CHARLES MINGUS, it should be pointed out right away, pushed himself beyond the outer limits.

He didn't want to be called a jazz musician even though he was one of the greatest bassists and composers of the idiom. The term "jazz" was degrading, he said.

Mingus also thought many of his colleagues relied too heavily on cliches, and on playing what audiences wanted. In his groups he needled musicians to stretch out beyond their capabilities.

Moreover, the musician deeply resented the restraints put on his artistic ambitions and social mobility, and he waged constant battle against real and imaginary foes. He lectured nightclub owners and audience, and wroter polemics.

Mingus, who died on Jan. 5 in Cuernavaca, Mexico, of amyotrophic lateral sclerosis, a muscular disease also known as Lou Gehrig's disease, was a baffling mixture of bellicosity and tenderness -- a callous taskmaster who was also an affectionate father figure. Above all, however, he was a gifted and innovative artist -- a technically dazzling instrumentalist and distinctive composer.

Before Mingus, the bass in jazz was largely a rhythm instrument. A smattering of bassists were excellent soloists, but their chief function was to keep time. In his case, while laying down a basic pulse, Mingus created counterlines to horn solos, making the bass a frontine instrument.

Mingus was probably the most iverse of modern jazz composers. His works were painted on broad canvases, reflecting the influence of the Afro-American church, early New Orleans music, European impressionism, programmatic sound effects and experimental improvisational techniques. He blended these disparate elements into musical statements of churning emotional power.

His compositions were marked by long, Iyrical themes such as the serpentine lines of "Goodbye Pork Pie Hat" and "Reincarnation of a Loverbird," paeans for Lester Young and Charlie Parker, respectively, or characterized by the turbulence and factiousness of "Haitian Fight Song" or "Meditations on Integration."

Mingus also had a fondness for the unexpected. In the church section of "Revelations, Part I," he suddenly shouts "Amen!" In the midst of "Cumbia & Jazz Fusion," his work combining North American and Colombian elements, he and drummer Dannie Richmond surge into a raucous vocal: "Who said Mama's little baby likes shortenin' bread?... That's some lie some white man upped said. Mama's little baby don't like no shortenin' bread. Mama's little baby likes truffles. Mama's little baby likes caviar. Mama's little baby likes all the fine things of life... Mama's little baby likes African gold mines. Mama's little baby likes African diamond mines..."

"He was not an ordinary musician," observes Julian Euell, who once played bass in a Mingus group and is now the Smithsonian Institution's assistnat secretary for public service.

"He was reminiscent of a Paul Robeson. I mean he went further than Charlie Parker and Dizzy Gillespie. Mingus always had a political perception of music. He was angry that this country had not recognized black musicians. And all the while he made a musical statement, he also made a social statement."

Mingus was not given to straight propagandizing, however. Art was always first, even when he was angriest.

In this connection, he mistrusted record producers, concert managers and nightclub owners. He tried operating a record company twice, but a lack of business skill derailed his attempts.

He was more successful, with Max Roach, in helping organize a rumpfestival at Cliff Walk Monor in protest of the 1960 Newport Jzz Festival. He and Roach thought the bookings of nonjazz performers such as Pat Suzuki and the Kingston Trio diluted the festival.

Saxophonist Buddy Collette, who knew the composer since they were schoolmates in the Watts section of Los Angeles at age 12 or 13, says Mingus' drive was so strong that "he was not a guy you'd ask to go to the theater because he'd be uncomfortable. He always thought about music. He used to wake me up early in the morning with a bass on his back, wanting to practice.

"I remember when he first started composing. He'd sit at the piano for hours. His first wife would take his meals to him. And after he finished at the piano, he'd practice his bass for six or seven hours.

"He was an insomniac. So he only slept about two or three hours a night.

"Mingus was also quick. He played cello in the school orchestra and wanted to learn bass. He and his father went to a pawn shop and traded the cello for a bass. Within three days he was ready to play the bass for a concert."

Mingus also spoke of his burning desire to master the bass. As a teen-ager studying with H. Reinschagen, a former bassist with the New York Philharmonic, Mingus said, "I'd practice the hardest things incesantly. The third finger is seldom used, so I used it all the time. What happened, however, is that for a while I concentrated on speed and technique almost as ends in themselves. I aimed at scaring all the other bass players."

Collette also remembers Mingus in the early 1940s as an eccentric dresser when most people in Los Angeles were conformists. He shaved his head and studied yoga.

Beneath his nonconformity, Mingus was always bothered by race, recalls Collette. His feelings about race surfaced in his outspokenness or his bristling music.

"He carried a great deal of anger," says Euell. "He challenged club owners and the system.Sometimes I was uncomfortable on the bandstand with him. Upi dodn't know what would happen."

On the other hand, Mingus possessed a streak of wild humor, often expressed in hyperbole. He was a man who could transform Jerome Kern's "All the Tings You Are" into his own composition, "All the Things you Could Be By Now if Sigmund Freud's Wife Was Your Mother."

Or one noisy Friday night at the nowdefunct Cafe Bohemia, Mingus held up his hand for silence and intoned:

"We have a new audience participation number. It's intended to make you feel inferior. Here's how it works. We play for four bars. Then you talk and laugh and break glasses for four bars, and then we play four again, and so on.

"The name of the song is 'Reverse Psychology.' Dig?"

Sometimes he'd wear a Chesterfield jacket, striped pants and bowler hat, carry a walking stick and ride in a rented Rolls Royce. These were times he called himself Baron Mingus.

Intertwined with all the hyperbole, bitterness, hostility and self-destructiveness of Mingus was a captivating tenderness. When President Carter embraced him at the White House Jazz Festival in June, Mingus sobbed.

Euell remembers him as being gentle and kind. "He used to call me on the phone and ask me to listen to music he was writing," says the Smithsonian official. "I wasn't a peer. I guess he thought of me as kind of a younger brother and he wanted to help me along."

The many sides of his personality colored his relations with his sidemen. "It was like a love-hate thing," recalls Euell. "He forced guys to play better by putting a lot of pressure on them. It got to be a personal thing. They didn't like it, but after they left the group they played better, and they appreciated him.

"He'd tell them, 'Don't play like Charlie Parker. He can do it better. Play yourself. Be an individual.'"

For Mingus, music was the paramount expression.

In a letter to Miles Davis, he wrote: "Just because I'm playing jazz, I don't forget about me. I play or write me, the way I feel, through jazz, or whatever. Music is, or was, a language of the emotions. If someone has been escaping reality, I don't expect him to dig my music... my music is alive and it's about the living and the dead, about good and evil. It's angry, yet it's real because it knows it's angry."