The Yamaha DX7 is an FM synthesis based digital synthesizer manufactured by the Yamaha Corporation from 1983 to 1989. It was the first commercially successful digital synthesizer. Its distinctive sound can be heard on many recordings, especially pop music from the 1980s. The monotimbral, 16-note polyphonic DX7 was the moderately priced model of the DX series keyboard synthesizers that included the larger and more elaborate DX1 and DX5; the feature-reduced DX9; and the smaller and not directly compatible DX100, DX11, and DX21. Over 200,000 of the original DX7 were made, and it remains one of the best-selling synthesizers of all time.