Knepper was quoted as saying ''in a lot of ways, [jazz is] just shallow, superficial and pyrotechnical.'' Maybe that's why it was so important to him to prove that jazz could be played that was not shallow, superficial and pyrotechnical for its own sake.
Piling on the ironies, although Knepper sounded great in any setting, I believe he was most expressive in the musical context provided by the man who assaulted him and almost ended his career: Charles Mingus. Mingus' music gave a kind of scope that freed Knepper. The stops, starts, changes of tempo and mood, freedom to explore less "refined" tonal directions, provided a dramatic stage on which Knepper thrived.
Yet, in 1981, Knepper told Downbeat: ''It was very depressing to think that I'm linked with this guy for the rest of my life."
I have no problem with the contradictory nature of all this. It gives the lie to the easy assumptions that people make about personality and art.
Before getting to Mingus music, let's start with Knepper in a more straight-ahead context, Here he is in a 1957 release, A Swinging Introduction from September 1957 with Knepper (tb), Gene Quill (as), Evans (p), Teddy Kotick (b) and Dannie Richmond (d). The tone is there-a good deal of vibrato; harmonically it's squarely in the bop idiom, but with some unusual interval leaps and a subtly dramatic quality.
Here he is in his first Mingus recording, Tijuana Moods, recorded the same year-1957. He responds well to this rhythmic environment, which is both more demanding and looser. He also begins to explore the trombone's tonal palette.
Here's Jimmy on Gentleman's Agreement (1983) with Danny RIchmond, drums, George Adams, tenor sax, High Lawson, piano. Mike RIchmond, bass. Knepper 's statement is solid and contains almost all the elements we find in the Mingus context. Still...
In this final tune, the title track from Tonight At Noon (1961), It sounds as if Knepper has completely internalized the resonance of this Mingus group. Everything he plays sounds like it comes from a complete emotional commitment.