My friends and I often look over at each other while listening and say "these guys knew what they were doing" (meaning the engineers recording skills).
Perhaps better mastering to retain dynamic range was/is part of it, never thought about that. I don't think superior imaging, proper choice of mic type and placement is related to this issue.
This DVD
Buy it NOW.
Video Quality is scary, but the sound quality is quite enjoyable.
He plays one of the largest pianos I have ever seen (don't know which Bosendorfer model)
They have 6 mics on that piano, and his separate vocal mic.
Interestingly, at some point, one of the recording staff creeps up and changes his vocal mic, his voice changes for the better (he talks, no singing).
I shake my head at such excellent recording skills.