Notable makers of all-in-one analog synthesizers included Moog, ARP, Roland, Korg and Yamaha. Because of the complexity of generating even a single note using analog synthesis, most synthesizers remained monophonic. Polyphonic analog synthesizers featured limited polyphony, typically supporting four voices. Oberheim was a notable manufacturer of analog polyphonic synthesizers. The Polymoog was an attempt to create a truly polyphonic analog synthesizer, with sound generation circuitry for every key on the keyboard. However, its architecture resembled an electronic organ more than a traditional analog synthesizer, and the Polymoog was not widely imitated.