Ask saxophonist Sam Rivers about his impending 80th birthday on Thursday and he just laughs.
"I don't think about it much," he says. "I'm feeling fine and my son is a doctor. That always helps."
Ask about his music, however, and the epigrammatic responses quickly expand into thoughtful explanations of his lifelong fascination with the improvisational processes of jazz.
"I've been through a lot of different phases," Rivers says. "I've played bebop and I've played avant-garde, and I'm still learning something new about it every day."
"Still learning" to the extent that the trio he brings to the Jazz Bakery tonight for a six-night run will incorporate sounds, rhythms and improvisational techniques stretching across stylistic boundaries, embracing every segment of his long career.
"Spontaneous creativity" is how he describes the music he performs with bassist Doug Matthews and drummer Anthony Coles (with each playing three or four other instruments). It is jazz in which preset harmony and melody have been abandoned in favor of completely spontaneous improvisation -- jazz not based on anything.
"I've been doing spontaneous creativity so long that it's like second nature," Rivers says from his Florida home. "Basically what it means is that we create everything on the spot -- the melody, everything, even the rhythms."
What is an audience to make of jazz without the familiar reference points of harmonies from standard tunes and the blues?
"At the bottom line, art is all about feeling and emotion," he explains. "In rock, they substitute volume for emotion. We try to do it with color, tempo and so forth."
The keystone of Rivers' fascination with spontaneous creativity is the '60s, when jazz -- and popular music and the nation -- went through a series of titanic upheavals. Ornette Coleman, Albert Ayler, Cecil Taylor and others proposed new ways of approaching jazz, often abandoning the art's long association with the process of theme and invented variations.
"When you think about it," he says, "[Charles] Mingus, Cecil and Ornette were already stretching out before the '60s. They really led the way into the rebellion and the iconoclasm in the music that happened in the '60s.
"Not only in jazz but in the other arts as well. Changes everywhere -- painting, photography, writing, pop music ... think about Jimi Hendrix -- directly reflecting everything that was happening."
Oklahoma-born Rivers was working with Miles Davis in the early '60s. By middecade he was involved with activities surrounding Bill Dixon's edgy Jazz Composers Guild.
"People couldn't quite figure out where I was coming from," he says. "When I came to New York, I was playing with Miles Davis. Then I went with Cecil Taylor, and everybody seemed to think that was what I did. Then, later, when I went with Dizzy Gillespie, they said, 'What is Sam Rivers the avant-gardist doing with Dizzy?' But I think I really benefited from the different things I did. I'm one of the few players who felt comfortable about crossing back and forth."
His own recordings began to be released in the mid-'70s, including the highly regarded "Fuchsia Swing Song." In 1970, he and his wife, Beatrice, founded Studio Rivbea, a pioneering location in the Manhattan loft-jazz scene that became a vital part of cutting-edge jazz for the balance of the century.
In the '80s, after returning from yet another lengthy tour -- this time with Gillespie -- Rivers decided he'd had his New York experience and began to think about moving. Serendipitously, he received an offer to move to Orlando, Fla.
"I was offered an orchestra to work with," he says, "to play my music, try new things, the sort of orchestra we'd had at the studio. And sure enough here I am, pretty much working with the same musicians I've had for more than a decade. They're all teachers at various universities along with some studio players and some musicians from Disney too."
"It's a good situation, very conducive to my 'creative posture,' " he adds with another laugh. "I get a lot of work done, I have a group of good players that play my music every Wednesday night and I occasionally get out on tour with my trio."
Given the effect that the '60s had on his creative development, has Rivers' comfortable life in Florida affected his interest in stretching the envelope?
"Not at all," he says. "The orientation may be different, but creativity is creativity. You start with nothing, no plan, and you make something out of it. Back in the '70s, I had a group -- with [bassist] Dave Holland and [guitarist] Barry Altschul doing exactly that: performing 2 1/2 hours with no music, just spontaneous creativity, making cohesive performances. And that's still where my heart is. Sometimes I do it on the spot with the trio. Sometimes I write it down for a large group.
"After all," Rivers concludes, "composing -- by any composer -- is really a matter of writing down the improvisations that you hear in your head. And those spontaneous creations just keep on coming."
The Sam Rivers Trio
Where: The Jazz Bakery, 3233 Helms Ave., L.A.
When: Tonight-Sunday, 8 and 9:30 p.m.
Contact: (310) 271-9039