As conductor Carlos Kalmar noted at the beginning of Friday's Grant Park Orchestra series finale, there is a history of classical composers adopting traditional folk themes into their compositions. Friday evening's performance emphasized folk melodies from Latin America, and paired the Grant Park Orchestra with popular Peruvian folk sextet Inca Son.

The orchestra opened with a stirring performance of Argentinian composer Alberto Ginastera's "Dances from Estancia Opus 8A," which wove together four traditional dance tunes. In this piece and later collaborations with Inca Son, Kalmar and the orchestra showed a flair for capturing the passion of the sensual pieces without the stiffness all too often a characteristic of collaborations between orchestras and popular performers.

Next, the orchestra was joined by the six members of Inca Son. This Boston-based ensemble, led by composer/vocalist Cesar Villalobos, has been instrumental in introducing Peruvian music to North American audiences and to a new generation of Peruvians, who have embraced them as cultural heroes.

The band members were a sartorial sensation in bright red costumes, iridescent blue and gold capes, and feathered headdresses. All six players are multi-instrumentalists and switched freely between wind, percussion and stringed instruments. Peruvian music is airy, thanks to the variety of flutes and pipes of pan, but also grounded with a driving, percussive beat contributed by drums and vigorously strummed fretted instruments.

Inca Son began "Mi Cambio" as a pastoral meditation blending flutes with Ellen Mastenbrook's soulful violin. The orchestra joined in slowly, with the string section amplifying on the theme presented by the violin, followed by the wind instruments embellishing the flute motif building up to a big finish.

Without the orchestra, Inca Son performed several numbers including a vibrant adaptation of the most familiar Andean melody, Daniel Alomias Robles' "El Condor Pasa," which Villalobos characterized as "the hymn of the Andes." On this and several other numbers, Villalobos punctuated the melody with loud blasts from a long Andean horn made out of a bovine horn grafted onto a wooden tube.

For the second half of the program, Inca Son was joined by their four dancers, whose colorful costumes, playful stage presence and athletic technique made them crowd favorites. Villalobos also sang one of his most popular numbers, "El Abuelito," which he wrote about his grandfather, who lived to the age of 113.

Villalobos and company finished by venturing close to rock 'n' roll with a distinctly Peruvian spin on "La Bamba."