Synthesizer innovator Robert A. Moog dies:The Beatles used a Moog synthesizer on their 1969 album "Abbey Road"; a Moog was used to create an eerie sound on the soundtrack to the 1971 film "A Clockwork Orange."A childhood interest in the theremin, one of the first electronic musical instruments, would lead Moog -- whose name rhymes with vogue -- to create a business that tied his name as tightly to synthesizers as the name Les Paul is to electric guitars.As a Ph.D. student in engineering physics at Cornell University, Moog developed his first voltage-controlled synthesizer modules with composer Herb Deutsch. By the end of the year, R.A. Moog Co. marketed the first commercial modular synthesizer."Suddenly, there was a whole group of people in the world looking for a new sound in music, and it picked up very quickly," said Deutsch, a Hofstra University emeritus music professor. "The Moog came at the right time."As extended keyboard solos in rock and funk -- and later hip-hop and techno -- took off, Moog\'s instrument was used in songs by Manfred Mann, Yes and Pink Floyd."The sound defined progressive music as we know it," said Keith Emerson, keyboardist for the rock band Emerson, Lake and Palmer.