The days have passed when jazz musicians would say, "If you have to ask what jazz is, you'll never know."

Today, more and more players enjoy sharing their insights into the music. And one of the most articulate is Wynton Marsalis.

Marsalis and his five-man band are in town at the Zephyr for a two-day stop. And if the opening set on Tuesday was any indication, he plans to hang a performance on the wall for other traveling jazz musicians to shoot at.

Featuring keyboards, bass, drums, alto and tenor sax and the ring leader on trumpet, the Marsalis sextet takes itself - and its music - very seriously. No novelty here, and nothing derivative. This is mainstream jazz coaxed out onto the edge.

Numbers on Tuesday ranged from an original composition that flirted with atonality and syncopation without coming apart at the seams, to a wrenching rendition of Gershwin's classic, "Embraceable You."

It's been said there are only three types of true genius: musical, mathematical and military. Perhaps musical genius entails composing material that is at once completely recognizable, yet completely fresh. The Marsalis style hovers in that territory.

For Wynton Marsalis, being a young trumpet player in the era of Louis Armstrong must have been similar to being a young poet in the era of Eliot. Novices had two choices: (a) React against the master, or (b) hope you're strong enough to absorb the influences without losing your own voice.

My guess is Marsalis was helped with plan (b) by his rigid classical training. Where many trumpet players go for yak and sass (a style that's responsible for our English adjective "brassy"), Marsalis tends to play in clean, precise lines. Some of his more inventive embellishments, in fact, have the eeriness of scale exercises done on a trumpet from Mars. He doesn't gloss notes, and he never confuses dexterity with virtuosity. Some of his finest moments come when he's playing simple intervals.

Yet what keeps jazz fans in his corner isn't simply technique. Like the jazz greats, he has that knack for pleasing listeners intellectually, then bypassing their hearts to hit them at gut level.

No mean trick.

Needless to say, Marsalis took a few moments Tuesday night to chat. He compared - or better - contrasted Salt Lake with New York and showed the earnest quality that has made him a no-nonsense spokesman for his music. At one point he asked the crowd to please refrain from talking louder than the band played. The hard floors at the Zephyr, he said, tended to amplify the audience.

As for the Zephyr Club, bringing in Wynton Marsalis is an obvious coup. Surprisingly, neither show Tuesday was sold out. It seems to be the lot of Salt Lake City to always appear both cosmopolitan and provincial at the same time.

Still, those who did show for the show will likely be talking it up for some time.

And that can only be good for jazz in this state.

And be good for the state of jazz.