@mrdecibel
What I find the engineers, producers and the artists do right, and this requires a very fine ear, is the ability to take each individual track (studio recordings specifically) and synchronize it all, resembling each performer playing live, together, in sync....
Ah, but that’s the complete opposite of what Mercury did for the Living Presence series!
When you have a full orchestra of say 100 players, it is impossible to individually place a microphone for each player. Mercury took the opposite approach and just used three microphones in a line, for left, centre and right. These were mixed down for stereo records and later for CDs by adding the centre signal to both left and right channels. Much later, their SACD releases contained all three original channels but as DSD rather than PCM. (When I play the SACDs, my preprocessor adds the centre channel to left and right because I chose not to use a centre speaker)
Once Mercury had the microphones set up and the recording equipment (either tape or film) set for maximum volume, they did no further mixing or synchronisation. The conductor and orchestra did the rest, with a contribution from the venue!
So the recording is an unadulterated version of a real performance from a listening point just back and slightly above the conductor. Regular concert goers quickly learn what a real unadulterated orchestra sounds like in a real acoustic. The recording engineers for Mercury, and these days for 2L, don’t interfere in any way with the artistry of the performance, once they have the equipment working properly!
I very nearly attended a Mercury original performance in 1962, when to quote Mercury’s notes, "Antal Dorati ... electrified a capacity audience at London’s Royal Festival Hall with a stunning performance of Bartok’s Bluebeard’s Castle." which was sung in Hungarian. I still remember the soprano Olga Szonyi cutting through the entire orchestra towards the agonising end. Mercury shortly afterwards hired the Watford Town Hall for a recorded re-run, using 35-mm film as the sound medium.
This performance has just been re-released (again) in March 2025 ...