This weekend Grant Park hosts the free Viva! Chicago Latin Music Festival, which features some 20-odd acts, but this three-band Latin-music bill at Ravinia demolishes that whole event. I don’t know of a better contemporary New York salsa group than the one led by trombonist JIMMY BOSCH; on his most recent album, 2004’s El Avion de la Salsa (JRG), he relentlessly stokes the dance floor while still making room for killer improvisation. He likes to call his music “salsa dura” (hard salsa), and he draws from a large arsenal of dance rhythms, including old-school (cha-cha, mambo) and modern (songo) styles as well as Puerto Rican plena and bomba. But Bosch never merely imitates old models, nor does he water down his sound with contemporary electric production. His brassy band plays his tunes with astonishing precision and flair, and though the album includes some distinguished guests–including flutist Dave Valentin, cuatro master Yomo Toro, and pianist Oscar Hernandez–the core group doesn’t need the help. The band’s excellent lead vocalist, Rey Bayona, is a young and stylish singer who’s as comfortable ad-libbing as he is delivering groove-driven melodies.

TIEMPO LIBRE, a group of Cuban expats who’ve worked with the likes of NG La Banda, Cachao, and Arturo Sandoval, made their live debut at Ravinia in 2002, opening for Celia Cruz. Since then the Miami-based ensemble has become America’s leading exponent of timba, Cuba’s R & B-injected variation on son. Its 2004 debut sounded treacly and slick to my ears; its new CD, What You’ve Been Waiting For (Shanachie), is better, though it’s still lousy with chintzy synths, and the group vocals sound more hectoring than propulsive.

Tiempo Libre headlines, Jimmy Bosch plays second, and the Spanish Harlem Orchestra, an excellent ensemble of New York salsa sidemen, opens. Sat 8/26, 7:30 PM, Pavilion, Ravinia Festival, Green Bay & Lake Cook Rds., Highland Park, 847-266-5100, $30, $15 lawn. All ages.