The beat is so deep it vibrates in your chest.

It's created by Holly Neal, a registered nurse who pounds a "gathering drum" in time with background music as women surround her playing other percussion instruments - hand drums, shakres, agogo.

No musical knowledge is needed, and no instruction is offered. Each woman contributes her own beat to the group, and participants freely stop to change to a new instrument as the mood strikes.

The women are part of a drum circle that meets at St. Mary's Hope Cancer Resource Center weekly. It's one of several groups that meet in Evansville, and participants say the activity promotes healing, relaxation and group harmony.

Neal, a nurse practitioner and the coordinator of St. Mary's Cancer Center, stumbled into drumming several years ago. She was attending a cancer training session, and a separate drum training session was taking place nearby. Curious, Neal went to see what was going on.

"When I walked into the room and heard it for the first time, I fell in love with it," she said.

In 2003 Neal earned certification in group empowerment drumming from HealthRHYTHMS, a division of drummaker Remo Inc. She then started the drum circle at St. Mary's.

Participation in drum circles produces proven health benefits, Neal said.

Research has shown that group drumming can boost the immune system, she said, and the activity also relieves stress.

During a recent drum circle at St. Mary's, one woman volunteered, "My back has stopped hurting!"

"My neck doesn't hurt any more!" another woman said.

Another recalled bursting into tears as she let go of stress during her first drum circle.

Sue Goff of Evansville, a six-year breast cancer survivor, said she enjoys drumming so much that she sometimes drums on her own at home.

"When I get a little tense or whatever, I go beat on my drum," Goff said.

"You can make any type of beat you want - happy, sad, jazz, blues."

The St. Mary's drum circle is eclectic. Each member is free to play the beat he feels moved to contribute. The Bead Angel on Evansville's West Side and Penny Lane Coffeehouse Downtown also offer eclectic circles. Drumming circles at the Unitarian Universalist Church of Evansville, on Morgan Avenue, also offer what's called shamanic drumming.

In a shamanic drum circle, all the members keep a monotonous drum beat intended to help them reach an altered state of consciousness.

Doug Luzar, co-facilitator of a monthly drum circle at The Bead Angel, said drum circles promote not only healing but also harmony as members blend their sounds to contribute to the group.

"It's the magic of creating in the moment," Luzar said.

"By the time you're done, everybody leaves happy."