A 16-year old boy sits hammering a drum at Camp Karl Holton, a Los Angeles County juvenile probation facility in San Fernando. He swings a mallet first with his left hand, then with his right, then furiously with both.

He is thinking about his brother and sister, killed three years ago in a gang-related shooting. The tip of one mallet goes flying. A blister the size of a dime forms in the fold of his left hand.

Sitting at the far end of the circle is Mario, 18. He strikes the drum with less force. Most of his anger, he says, is gone. The scar on his left check was left by a bullet, but he says he’s through with the streets. He’s going home soon. This time, he says, he’s not coming back.

The anger and regret of 11 boys with drums sound like thunder and look like battle. The drumming diminishes gradually, and when it ends, there are exhausted smiles, heaving chests. Silence.

“Good,” says Steven Angel.

Angel, 46, is founder of Drumming for Your Life, a musical approach to the health and healing of mind, body and spirit based in Santa Monica. A child prodigy, who performed at age 6 with the legendary Buddy Rich looking on, Angel spent most of his life on the fringe of stardom.

Two years ago, he started the drum therapy program, which has been used by cancer patients, yoga students, men’s groups, high school students—anyone harboring emotions trying to emerge.

For the boys at Camp Holton, it is a chance to express feelings that words alone cannot. Incorporated into the music program by volunteer instructor Fletcher Beasley, drum therapy serves as a vent and as a bond.

“There’s a lot of anger, resignation to the way things are in the world,” Beasley says. “There’s a lot of sadness and fear. A lot of that is lifted from them by this program.”

Mario says he feels good at the end of the one-hour session, although he isn’t sure exactly what it is about the drums that makes him feel that way.

“You get everything out,” he says. “You let out some stuff you don’t even think about. It’s weird.”