Maybe a BSG technologies QOL signal completion stage is what you need to reclaim the hidden info on the recordings . . .
I think of live not as reproduction but simply amplification (and perhaps distortion) of the voice. A good venue with good acoustics helps a lot, such as the Allen Room at Jazz at Lincoln Center here in NY. The type of music can make a difference too, as you suggest. Oops, break time's over. Back to work!
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