ST. PETERSBURG - "Rhythm music" is the label Charlie Hunter gives to his appealing fusion of jazz, acid jazz, funk, blues, rock and occasional bits of world music. He's the chief source of that rhythmic magic, simultaneously playing bass and guitar parts on an eight-string hybrid instrument, and in the process becoming two-thirds of a rhythm section.

His latest partner in time, on Friday night at the State Theater, was Johnny Vidacovich, the remarkable New Orleans drummer best known for his role in long-running Crescent City jazz band Astral Project. The exuberant Vidacovich, as usual, was a show all by himself.

The two, not surprisingly, collided famously, in front of an audience of about 350. Vidacovich's creative, highly interactive approach at times seemed to embody the entire history of jazz drumming. His playing made a perfect match with Hunter's bouncy melodies, sturdy bass grooves and reams of free-flying guitar lines, fattened up, as usual, with an effect that had his instrument sounding like a Leslie-amplified organ.

Josh Roseman, a superb journeyman trombonist associated with Groove Collective, the Roots, Dave Douglas and Steve Coleman, was the very welcome third wheel. He deftly navigated the riff-like melody lines, occasionally using a Harmon mute and/or playing right on top of the microphone for effect. His earthy melody, harmony and solo work nicely complemented that of his bandmates.

The trio, playing without the benefit of regular saxophonist John Ellis (he skipped the gig to vie in the Thelonious Monk International Jazz Competition in Washington, D.C., and landed a second-place finish), mostly stuck to recent concert staples, touching briefly on music from last year's "Songs From the Analog Playground."

Roseman played a high, lonesome, descending line over the rootsy funk of "AC/DC." And the three were joined by members of rambunctious jam band Jacob Fred Jazz Odyssey, for a Latin-tinged take on Nirvana's "Come As You Are," a tune Hunter covered on his 1995 "Bing, Bing, Bing!" album.

Jacob Fred, from Tulsa, Okla., is a band, not a person, with the hyperactive Brian Haas on Fender Rhodes piano, Reed Mathis on electric bass and drummer Matthew Edwards. Mathis often used various foot pedals to make his bass resemble screeching slide guitar and synthesizers, and the classically trained Haas frequently played bass lines with his left hand. The three, playing "Thelonious Monk is My Grandmother" and other whimsically titled originals, turned in a bracing maelstrom of freeform jazz, funk and psychedelia. It made for a riveting journey.