By Jonathan Zwickel

ON A RECENT Tuesday night in the Mission District, a stylish, buzzing throng was packed inside Bruno's candlelit Cork Lounge, swaying and snapping to San Francisco's Realistic Orchestra. The 19-piece ensemble were sardined onto the club's tiny stage, pumping enough sound into the narrow room to send ripples through a martini. With the crowd howling like swooning groupies, Realistic swaggered through a big-band rendition of "Jamie's Cryin' ," by composer Anthony Van Halen, then genre-hopped into a smoldering version of Björk's "Venus as a Boy." It was a seemingly odd scenario – morphing FM-radio cock rock and quirky Icelandic pop into a bright, brassy balloon ride – but nothing unfamiliar for the band or their dedicated fans. Heavy metal blowouts, darkened electronica, bouncy hip-hop, a bebop standard or two – it's all in a week's work for the Jazz Mafia.

San Francisco's fickle jazz scene has long been a barometer of its cultural fitness. During the 1940s and '50s, when the Fillmore District swelled with more than a dozen jazz clubs, the city stood as one of the world's great artistic hubs. It rode the wave well into the '60s, when visionary promoter Bill Graham paired young rock bands with jazz heavyweights and kept jazz centered on the city's stage and when the Keystone Korner in North Beach was still alive. Traditional jazz fans shared the music with new audiences during the acid jazz movement of the late '80s and '90s. Players like Peter Apfelbaum, Charlie Hunter, and Joshua Redman emerged, while record labels like Ubiquity and Fog City and venues like Nickie's BBQ and Mr. Five's delivered a revitalized jazz to new crowds. Today, having survived a bout with dubious launch-party "fuzak" during the dot-com boom, intelligent, forward-thinking jazz has taken the city like gangbusters. Or, to put it more accurately, like gangbangers.

Jazz Mafia minions are everywhere, from high-profile midweek club nights to casual, Sunday-morning living-room jam sessions. There's no particular ethnic or ancestral favoritism that links these 20-odd full-time musicians, but rather a passionate dedication to keeping jazz fresh and vital. That means no day jobs, tons of practice, and gigging as much as humanly possible.

"I thought of the Mafia because of the serious respect I saw between all the guys sitting in at our gigs," explains Nick McCarthy, a.k.a. DJ Aspect. "It's all really professional, but it's not competitive." Local rapper Dublin, Jazz Mafia's resident rhymesayer, agrees. "Any cats we saw out at gigs, we just took them into the family."

That's right – a DJ and an MC in a jazz collective. But these guys aren't casually dabbling in coffee shop loungetronica or chanting insipid lyrics over watered-down beats. "It needs to go beyond the novelty thing," says Adam Theis, multitalented trombonist, bassist, composer, arranger, and de facto Mafia ringleader. "As an artist, I want to do more; I want to move forward," he says, noting that the music he's listening to these days incorporates hip-hop and electronica, among other styles. "We're not trying to alienate the audience, but this is exactly the music we want to make."

That attitude launched Theis's music career while he was attending Sonoma State University. Back in 1996 he put together Cannonball, a modern jazz group that gigged in the North Bay for years, playing funked-up renditions of Cannonball Adderly compositions and Theis's elaborate, funky originals. "We played jazz music for regular people, not $50-a-head yuppies, and they responded really well," Theis says. "That band saved my life, I think. I don't know where I'd be right now if it hadn't taken off."

As stimulating as the Sonoma jazz scene was, he decided to move to San Francisco, where he found enthusiastic crowds at North Beach's Black Cat. "They had mostly straight-ahead stuff there then," he says, "and because it was all dot-commers with money to spend, there was a built-in audience. We were allowed to be as weird as we wanted, and so we were: we played really out-there, experimental stuff but with a slamming band. Some of it was awesome; some of it wasn't – but it never went horribly wrong, so they kept it going."

By 2000, at the peak of their popularity, Cannonball's darker, edgier side had swelled enough to spawn a second band, Realistic (not to be confused with the orchestra), that took the "experimental stuff" even further. Realistic grew out of Theis's love of innovative music of all sorts – Squarepusher, Radiohead, Mikah 9 – decimating stylistic boundaries the more jazz-oriented Cannonball merely nudged. "People loved it," he says. "We were getting lots of gigs and big crowds. So Cannonball became a once-a-month thing, and we really started pushing Realistic."

With acid jazz veteran Mark Emenau adding dreamy, cinematic flourishes on vibraphone, drummer Eric Garland looping his own boom-bap rhythms, and Cannonball saxophonist Joe Cohen painting with a digitally enhanced palette, Realistic are hardly a standard dinnertime jazz band. Their misty, atmospheric drum 'n' bass explorations attract ardent audiences as well as curious guest musicians who dig the band's risky, on-the-fly approach. One of those is Dublin, who jumped at the challenge of playing with a seasoned improvisational band. His lyrical sparring with DJ Aspect became such a regular part of the set that another spin-off band was spawned at the end of 2002: Shotgun Wedding Quintet, the hip-hop branch of the Jazz Mafia tree. As the band developed original tunes and instrumentally embellished hip-hop classics, SWQ became the Mafia's most popular incarnation.

