My Fair Lady (1964)

Not a comparison, but the audio on the new blu-ray sounds fabulous, and the following information from Robert A. Harris is reassuring:

There were originally three sets of tracks. A monaural mix for 35mm optical prints, a 4-track mix for magnetic 35mm prints, and a 6-track 70mm fully discreet mix.

The 70mm mag tracks are set up for standard Todd-AO audio with five discreet channels behind the screen, plus a sixth effects channel, also discreet, used for almost the entire show.

The new 7.1 (actually 7.0), derived from the original 6-track fullcoat masters, replicates the original mix as closely as possible. A great deal of effort went into extracting the high frequency information lacking in earlier incarnations. The new audio master fully reproduces the entire audio spectrum, as heard in 1964.

The audio situation was also problematic. We had found about half of the four-track magnetic full coat, and the entire six-track original less one reel, which had been duplicated. There was no ex copy, and those tracks were getting old and vinegary. The first thing we did with the original audio was to make an ex copy of the original show and then the re-recording we did was made from that ex copy. So the reality of the situation was the audio we ended up with in 1994 as our master was third generation at best and fourth generation for one reel…and what people were hearing on the 70mm prints at that point were fourth and fifth generation. So audio was affected. It sounded great but it could have been better. 

In 1994 we had taken all of the audio elements and done preservation via a two-inch tape, but in 2014 we ran into problems. It seems there was a bad run of tape and they would not run without being baked - which is the way that you get old tapes to run. And basically, in league with CBS, which was extremely keen about asset protection, we decided to go back to all of the original audio materials which we were doing anyway for the six track, but to take all of the quarter inch, anything that was saved back in 1994, rehearsal audio, Audrey Hepburn’s vocals, Marni Nixon's tests - all of that were now saved again as data digitally.

One of the things that had changed was that Mags had started to go slightly more vinegar, so we had to try to get an audio image harvested from those. For that we went to a company called Audio Mechanics, and they did a wonderful job. Nick Bergh (of Endpoint Audio Labs) did the actual transfers from the originals, on special equipment he’d created for shrunken, vinegary mag. We were able to take those original six tracks from 1964 less the one that was probably made around 1970 and harvest the audio information from those in 96k, and did a re-recording in 96k. Being that it's all digital there's zero loss. So what people are going to hear on the new CBS Paramount Blu-ray is a representation of the original track from the original 1964 full coat mags. They will be heard for the first time in 50 years, including one anomaly that we call the “ghost on the stairway,” which is a slight echo and lasts only a second or two, in the sequence before the intermission. In the past, it was hidden by the number of generations the audio had gone through, but now you can hear it and we felt it was there, we're going to leave it.

12/5/2023: The UHD sounds great. Its frequency response is comparable to, if not better than, the 1996 Fox LaserDisc [0897385].