Originally Posted by Haggar
Instead of comparing the quality of recordings with other recordings, shouldn't the real comparison be with the actual performance of the music that is being recorded?
In principle, yes. In practice, this is pretty problematic.
The first issue is venue. Recording studios often have their own unique acoustics that ordinary people can't visit. Also many live performances occur in places that the average listener will never visit, whether it be the Musikverein in Vienna or some concert arena in London. Also, the room in which you're playing a recorded performance (like your living room) may have vastly different acoustics than where it was recorded.
The second issue is the performance itself. Each performance, whether it be live or a studio recording is a unique performance. For example, take a simple piece that may have been recorded several times over a performer's career, like Arthur Rubinstein playing a Chopin nocturne or Miles Davis playing "Kind of Blue."
I've been to plenty of live rock/pop concerts where the songs played are considerably different than the studio versions. As a matter of fact, the artist often wants the live performance to be different than the studio recording. That's part of the draw of a live rock/pop performance. For classical performances, the nuances are far more subtle, but they are there as well.
If one really wants to judge recordings to actual performances, one is pretty limited in the type of material that can be used for the assessment. Basically, it will come down to simple vocal music and/or a small number of unamplified musical instruments: things like piano recitals, violin sonatas, a cappella choral music, acoustic guitar/vocals, etc. by living artists who are still performing.
For example, I can assess a Murray Perahia recording of Bach solo piano works because he still performs live and I know what a piano sounds like because I have sat down in front of one and played.
Once you get into archival/historic recordings, all bets are off the table since the original performer is no longer around and typically the original recording shows its age in terms of its acoustic limitations. Maybe Murray Perahia could play some Chopin on Artur Rubinstein's piano, but you can't really compare the live Perahia performance with the historic Rubinstein recording.