation of rock-solid sync than you could ever get by hand, even after transferring ``wild'' (without sync) and spending hundreds of hours in front of the computer trying to correct for all the speed variations.
Once that's done, then the modern engineer can remix, just as if the original session had been recorded on 1-inch 8-track tape - and none but the most discerning listener will be able to tell that this new production was achieved in such a manner.
The definition of the terms of Digitally Extracted Stereo or Digitally Constructed Stereo which are used to describe the processes, can be found in a brief primer which can be found at the following link over on the BSN Stereo Chat forums to which many QQ members also belong.
http://bsnpubs.websitetoolbox.com/post/Unconventional-Stereo-Terminology-216267
For the newbies, membership is free, however board threads and posts are no longer visible to non-members due to the high volume of unrelated ``browser'' traffic that has occurred, driving up the cost of maintaining the website, which Mike does out of his own pocket as a community service.