CLARINET VIRTUOSO Richard Stoltzman has been called "an artist of indescribable genius."

"What I am really," he says, "is Peter John's father."

Peter John is 4, and snapshots of him are pasted inside his father's clarinet case. He has a special blazer he wears to concerts, and he has learned to shout "Bravo!" at the end.

"He used to do it when he sat in on rehearsals. I had to tell him, 'Not yet, not yet.'"

For a 4-year-old, Peter John has a lot of miles on him. Just back from a Scandinavian tour, he headed on to Oakland where he lives. School is going to be tough after this.

"His mother Lucy comes with me sometimes," says Stoltzman. "She was associate concertmaster of the San Francisco Symphony for a year. She's the reason I can do all this."

They met at the Marlboro, Vt., music festival, where the rising virtuoso was a fixture for 10 years. His wife recently completed a tour with a Marlboro string group. Sometimes she plays violin with Broadway shows.

Richard Stoltzman makes it all sound so easy. Even with the four hours a day practice. His father, a musical railroad man, used to play clarinet, and little Richard would roll on the floor in delight. Later he got hold of the shiny cylindrical pieces and dangled them out the window like wind chimes. Then he discovered he could make sounds with the thing, jazz sounds, Artie Shaw sounds, and he and his father would do riffs on the hymns at Presbyterian Sunday school.

"I never thought of myself as a musician. I took clarinet in high school: We had an itinerant music teacher who would come by once a week and teach you fingering. My father loved Jerome Kern and Cole Porter and Gershwin, all that great stuff, and I absorbed a lot of that."

He tried Eastman, Juilliard and Marlboro, was rejected, thought about becoming a dentist but got into Yale School of Music and never stopped after that. Today, at 39, with two records, an Avery Fisher Award and an armful of almost hysterically enthusiastic reviews from all over the world, he seems ready to become the James Galway of the clarinet.

Tomorrow he makes his local debut as a recital soloist at Kennedy Center, where he has appeared many times with orchestral groups.

On his recital tours with pianist-composer William Douglas, he endeared himself with his jazz finales, his scat singing and his sneakers. He used to chat with audiences ("Once I announced we would do a rock etude Bill had written, but some old people in the front row got up and left, so after that we called it rhythmic studies"), but this time around both he and the music will be rather more formal.

"That's what they come for, after all," he says. "I don't want to get into gimmicks."

He needn't worry about gimmicks. Just listen to him play sometime. When the rush and bustle of airports and hotels and taxis is finally over and the phones have stopped ringing and the audience is settled down there before him ("I want to say, All right, let's everybody take a big deep breath"), then, at last, he can lose himself in the nirvana of concentration and bring a sound into the world, so subtly you can't be sure when it began, growing in richness and volume, so pure, so lush and palpable you can almost feel it against your cheek.

"You strive for those moments," he muses, "the magic. The challenge in travel is to somehow save something to give the audience, some glimpse. You hope they'll energize you too. There's so much in the world that's not magic. Now, you don't want to be in an ivory tower, you read the papers. But you allow yourself to listen to the grim realities too much, and here you have to play Mozart . . .

"You know, though, sometimes I feel he addresses the human condition more successfully than all the rhetoric. Sometimes I think Mozart is the reality."