The synthesizer pioneer died of a brain tumor. “At the height of his synthesizer’s popularity, when progressive rock bands like Yes, Tangerine Dream, Kraftwerk, and Emerson, Lake and Palmer built their sounds around the assertive, bouncy, exotically wheezy and occasionally explosive timbres of Mr. Moog’s instruments, his name (which rhymes with vogue) became so closely associated with electronic sound that it was often used generically, if incorrectly, to describe synthesizers of all kinds.”