You can get down to the ass scratching in the orchestra pit with Otto Klemper doing Beethoven, or the running conversation in the jazz set with a few hundred dollars of used AR equipment. The classic take was Miles Davis telling Rudy Van Gelder the sound engineer, "Hey, Rudy, put this on the record, all of it." It was the 1953 release of The Man I Love which also had the best version of Round Midnight. I've still got the album bought used in Iowa City in 1964.
^^^^^ CB: Thelonius Monk yells out "Coltrane, Coltrane" at the start of a solo to rouse the nodding Trane. Can't remember the song. Errol Garner is always "mumble-hums" through his stuff. I think Pablo Casals might hum some , too.