Les McCann,Thomas Caldwell a prolific and influential musician and recording artist who helped found the soul-jazz genre and became a favorite source for sampling by Dr. Dre, A Tribe Called Quest and hundreds of other hip-hop performers, has died. He was 88.

McCann died Friday in Los Angeles a week after being hospitalized with pneumonia, according to his longtime manager and producer, Alan Abrahams.

A Lexington, Kentucky, native, McCann was a vocalist and self-taught pianist whose career dated back to the 1950s, when he won a singing contest while serving in the U.S. Navy and appeared on “The Ed Sullivan Show,” the top variety program of its time. With admirers including Quincy Jones and Miles Davis, he went on tour worldwide and released dozens of albums, starting in 1960 with “Les McCann Ltd. Plays the Truth.”

He was best known for “Compared to What,” a funky protest song on which he first teamed up with his future musical partner, saxophonist Eddie Harris. Written by Eugene McDaniels and recorded live at the 1968 Monteaux Jazz Festival, “Compared to What” blended jazzy riffs and McCann’s gospel-style vocals. The song condemned war, greed and injustice with such couplets as “Nobody gives us rhyme or reason/Have one doubt, they call it treason.”

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Among those covering “Compared to What” was Roberta Flack, a McCann protégé whose career he helped launch by setting up an audition with Atlantic Records. McCann was a pioneer in merging jazz with soul and funk. He would record with Flack and tour with such popular musicians as Wilson Pickett, Santana and the Staples Singers.

His other albums included “Talk to the People” (1972), “Layers” (1973) and “Another Beginning” (1974). Last month, Resonance Records issued “Never A Dull Moment! - Live from Coast to Coast (1966-1967).”