Rudy Van Gelder, an audio engineer whose work with Miles Davis, John Coltrane and numerous other musicians helped define the sound of jazz on record, died on Thursday at his home, which doubled as his studio, in Englewood Cliffs, N.J. He was 91.

His death was confirmed by his assistant, Maureen Sickler.

Mr. Van Gelder, as he took pains to explain to interviewers, was an engineer and not a producer. He was not in charge of the sessions he recorded; he did not hire the musicians or play any role in choosing the repertoire. But he had the final say in what the records sounded like, and he was, in the view of countless producers, musicians and listeners, better at that than anyone.

The many albums he engineered for Blue Note, Prestige, Impulse and other labels in the 1950s and ’60s included acknowledged classics like Coltrane’s “A Love Supreme,” Davis’s “Walkin’,” Herbie Hancock’s “Maiden Voyage,” Sonny Rollins’s “Saxophone Colossus” and Horace Silver’s “Song for My Father.”

In the 1970s he worked primarily for CTI Records, the most commercially successful jazz label of the period, where his discography included hit albums like Esther Phillips’s “What a Diff’rence a Day Makes” and Grover Washington Jr.’s “Mister Magic.”