The Yamaha DX7 is a FM Digital Synthesizer manufactured by the Yamaha Corporation from 1983 to 1986. It was the first commercially successful digital synthesizer. Its distinctive sound can be heard on many recordings, especially pop music from the 1980s. The DX7 was the moderately priced model of the DX series of FM/PM keyboards that included DX9, the smaller DX100, DX11, and DX21 and the larger DX1 and DX5. It is often claimed that over 160,000 DX7s were made, and it remains second best-selling synthesizer of all time, after Korg M1 (1988, 250,000 units sold).
Tone generation in the DX7 is based on linear frequency modulation synthesis (FM), based on research by John Chowning at Stanford University. The DX7 was known for precision and flexibility of its bright, digital sounds, which were much clearer than those of the analog synthesizers that preceded it. The DX7 is well known for its electric piano, bells, and other "struck" and "plucked" sounds which emphasize complex attack transients. It is capable of 16-note polyphony. While the instrument is monotimbral, it is notable how the sound of a single DX7 patch can change either subtly or wildly along the length of the keyboard or when played with different velocities. The DX7 features 32 algorithms, each being a different arrangement of its six sine wave Operators, allowing for a great deal of programming flexibility.
Read more about Yamaha DX7: Programming, MIDI, Variants, Software Emulation, Program Piracy, Evolution of FM Synthesis