Peering out at his fans from beneath his dapper black felt derby, Yomo Toro explained how he wrote "Funky Jibaro": "I put the melody from Puerto Rico with a beat from here."

This is certainly not a new formula. But that made no difference last night to Baird Auditorium's front-row occupants who, during a prolonged and heated salsa tune, shouted and sang "Viva Puerto Rico!" in multi-part harmony.

Like a number of Latin American folk musicians, cuatro player Yomo Toro has embraced his share of the pop influence. One might say that the group's high decibel levels merely reflect what has happened to the cuatro, which has evolved from a four-string guitar to a 10-string, metal-strung powerhouse. But still, Toro's folk roots are always present: in the syncopated rhythms of "Seis Chorreao," borrowed from Puerto Rico's mountain folk, and in the rhapsodic, flamenco-style melodic whirls of "Little Black Angels."

Positioned alongside an international crew of backup musicians, Toro played ebullient Buddha, catalyzing the action onstage and in the house while remaining motionless. Only his fingers were busy -- spinning out astonishingly fast riffs, coaxing vocal-style vibrato from his cuatro's sympathetic strings and rapping his instrument in biting style.

Because no fewer than four percussionists played at once (a sound linked to Puerto Rico's African heritage), there was no apparent reason to press the sound envelope. Still, Yomo Toro overamplified. The speakers, combined with some harsh miking, nearly destroyed the program's first half. Baird Auditorium, ideal for intimate evenings with string quartets or sitarists, cannot handle all the sound the Conjunto pumped into it. After intermission, though, things quieted down a bit, and audiences could enjoy the soft edges on Luis Kahn's violin solos and singer Dalia Silva's belting vocal numbers.