Robert A. Moog, creator of a musical synthesizer that turns electric currents into sound, has died at the age of 71 in Asheville, NC (USA). As a Ph.D. student in engineering physics at Cornell University, Moog developed his first voltage-controlled synthesizer module in 1964, enabling musicians to generate sounds that could mimic nature or seem otherworldly. "The sound defined progressive music as we know it," said Keith Emerson, keyboardist for Emerson, Lake and Palmer.