Several minutes into her matinee performance at Carnegie Hall's beautiful new basement theater, as part of the When Morty Met John festival, pianist Margaret Leng Tan stopped and, without a microphone, addressed the audience.

"A little Cage in the house," she said.

She had little choice but to acknowledge the racket in the room. Disembodied voices and a radio playing pop music were clearly audible. Later, loud rumblings and a strange bit of static made their way through the air, seeming to come from another part of the building via the p.a. The noise persisted throughout the hour-long recital without correction, as if management had simply told Leng Tan she could use the room for the afternoon but they were going to be busy. The house lights never even came down.

Despite the intrusions (if barely), the majesty of Cage's masterwork showed through. Sonatas and Interludes is generally recognized as the invention of the prepared piano, and at a time when manipulating the inside of the instrument has become almost commonplace, there's something graceful about seeing the piece performed. Cage wrote it when he was primarily working with percussion ensembles, and the piece is composed in a similar fashion, which is to say that (unlike the work of many contemporary augmenters) the preparations don't change over the course of the work. As opposed to the steady altering of mutes and blocks against the strings in improvised settings, Sonatas and Interludes builds a recognizable set of voices across the keyboard. It becomes a language much like, as has been observed before, a gamelon. The player remains seated (no busy moving of pie tins and gaffer's tape), playing in a traditional concertstyle. But the sounds the instrument emits, with its strings plugged with erasers, washers and weather stripping, are unexpectedly, beautifully alien. It's a light but very composed piece with logical progressions and well-conceived variations.

Near the end of the performance, the rogue voices became clearer - "The house ... could you bring reverb into this?" - and the final piece coincided almost magically with some phantom electric guitar riffs. It's a good thing Leng Tan wasn't playing a Morton Feldman. Cage, at least, would have grinned.