"This is the real deal," irrepressible singer Al Jarreau, still a master of impressively athletic vocal contortion, promised at the start of the West Central Florida stop of Montreux Festival on Tour. "There's no sampling, and no prerecorded music," he said Monday night, in front of a 2,027-strong crowd at the Tampa Bay Performing Arts Center's Carol Morsani Hall. Jarreau, constantly in motion while onstage, expressed that sentiment several times throughout the enthusiastically received 2½-hour show. And it was a pledge that was partly fulfilled, despite the presence of a couple of banks of synthesizers and several tunes so rhythmically rigid that they might as well have been pre-recorded.

The concert, unlike other smooth-jazz events, seemed less tightly programmed, offering more opportunities for spontaneous interaction among the five co-headliners and seven or so supporting performers. The show began with a bang, as Jarreau, vocalist-pianist Roberta Flack, alto saxophonist David Sanborn (a Tampa native), pianist Joe Sample and George Duke, keyboardist, singer and musical director for the tour, joined forces for a vibrant soul throwdown.

The proceedings turned into an uneven mix-and-match affair, starting with a short segment featuring Crusaders founder Sample. He turned in a pleasantly redesigned version of "Street Life," beefed up with the inspired gospel/R&B work of three back-up singers. Duke and Sanborn then reappeared for the funk-punched "Camel Island," a showcase for the latter's playing, as ultra-bright and shiny as ever. The saxophonist knows his way around the horn, but his much-imitated style makes no accommodations for subtleties. Duke subsequently took center stage, cranking out some spacey sounds before offering snippets of material from his forthcoming "Cool" album, including a Stevie Wonder-ish ballad. The rotund keyboardist seemed determined to revisit all stages of his diverse musical education. He tossed off a classical ditty, grooved on the soul-jazz of "Mercy, Mercy, Mercy," from the repertoire of his old employer Cannonball Adderley, and played truncated versions of "On the Wings of Love," the 1982 hit he produced for Jeffrey Osborne, and "Sweet Baby," his successful 1981 single with Stanley Clarke.

Flack, now based in Miami, traded verses with Jarreau on a convincing interpretation of the chestnut "All the Way," and revisited mid-'70s hits "Feel Like Makin' Love" and "Killing Me Softly With His Song" (but not "Where is the Love"). She also dipped into 1995's "Roberta" CD, for a gospel rave-up reinvention of "Sweet Georgia Brown."

Jarreau, gung ho to a fault, electrified the crowd with a typically over-the-top gallop through "Mornin'," the cheery 1983 single he described as the song that "got me on the radio during the day." Instead of delivering other favorites from the same era, he engaged in an extended work-out on the title track from his recent "Tomorrow Today" album, finally wandering into an exuberant, earthy Latin jam, bolstered by the stand-out conga work of journeyman percussionist Lenny Castro. Jarreau, always a joyful and entertaining presence, nevertheless was responsible for two of the evening's most commercial and least appealing moments, when he asked the audience to sing the title of his new disc and, later, the model of a new car from the auto manufacturer sponsoring the tour. No, thanks.