Theis's success has something to do with the ongoing, intuitive evolution of styles, which keeps the music fresh. Over the past year he has expanded the horizons two steps further, recruiting a bevy of brass to create the hard-swinging Realistic Orchestra and a six-piece string section – including San Francisco Symphony alums – to form the Shotgun Wedding Hip-Hop Symphony. With five separate incarnations, the Jazz Mafia were a shoo-in for a Tuesday-night residency at Bruno's.

"In my opinion, Adam is a mastermind," Kim Nalley writes via e-mail. Nalley is a nationally acclaimed jazz vocalist who's known Theis since his early days in San Francisco. "He's a bit humble about taking the glory, but really all these projects come about because of him." Nalley, who books Jazz at Pearl's, sees no conflict in supporting local talents like Theis while also bringing in national acts. "Many of the locals are national talent," she flatly states. "When the 'big names' come to Pearl's, they often play with the musicians that live in the area."

Nalley laments the lack of widespread recognition of the gifted locals who keep the city's jazz community strong. "We have an annoying habit of calling this place a 'town,' when it isn't. It's an international city and has been the center of jazz on the West Coast for decades. We started the swing scene, the acid jazz scene, and the techno-electronica jazz thing because not only are we an open-minded city, but we blend and collaborate together. Black, white, Latino; jazz, hip-hop, salsa – musicians all hang together and fuse elements."

Garland, who's been a part of the local jazz contingent since his days studying music at San Francisco State University, says it's "a big thing for any artist, and it's the jazz player's lifeblood. Networking, word of mouth – it's how we get gigs. It's not like we get to see each other around the water cooler at the office." It all comes down to musicians supporting each other, he says. "It's a community that's always been there. 'Jazz Mafia' is just a fun way to think about it."

"There's no reason why we can't foster a flourishing creative environment here in the Bay Area," says Marcus Shelby, the award-winning bassist Theis has unofficially titled "the don of the Jazz Mafia." "We have some of the finest musicians in the world. There are also institutions that genuinely support the jazz scene: Intersection for the Arts, the S.F. Jazz Festival, Jazz at Pearl's, Stanford Jazz Workshop, the Jazz School, and Yoshi's, to name a few."

When asked why many musicians feel the pull of the Big Apple as they consider their careers, Shelby responds, "Artists leave a scene for many reasons: some to find a mentor and places to play; some to study with a particular musician; others to have a fuller artistic experience. I would argue that we have all of these opportunities here in the Bay Area."

His sentiment on the local media mirrors Nalley's. "In the last several years the Bay Area has not made it a priority to expose or critique the jazz scene here. This has been devastating to exposing the scene's creative efforts."

Theis recently celebrated his 30th birthday at Bruno's, with a full house of revelers to give him a hand. A three-band jam session, plenty of toasts, and an all-night musical round-robin established a loose, intimate vibe. The joy and energy in the room was palpable, radiating from the rowdy audience and the crowded stage, as the music moved between Realistic originals like Theis's didgeridoo-driven "Scary" to Dublin's playful cover of Cab Calloway's "Reefer Man." It wasn't until after last call that the room finally cleared out and Shotgun wound down a 40-minute jazz-hop orgy that referenced De La Soul, Too $hort, House of Pain, Kurtis Blow, Digital Underground, and others. The marathon medley could've been dubbed self-indulgent if the crowd hadn't rapped along to every bit.

"We're jazz players with a rock 'n' roll ethic," Garland says. "We want to stick together; we want to write songs together; we want these bands to succeed as bands. We all do our own stuff too, but this is where we really put our time."

Shelby applauds the band's modern, synergistic approach because it's tempered by a devout respect for the architects of the form. "Much like science, technology, or law, precedence largely dictates [jazz's] innovation," he says. "The Jazz Mafia are a shining example of exploring all the historical contexts of jazz while fusing their politics and cultural references through a tapestry of varying styles, from hip-hop to traditional jazz."

With albums by Cannonball and Realistic Orchestra set to release this month on Theis's own 43 Productions label, their popular Tuesday gigs at Bruno's, and myriad side projects, the members of the Jazz Mafia are getting more exposure – and more work – than ever before. As San Francisco begins to take notice, these goodfellas are keeping the family together and the music alive.

Cannonball, Realistic Orchestra, DJ Aspect, and DJ Centipede celebrate the release of Cannonball's From Nightfall to Sun Up and Realistic Orchestra's Live at Bruno's Thurs/17, 9 p.m., Independent, 628 Divisadero, S.F. $10. (415) 771-1421.