Yamaha DX21

DX21
A Yamaha DX21 synthesizer shown along with various 90s and 2000s-era groove machines.
ManufacturerYamaha
Dates1985
Technical specifications
Polyphony8-voice
TimbralityBi-timbral
Oscillator4-Operator, 8 algorithms
Synthesis typeFM
FilterNone
Aftertouch expressionYes, via MIDI only
Velocity expressionYes, via MIDI only
Storage memory128 patches, 16 performances
EffectsChorus
Input/output
Keyboard61 key
Left-hand controlModulation, pitch bend
External controlMIDI (In, Out, Thru)

The Yamaha DX21 is a digital controlled bi-timbral programmable digital FM synthesizer with a four operator synth voice generator which was released in 1985 by Yamaha. It uses sine wave-based frequency modulation (FM) synthesis. It has two FM tone generators and a 32-voice random-access memory (RAM), 32 user voices and 128 read-only memory (ROM) factory preset sounds. As a programmable synth, it enables users to create their own unique synthesized tones and sound effects by using the algorithms and oscillators. The instrument weighs 8 kg (17.6 lbs). On its release, it sold for $795.