Their name seems to promise mandolins as far as the ear can hear–and if that were what they actually delivered, it’d be reason enough to ignore them entirely. But the JMP features only a single mandolinist, Jamie Masefield, and he doubles on banjo in what’s really a variation on the tried-and-true power trio. More important, in both his own playing and his group concept, Masefield shakes off the stereotypes that cling to the mandolin, from the bluegrass-inspired “dawg music” of David Grisman’s bands to the Sicilian sobriety of the theme from The Godfather. He can tap those idioms if the music demands, but on the recent Tour de Flux (Accurate), the trio’s second album, Masefield devotes most of his energy to making his primary instrument at home in the jazz mainstream–no small task, considering he’s working with a paired-string lute that predates jazz by a few centuries. It has little natural volume or sustain, and amplification and electric manipulation, which work so well for the guitar, dilute the mandolin’s distinctive timbre. Others tend to combat this problem either by trilling each note to keep it ringing–a surefire way to stop a jazz solo in its tracks–or by using the evenly accented melody lines found in the earliest jazz, as well as in bluegrass, to camouflage the notes’ rapid decay (if you keep ’em coming, people won’t be able to hear how fast they disappear). But Masefield, who clearly listens to as many horn players as fret men, instead embraces the mild syncopations that give current mainstream jazz its virile bounce; he relies on a tasteful amount of amplification and the support of his rhythm mates to make it work. The latest album benefited from the agile antics and reliable beat of drummer Jon Fishman of Phish, but on tour a newcomer named Ariel Hoenig springs the traps. The heart of the group’s present sound is upright bassist Chris Dahlgren, who led his band Slow Commotion into Chicago in 1996; the JMP had an electric bass when it started up six years ago, but it’s already hard to imagine the band without Dahlgren’s dry tone and strong, graceful foundations. Thursday, April 22, 10 PM, Schubas, 3159 N. Southport; 773-525-2508. NEIL TESSER

Art accompanying story in printed newspaper (not available in this archive): uncredited photo.