Ponty and Anderson bring enthusiasm, sparkle to a prog night at Keswick

At 71 and 73 respectively, vocalist Jon Anderson and violinist Jean-Luc Ponty have already lived long lives in the prog-rock biz as respected solo artists, holding storied jobs for acts such as Yes (Anderson), Frank Zappa, and Mahavishnu Orchestra (the last two, Ponty). Why not join forces, then, for something progressive and ethereal, the AndersonPonty Band, a 2015 album (Better Late than Never) and a tour that hit the Keswick Theatre Tuesday night?

Philadelphia, long a stronghold for Ponty and Yes, welcomed APB with cheer. Whether the offerings were new tracks penned by the bandleaders (the gentle arpeggios and hammy metal riffs of "One in the Rhythm of Hope"), highlights of each man's solo career (Ponty's Zappa-like "Enigmatic Ocean" was particularly rousing), or old Yes classics reassembled, the crowd was up for it.

That enthusiasm was largely a response to the interplay between the veteran experimentalists. In newer songs such as the lushly aquatic ballad "Listening with Me," Ponty played with a rounded, brassy sound while Anderson hit on a vocal style that was more ragga than his usual mystical rock-elf tone. Quite simply, they clicked, and you could tell.

There was a question of how Anderson would sound. The late Yes bassist Chris Squire (who got a name-check before a gorgeously elegiac version of "And You and I") wouldn't allow the singer back into the band due to vocal problems. But on Tuesday night, Anderson was magnificently strong and in command of all his hearty highs. Sometimes that meant wordlessly scatting to a lengthy Ponty solo (think Airto and Flora Purim). At other times, Anderson let loose with powerful vocal sunbursts, as on "State of Independence," a towering, fast track written with Vangelis that just seemed to grow larger with each note.

During the second set, Anderson found delight in jiving to the ensemble's quieter, odder moments, such as the happy chase-the-blues-away country of "Never Ever." Doubly haunting was how Anderson and company broke down epic Yes tunes such as "Wondrous Stories" and "Long Distance Runaround," respectively, into cocktail jazz and twinkly gypsy tango. The former song cast Anderson in a blue mood and weary tone reminiscent of Little Jimmy Scott, while the latter gave singer and violinist a chance to run down a halting Argentinian cabaret vibe that would have made Astor Piazzolla proud.