Batala Washington, an all-female Afro-Brazilian band that plays samba and reggae rhythms, rehearses at the Lab School. (Astrid Riecken/For The Washington Post)

You hear them long before you see them: Big, booming sounds bouncing off buildings that grow more insistent and precise in their polyrhythms as they approach. And when the musicians come into focus, swaggering and moving with the beat, there is another surprise: They are all women.

Batalá Washington, 80 women strong, has been delighting audiences for a decade, bringing the Carnival rhythms of the Bahia region of northeast Brazil to the District and beyond, even as they show a force of solid sisterhood.

They are young, old, black, white, petite, large, tall, short — all working this indomitable, percussive cultural-delivery machine.

Although they are part of an international movement that began in France 20 years ago, Batalá Washington maintains its unique status, says Alison Rodden, the group’s musical director.

“There are over 35 Batalás around the world and here in the U.S. there’s about to be 10,” Rodden says. “We were the first one that was 100 percent women.”

A fixture at city marathons and street fairs, Batalá has played internationally, led both big Women’s Marches in the District and opened for the Rolling Stones in 2012.

“How many people can say, ‘I opened for the Rolling Stones?’ ” says Carol Freitas, one of a handful of Brazilians in Batalá.

“We played with Sheila E., we played with Wyclef Jean,” Rodden says. “And then of course, in Brazil, we performed with a lot of the founders of the genre samba-reggae. Even the Blue Man Group asked one year if we could play with them.”

There is a growing demand for them to play in town, with up to 10 performances a month come summertime.

As much as they’ve accomplished in a decade, Rodden says, “it’s just a beginning for us. We’re taking the band to a new level. Some of our members have been in the band nine or 10 years now, so it’s important for those who are technically advanced and been around a bit, but we’ve also got people who started yesterday.”

The band rehearses every Saturday and performs throughout the Washington-Maryland-Virginia metropolitan area. (Astrid Riecken/For The Washington Post)

Most newcomers are trained on the largest drum — the surdo — big as a Western bass drum and played with mallets — which provides the heartbeat of the sound. The nearly-as-big dobra offers a melody that plays in call-and-response style with the tom-tom-like repique, while the snare-like caixa offers the highest-pitched clatter.

“There’s something pretty incredible about having all women with these drums strapped around their waist,” says Janine Sayles. “It’s very empowering. And I think that we empower a lot of women who watch us.”

After all, few women were encouraged to take up the drums, Rodden says. When it came time in elementary school to choose instruments, she says, “they’re like, ‘What do you want to play?’ For girls, it’s flute or clarinet.”

Even now, the ranks of professional female drummers is fairly limited.

So when a big unit of female drummers marches noisily toward you, “it’s undeniable,” Rodden says.

For some band members, Batalá is a chance to pick up on drumming they otherwise had to give up with college marching bands.

“I’ve drummed all my life,” says Ellen Arnold-Losey, a member since 2010 who is originally from Iowa. “Once you finish school, there’s not many opportunities to play anymore.

“I did a summer with a professional drum-and-bugle choir. I tried these hand-drumming circles. I tried drum set,” Arnold-Losey says. “They weren’t a good fit for me. And then shortly after I moved to D.C., I happened upon the band, and I was like: That’s the thing I was looking for.”

There was a learning curve, she says. “My background was American, traditional, Revolutionary style of drum-line drumming, and this is Brazilian. It’s got a very different swing. The rhythms move in ways that are different than I was used to before,” Arnold-Losey says.

Most of the learning is done in the rehearsals. One recent Saturday, in the empty morning-after of a U Street disco, Rodden faces the eager drummers with a variety of hand signals and encouragements.

“Don’t be shy about anything,” she says to newcomers about their demonstrative movements. “If you think something is too much, take it two steps beyond.”

There is no sheet music, video training or reference materials. “That’s consistent with the tradition of how the music was taught in Brazil,” says Rosa Moreno.

“The oral tradition of teaching and learning is really critical. That’s something we really embody with the music, and it also helps create community,” Rodden says.

Each Saturday without fail, they gather to rehearse for four hours, perfecting their approach on their array of colorful drums, sometimes capped by a guerrilla street performance.

“There’s something pretty incredible about having all women with these drums strapped around their waist,” Janine Sayles says. “It’s very empowering. And I think that we empower a lot of women who watch us.” (Astrid Riecken/For The Washington Post)

There’s more women who have wanted to join Batalá than there are drums to give them, so often months go by without accepting new members.

A visitor to Saturday practice is first offered earplugs. Loud enough at their regular audition spot at Hancock Park near the L’Enfant Plaza Metro station, they are even more necessary in the indoor spaces at the 9:30 Club or nearby Town Danceboutique.

“We used to rehearse at Farragut Square, but we got kicked out because a hotel there complained of noise,” Freitas says. “Then we had rehearsed at Dupont Circle, got kicked out.”

“You name it and we’ve been kicked out of there,” Rodden says.

Rehearsal spaces now seem stable, especially because the federal offices near Hancock Park are otherwise deserted on Saturday mornings.

There, one of the newest drummers is Emily Smith, 37, an “aspiring” band member who, after a number of rehearsals over time, can become eligible for her own drum. The Louisiana native, a program manager at the National Oceanic and Atmospheric Administration, had a decade of drumming experience.

“But this is brand new,” Smith says. “The dancing, for one thing, and all the choreography. I did a marching band, but that’s a very different thing.”

So far, she says, “it’s a really good vibe. All the women are very welcoming. We remind each other we’re here because we love this. There doesn’t seem to be any tension among us because we all love this. Nobody’s getting paid. But I love seeing we’ve had women in their 70s down to their 20s.”

“That’s one of my favorite things about this band,” says Ashley Elstro, 30, a data analyst in the senior living industry. “I feel like I’m learning so much about ladies of all ages, all walks of life, all different professions, so if I ever have an issue, there’s always somebody I can learn from.”

The oldest current member of Batalá is Charlotte Conley, 66, a reading teacher in Congress Heights. She decided to join “a couple months before my 65th birthday. It was my birthday present to myself.”

“My friends and family were shocked,” Conley says. “I had no musical genes whatsoever. But apparently I can rally some rhythm.”

She had seen Batalá at a street festival in 2014. “Everybody was dancing and having a great time. And it was also a strong group of women. You could feel the energy and the camaraderie.”

The group was very accommodating to her, Conley says. “I got hip replacement surgery January last year, but it hasn’t made a bit of difference. I played sitting down for a while. They’re very accommodating to my using adaptive equipment. Half of the rehearsal I play standing up at the drum, and half I play with my drum stand.”

“I don’t think I would have done it had it been a co-ed group, considering I have no musical ability whatsoever,” Conley says. “The fact that it was an all-female group felt much more supportive and accepting. And they were very accepting.”

Compared with her friends who also settled in the District after college, Cait Nordehn says she has found a wider community surrounding her, “built over the past five years, where I’ve met people from all over the DMV that I probably wouldn’t have met who are older, younger, from different places and different professions. This is what’s been really enriching just as much as the music.”

Would it be different if men were in the group?

“We talk about it sometimes,” says Nordehn, who plays the speedy sixteenth notes on the caixa: “What if we invited men to join us? While I would certainly welcome that, I think there’s a special relationship we have and a different way we can be just among women.”

Having only women, says Karon Phillips, brings a “certain level of deeper understanding among each other without it even being said.”