Anthony Pirog led a 22-member ensemble through a free performance of Terry Riley’s “In C” as part of the annual Sonic Circuits Festival of Experimental Music. (All photos by Marlon Correa/TWP)

With its steady cadence, shifting patterns, staccato notes and shimmering effects, the 55-minute rendition suggested such Steve Reich pieces as “Music for 18 Musicians.” This was not especially surprising, since Reich subsequently developed the principles of “In C” more than Riley did. And it was Reich, as a member of the ensemble for the composition’s 1964 premiere, who suggested that it needed an unwavering pulse — provided on Saturday by Kenny Pirog’s cowbell. This seems to reflect Reich’s interest in Balinese gamelan more than Riley’s principal influences, which include jazz, Indian classical music and John Cage, whose compositions often rely on chance.