Art Davis, a genre-hopping double bassist who played both classical and jazz music, has died at age 73.

Davis died of a heart attack Sunday at his home in Long Beach, Calif., his son Kimaili Davis said.

Davis is best known for his collaboration with John Coltrane, performing on the albums Ascension, The Africa/Brass Sessions Vol. 1 and 2 and Ole Coltrane.

Coltrane considered Davis his favourite bassist. Jazz critic Nat Hentoff described Davis as "an astonishing player" and "beyond category."

Davis played with with a long and varied list of artists, including Thelonious Monk, Duke Ellington, Rahsaan Roland Kirk, Louis Armstrong, Judy Garland, John Denver, the trio Peter, Paul and Mary and Bob Dylan.

In the world of classical music, he was known for speaking up about racism, and for launching a legal case that led to increased use of the so-called blind audition, in which musicians are heard but not seen by those evaluating them for jobs.

Davis was blacklisted by the music industry in the 1970s after he filed a racial discrimination case against the New York Philharmonic.

Like other black musicians who challenged hiring practices, he found it difficult to get work.

"I lost 10 years out of my life," he recalled in a 2002 interview.

His response was to change careers. He returned to school to earn a doctorate in clinical psychology and started a practice.

For the rest of his career, he balanced performance dates with appointments to see patients.

Davis was born Dec. 3, 1933, in Harrisburg, Pa. He began studying piano at age five and played tuba in high school, as it was the only instrument available.

Eventually, he decided on a career in music and chose the double bass, believing it would present more opportunities. He studied with the principal double bassist at the Philadelphia Orchestra at age 17.

But when he auditioned for his hometown symphony, the audition committee was so harsh and demanding that the conductor Edwin MacArthur questioned their objectivity.

In an article in Double Bassist magazine, Davis recalled this early encounter with racism in the music industry.

"The answer was, 'Well, he's coloured,' and there was silence," he said. "Finally MacArthur burst out, 'If you don't want him, then you don't want me.' So they quickly got together and accepted me."

Davis won a scholarship to the Manhattan School of Music and the Juilliard School of Music.

Jazz movement

At night he played jazz in New York clubs, meeting Coltrane in the late 1950s in a jazz club in Harlem.

A few years later, when Coltrane was building his quartet, he invited Davis to join, but he did not want to tour and declined.

Davis's recording debut came in 1958 at the Newport Jazz Festival, with Max Roach's group that included the legendary Booker Little and George Coleman.

In a posting on his website, Davis describes the double bass as "the backbone of the band," and says it should "inspire the group by proposing harmonic information with a certain sound quality and rhythmic impulses."

Davis was known for mastery of his instrument. He pioneered a fingering technique for the bass and wrote The Arthur Davis System for Double Bass.

In 1959, Davis toured for two years with Dizzy Gillespie's band, then moved to New York and freelanced.

In 1961 he became the second African-American member of the NBC Staff Orchestra, working regularly on the Merv Griffin, Jack Paar and Johnny Carson shows.

He moved to Los Angeles to start his psychology practice.

Davis worked both classical and jazz gigs, telling Double Bassist "It all sounded good to me."

He taught at University of California at Irvine for two years and, until recently, was a part-time music instructor at Orange Coast College in Costa Mesa.

Davis is survived by two sons and a daughter. His wife Gladys died in 1995.

With files from the Associated Press