The instrument
The DX7 is a milestone in synthesizer history. It achieved a great success over the years and has now a cult status among players and aficionados, but we must remember that in 1983 it wasn't a groundbreaking instrument, rather a mix of the latest technologies already available. It was the first successful digital synthesizer, selling more than 200'000 units. FM synthesis, generating sounds via frequency modulation, was developed by John Chrowning at the Stanford University in the 1960s. Yamaha licensed the technology. The first commercial FM synthesizer was the Yamaha GS1.
Details
The DX7 FM engine has 6 operators, 32 algorithms, pitch envelope generator and keyboard scaling. Modulation can be achieved through foot switches, breath controllers and keyboard aftertouch. Voices cannot be stacked and a basic MIDI implementation is provided, although many later expansion will add these features. He is 16-voice polyphony, had a monotimbral, 6 digital sine wave operators per voice, 32 patching algorithms, 1 pitch envelope and 6 amplitude generators per voice, aftertouch and velocity expressions.