A bland buffet of Latin American sounds

The lineup sounded suspiciously tepid to begin with. Artists as disparate as syrupy Puerto Rican crooner Luis Fonsi, visionary Cuban trio Orishas and former Kumbia Kings vocalist Frankie J packaged together by McDonald’s at the Gibson.

No wonder the amphitheater was half empty Friday for the latest edition of Lo McXimo de la Musica. You need a little more star power (or at least a defined aesthetic direction) to fill up a venue of that size.

What’s worse, the festival originally began as a respectable showcase for intriguing Latin alternative artists. This year, marketing considerations must have compelled organizers to put together such an indigestible buffet of incompatible flavors.

Even though the showmanship of headliner Frankie J was impeccable (his timing on the up-tempo numbers betrays the touch of a bona-fide pop star), Orishas was by far the most riveting of the evening’s five acts.

Boosted by additional players on turntables, trumpet and congas/timbales, the Paris-based trio demonstrated once again that it had created some of Latin rap’s most original soundscapes.

“A lo Cubano,” the reckless title track from the group’s seminal debut, sounded as refreshing as it did when it was released in 1999. Songs from last year’s “El Kilo” fared particularly well in a live setting. In fact, that critically maligned record should be reevaluated as a masterpiece of barely restrained funk.

The trio’s sonic recipe is surprisingly simple yet so unique it defies imitation. Their loops are soaked in nostalgic echoes of salsa and Cuban son. And their vocal work contrasts the rapping of MC Yotuel and the nonstop jokes of MC Ruzzo with the singing of Roldan -- an old-fashioned sonero so quintessentially Afro-Caribbean in style that he could make a living crooning sweet boleros if he wanted to.

The set by Nuyorican sister duo Nina Sky provided a sharp contrast to Orishas’ sophisticated sonics. The girls seemed to thrive on the kind of call-and-response choruses and massive synth chords that get your adrenaline pumping if you are, say, 12 years old.

To the organizers’ credit, the evening zoomed by swiftly and without delays. Watching the show, however, left an underlying message that has becoming patently obvious in recent years.

The more Latin music identifies with pasteurized R&B; and radio-friendly hip-hop, the more it loses its earthy sensuality and mystical fervor. Conversely, the more it looks inward for raw, indigenous texture and syncopated rhythm, the more it will find the soul, the purity, the breathless emotion that is so painfully absent from mainstream music these days.