The musician and writer David Grubbs began his career far from the silence and mushrooms of John Cage, the musician, philosopher, and writer. As a teen-ager in Louisville, Grubbs formed the band Squirrel Bait, an organized explosion that converted punk rock into something twice its original size, more melodic and chaotic than earlier iterations. From there, Grubbs moved into a series of disparate bands, mostly playing music fairly far removed from the tendencies of rock. One long-running project that he conducted with Jim O’Rourke, Gastr del Sol, seemed like a collation of all the parts of sound that are deëmphasized on mainstream rock records: silence, dissonance, scrapes, and squeaks. THE NEW YORKER