(Jahi Chikwendiu/The Washington Post )

The noise of the drums is a low, deep rumble, like the sound of an approaching train. It begins just outside the Gothic bronze doors of Washington National Cathedral and grows — and grows — as a crowd of hundreds files into the church. Each person takes a seat in the concentric circles of chairs that fill the long nave, pounding on the drums they hold between their legs or banging on their tambourines. Now, the noise is deafening.

Katy Gaughan stands at the center of a circle of djembes, the goblet drums of West Africa, and counts down for silence. Three, two, one — and the pulsating clamor ceases.

“We have been invited into this holy space,” Gaughan says to the crowd of more than 700, young and old, dreadlocked and dressed-for-work, some carrying handmade wooden flutes, others sitting primly with triangles or tambourines. “I invite you to drum your prayers.”

A drum circle inside a cathedral feels a bit like a witches’ coven at a baptism or a tie-dyed shirt at a state dinner. Yet on this cold winter night, it hardly matters. It’s hard to worry about propriety when you’re focused on matching the dum-dum-dum-dum, dum-dum-dum-dum reverberating all around you.

Forget the Deadheads and Occupy Wall Street protests. The drum circle has gone mainstream.

These days, you’re as likely to find a drum circle at a Delta Air Lines team-building workshop, in a prison or at an elementary school as at a hippie gathering. Drum circles are featured at weddings and funerals, or they’re used to help seniors with dementia. In the Florida Gulf Coast community of Nokomis, retirees sit on the beach in folding chairs, sipping cold drinks as they watch the sun set to the rhythmic beat of drums. Even Kate Middleton has gotten into the act; Britain’s Duchess of Cambridge joined a drum circle at a children’s mental health facility in December.

Washington is home to possibly the oldest and longest-running drum circle in modern times, the one that gathers every Sunday at Meridian Hill Park. Formed in 1965 in reaction to the assassination of Malcolm X, it has met for more than 50 years.

That circle is a free-form community event with no leader, the rhythm dictated by the group’s mood. But many drum circles, which are based on the native and aboriginal traditions of West Africans and Native Americans, are led by a facilitator. Yes, that’s a career choice.

Members of the Abenaki tribe perform a drum circle in Vermont in May 2012. Drum circles are based on West African and Native American traditions. (Damian Dovarganes/Associated Press)

The guru of drum-circle facilitators is 69-year-old Arthur Hull, who started the first facilitators’ workshop in Hawaii in 2000 and has since taught, by his count, at least 10,000 people worldwide how to lead “rhythm-based events.”

His goal, says Hull in a phone interview from his base in Santa Cruz, Calif., is to “get to the point where people realize it’s not just about drum-circle facilitation. You can facilitate community.” His facilitators “end up being elders in the communities that they helped build.”

One of his protégés is Jonathan Murray, founder of FunDrum Rhythm Circles, based in Columbia, Md. Murray says his drum circles offer a cornucopia of benefits for the workplace: team building, diversity training, morale building, stress relief, employee burnout intervention, and celebrations to recognize achievement. He has led circles for Delta Air Lines, Beam Suntory and Johnson & Johnson. He also offers drumming wellness programs that purport to boost the body’s immune system, as well as community programs to help build children’s confidence or revitalize a church community.

Murray’s latest project is working with Maryland social workers on stress relief and team building. Social workers are “really on the front lines,” he says. “They’re exposed to so much trauma.” The drum circles offer them “very powerful outcomes.”

Laurie Precht, 52, facilitates another of the Washington area’s longest-running drum circles. Carroll Rhythms, based in Westminster, Md., has been meeting monthly for 15 years. Precht, who is also a school library media specialist, also runs a weekly drum circle with the children at her Baltimore County elementary school for autistic children.

Nellie Hill, 66, co-author with Arthur Hull of the “Drum Circle Facilitators’ Handbook,” runs Playful Spirit Adventures, which organizes monthly community drum circles in Ellicott City, Md., as well as circles for schools, home-schooling groups and ­special-needs children.

“It used to be that drum circles were people getting together and just banging at drums,” she says. Now she thinks people better understand the benefits, “not only for team building, but for health and wellness, for helping people get back into society. There are a lot of different purposes.”

On a sunny morning at the Old Capitol Pump House on the Anacostia River near Nationals Park — today the home of Earth Conservation Corps — a circle of sleepy-eyed young men and women slouch behind their djembes.

“You don’t need to know anything,” leader Jim Donovan, the author of “Drum Circle Leadership,” tells them. “If you feel you messed up, just smile and keep going.”

Within seconds, the circle is following an increasingly complex drumming pattern. “Don’t think, just drum,” Donovan coaches.

Many of the participants are employees of Access Green, an energy efficiency contractor whose chief executive, Joe Andronaco, discovered drum circles when he was in recovery for drug and alcohol abuse. His workers, Andronaco says, often come from tough backgrounds, marked by single-parent homes, incarceration and substance abuse.

A drum circle “is a way to address trauma and provide coping skills,” he says. “We’re trying to rewire the brain waves to say, ‘You’re not a horrible person, you’re not supposed to be on this negative side of life. You can engage in a positive way.’ ”

As the sun streams into the old pump house, the drummers relax, looking at each other and smiling. “What we just experienced is an example of what we will be doing through the day — using music and sound as a transformative force,” Donovan says. “Going from ‘My mind is going a million miles an hour’ to ‘I’m fully present.’ ”

Back at the cathedral, the joint is jumping. It feels like a cross between a religious revival and a rally for Democratic presidential candidate Bernie Sanders. (Yes, there have been Sanders-themed drum circles.)

It’s so loud that bright orange earplugs are handed out, and, even then, the beat still permeates. People are dancing in the aisles.

In the center, alongside facilitator Gaughan, is drummer Kristen Arant, known as the Drum Lady. Her powerful arms work a djembe as she dances, keeping the beat moving.

Arant runs a group called Drumming Up from Poverty, which aims to improve the lives of street children in Ghana, as well as the Washington-based Young Women’s Drumming Empowerment Project, which encourages self-esteem and “creative self-expression.”

She sees drum circles drawing people from all backgrounds. In a circle, “there is one language happening, and that is rhythm,” she says. “In this extremely divisive time, there is humanity in the world.”

After the drumming finally comes to an end, Gaughan reflects on the event.

“I think people are hungry for connection, for something they can do,” she says. “It really blew me away.” When 700 people show up, “that’s what people are hungering for.”

Plus, it’s just plain fun.