Vijay Iyer Trio, Purcell Room, review The last time I saw pianist Vijay Iyer he was in a tiny jazz club, and was almost close enough to touch. He seemed a real aficionado's musician; the Indian-American intellectual who almost became a scientist, composes pieces for classical ensembles, and crafts improvisations of understated complexity that touch on his Indian heritage as well as jazz. Clearly something has changed. On Wednesday, he and his trio easily filled the Purcell Room, and there was that tremor of excitement that comes when a musician has touched a cultural nerve. He'd barely come on stage before the whoops started. One got the sense of a small cult in the making. It's a fascinating phenomenon, because Iyer is hardly the stuff of cults. Admittedly he has a quietly spoken, heavy-lidded charm, and isn't above pulling the old trick of flattering the audience ("we had to start our tour in London"). But his playing isn't the barn-storming sort that drives Keith Jarrett's audiences wild. And his compositions aren't the sort to set you humming. Many of the numbers in this uninterrupted two-hour set began with a quiet, modest idea, such as two chords in alternation, from which Iyer would tease multiple implications. Giving a sense of big potential lurking in small things is certainly part of Iyer's appeal, allied to a keen sense of form. Different ideas were often cunningly related, and whenever a new idea appeared, the previous one often persisted somewhere down in the bass. This allowed Iyer to create large chain-like forms extending over 20 minutes or more, often building to a tremendous, percussion-soaked climax. Bassist Stephan Crump and drummer Marcus Gilmore were ideally supportive, supplying the textural detail to flesh out Iyer's austere conceptions. Iyer doesn't have the dazzling technical "chops" of a pianist such as Stefano Bollani, and he can even sound awkward at times. The fascinating thing is how he makes this apparent limitation into a virtue. In the number the trio played as an encore, Iyer traced an angular line over a circling bass, in a way that was both gawky and engrossing. Sometimes Iyer was so keen to avoid cliché that he seemed perverse, as in his very strange take on Darn That Dream. And occasionally the deliberate parsimony led to a dour tone. It was when a playful spirit appeared, as in Henry Threadgill's Little Pocket Size Demons, that the evening really took off.