Club Acts.

I had a curious experience in downtown Manhattan the other night. Early in the evening, I attended a concert of works for instruments and electronics by Alexandra Gardner, at the Greenwich House Music School, on Barrow Street. Then I went to the East Village to catch a late show by the clarinettist and composer Evan Ziporyn, at a club called the Stone. Arriving on Avenue C with a few minutes to spare, I stopped in at a corner deli, and, as I browsed for chips, I was amazed to hear the beautifully fractured finale of Gyorgy Ligeti's Violin Concerto on the P.A.--a New York Philharmonic broadcast, with Christian Tetzlaff playing and Alan Gilbert conducting. I felt as if I had stepped into an alternate universe where New York evenings unfolded to a contemporary-classical soundtrack.

We're not at the point where Stockhausen's "Gruppen" rumbles over the loudspeakers at Starbucks and American Apparel, but there's more new music in the city than ever before. Forty years ago, New York had just two full-time new-music ensembles: the Contemporary Chamber Ensemble and the Group for Contemporary Music. Now there are more than forty such outfits, from Alarm Will Sound to Wet Ink. Although these groups sometimes play in the uptown concert halls, they more often appear downtown and in Brooklyn. The Stone features experimental composition alongside free jazz and non-commercial rock. So does Tonic, which, sadly, has been priced out of the Lower East Side and will close its doors on April 13th. And, on a recent night at the Williamsburg art space Galapagos, the ensemble ThingNY played a sometimes punishingly loud set of pieces for electric guitar, trombone, keyboards, bass, and drums, while, in an adjacent room, R. Luke DuBois mesmerized a hipster bar crowd with organically shifting masses of electronic tone. The latter event was part of a monthly series called Darmstadt, named for the legendary avant-garde gathering where Ligeti made his reputation.

An exceptionally vital group of young composers is driving the proliferation of new music. As they pontificate on blogs and Web sites such as Sequenza21 and NewMusicBox, distribute music via MySpace pages and Internet radio, and post flyers for their shows, they act for all the world like unsigned rockers trying to make it in the city. Some, like Christopher Tignor, have adopted a double identity, studying composition by day (in Tignor's case, at Princeton) and playing by night in a post-rock band (Slow Six). Classifying their work becomes tricky; many composers of Tignor's generation are erasing the line between classical and pop, dispensing with performers in favor of laptops, incorporating improvisation and world-music practices, or singing their own art songs in semi-pop style. Complicating the picture further is a new breed of pop artist who composes on the side. Glenn Kotche, the drummer of Wilco, has released an album of solo works on Nonesuch; Franz Nicolay, the keyboardist of the Hold Steady, also writes for the rock-inflected Antisocial Music collective. The long-reigning master of genre ambiguity is John Zorn, who founded the Stone in 2005, and whose madcap career has unfolded at the intersection of popular culture and jazz, rock, and classical composition--otherwise known as the corner of Second and C.

Sometimes the blurring of boundaries leads to overamplified mush. Just as often, though, it generates a new kind of interstitial music--one that makes a virtue of falling between the cracks. In Nico Muhly's "Keep in Touch," the weighty, gospel-tinged voice of the singer-songwriter Antony Hegarty is interwoven with broken scales on the viola and bubbling electronic textures. In Gardner's "Luminoso," flamenco strummings are digitally processed in a way that evokes a lone guitarist wandering around a sun-baked ruin. And at the end of Ziporyn's set at the Stone a quartet of players--the composer on clarinets, Robert Black on bass, Ha Yang Kim on cello, Nathan Davis on percussion--improvised on notated parts to create a work of disciplined wildness that will never be heard in exactly the same way again.

Since George Gershwin's time, people have been ...