THE JAZZ TRIO was playing vintage Dylan tunes -- an odd choice. All those old pieces seemed to defy the kind of harmonic complexity that jazz demands. And here were saxophone, bass, and drums, playing "The Man in the Long Black Coat," "Percy's Song," and "My Back Pages." But the folk melodies fit, and the band played them with understated tenderness. The drummer in particular -- who provided the perfect mix of color and propulsion with each stroke -- was visibly focused in quiet concentration, his physical movements measured and precise as he squinted, grimaced, and occasionally smiled. He played several percussion instruments that were apparently of his own invention. One was a bound bunch of what looked like short, rough-cut bamboo sticks that he'd twist in his hands for their crunchy wooden sound. Most remarkable was what looked like a double frame -- like a small window frame -- joined at one end by hinges and laying flat on a small table. Held loosely in the top half of the frame by twine were rows of small wooden pegs. As the drummer opened and closed the frame, the rows of pegs created sounds that suggested variously the huffing of breath, the sound of the wind, or a small army on the march.

The music was compelling, but its interest was owed to more than sound. Musicians perform with all manner of facial and bodily expressions -- we all know the gesture of the power-chording rock guitarist, while some are so impassive when they play that they give nothing but notes. But this drummer played with serene contemplation, and his engagement with his material was transparent. It was like watching someone compose a poem on stage.

That was the drummer Michael Vatcher performing with Michael Moore's trio at the ICA a couple of months ago. Concert-goers are very familiar with these experiences -- when musicians' gestures are at one with their creations, or when those gestures overwhelm the music. In a stadium of 50,000 people, you'd better have mastered the grand gesture. But the smaller the venue, the more chance there is of being let in on the creative process, of experiencing what the critic Sanford Schwartz calls "the art presence." For me, that phrase suggests more than notes or text, but the sensation -- at least in concerts or live performances -- of a shared experience unfolding in real time.

More recently, I attended a small concert given by the pianist Hung-Kuan Chen. The situation was ideal -- a small room built specifically for the performance and recording of music, and a beautiful nine-foot Steinway grand. The coveted seats in piano recitals are those that look more or less over the pianist's shoulder so you can see his or her fingers on the keyboard. But at this concert, the audience of about 75 or so sat in an L-shaped configuration around the piano. My wife and I sat facing the piano -- and the pianist. I'm used to seeing musicians grimace in concentration, or play with their eyes closed, or, in the case of a pianist, look down at the keyboard or at sheet music. Chen, not overly demonstrative, did a bit of this, but he also had a tendency every once in a while to look up for a moment and then gaze off slightly to his left -- not the blank gaze of concentration, but a focused look, as though he were trying to remember something.

Now, anyone familiar with classical-music recitals knows that the memorization of a musical text has perils as deep as those facing an actor who steps on stage with hundreds of lines of dialogue in his head. Those looks of Chen's could have meant anything -- memory lapses, thinking ahead, or just trying to stay in the music of the moment. (He was playing pieces by Beethoven, Liszt, and Ravel -- all from memory.) But the look on Chen's face was not that of someone trying to remember something, but someone who had just remembered something -- something outside of, but not divorced from, the text. It was as though the music itself were a memory that he was having at that moment, and we were having it with him.

I think any of us who attend regular performances of dance, music, opera, or theater cherish moments like these. Maybe it's the way Fiona Shaw says "Ladies" when she addresses the chorus upon entering the first act of Medea. Or the way jazz singer Patricia Barber, in a recent Boston performance, playing and singing beautifully, lowered her head to the keyboard, turned slightly toward the audience, eyes closed, and said off-mike in a long, flat voice, "Fock!" Or the drummer in the jazz quartet Guaranteed Swahili, playing all night in tight, economical motions, his set arranged low around him, unscrewing the top nut on his ride cymbal almost before the last note of the band's last tune at the Lizard Lounge has faded, and before the band can play an encore.

Jon Garelick can be reached at jgarelick@phx.com.