The late Frank Zappa famously titled one of his records "Shut Up 'N Play Yer Guitar." Pretty early on during "Touch the Sound," a documentary about the Scottish-born percussionist Evelyn Glennie, I wanted to shout: "Stop talking and go bang something!"

Glennie, now 40, is a remarkable talent, a woman with a marked hearing impairment, which developed in late childhood, who never let a potentially insurmountable obstacle keep her from becoming an important and successful classical artist. "Touch the Sound" is at its best when Glennie is actively engaged in making music, whether by herself on a snare drum in the "great indoors" of Manhattan's Grand Central Terminal, in an improvised duet with guitarist Fred Frith or grooving on a rooftop with a funk drummer.

Unfortunately, a good deal of "Touch the Sound" is devoted to vacuous interviews with Glennie, who seems positively incapable of saying anything substantial. For example: "My whole life is about sound. It's what makes me tick as a human being." After this daring self-revelation, Glennie ventures into philosophy: "There's sound absolutely everywhere. We have to listen. That's it, really." Having cleared that up, she goes on to win the Ashlee Simpson Award for purest jabber-speak: "We need to eat and we need to sleep and we need music."

The film is a hybrid, combining hard-charging promotion and ponderous meditation. Glennie is seen visiting her childhood home (a last farewell, as it burned down shortly thereafter), working with young deaf children at a British school, giving interviews in her office, traveling the world. "I want to be open to absolutely everything that comes my way," she proclaims (okay, okay, I'll stop). There is a great deal of filler of a fairly predictable kind -- ancient Scottish castles in the mist, cars trying to move in clotted traffic and so on -- and there are lots of artsy camera angles. Nor is most of the music very good; it is, I suppose, some sort of accomplishment to create an impromptu piece with empty plastic bottles and assorted litter on a Broadway street corner, but once the novelty wears off, not much is left.

The best sequence takes place toward the end of Glennie's collaboration with Frith. For much of the time, they've done the usual "free jazz" shtick: crashing, rattling, booming and pulling string bows across items that weren't intended to be bowed -- the musical equivalent of what pediatricians call "parallel play." And then suddenly -- amazingly -- the two artists find a point of agreement: Glennie hammers out a cool, reiterative rippling on her marimba while Frith soars into a gorgeous, lyrical electric guitar solo that is as hymnlike as it is bluesy.

Glennie has long resented any reference to her disability, and she used to speak scathingly of the "plucky little deaf girl" newspaper stories that followed her everywhere she went. In recent years, her hearing has improved, to the point where she now converses easily, with or without lip-reading, and she is able to actually listen to what she is playing, rather than merely feel the vibrations. Her recovery is little short of miraculous, and that human victory is ultimately the best news one takes away from "Touch the Sound."

Touch the Sound (90 minutes, at the Avalon) is not rated but contains nothing offensive.

"Touch the Sound," a documentary on percussionist Evelyn Glennie, is at its best when Glennie plays, but that doesn't happen nearly enough to save it.