Image: Ludo, CC BY 2.0 — via Wikimedia Commons
Yamaha DX21
| Category | Electronic (FM synthesizer) |
|---|---|
| Country of origin | Japan |
| Classification | digital synthesizers using frequency modulation synthesis, synthesizer model |
| Wikipedia | en.wikipedia.org |
| Wikidata | Q55638028 |
Overview
The Yamaha DX21 is a four-operator FM synthesizer released in 1985 as an affordable companion to the company’s six-operator flagship instruments. It offers eight voices of polyphony, bitimbral split or layer operation, on-board chorus, and 128 patch memories. With its full-size 61-key keyboard, simple performance controls, and accessible price, the DX21 brought the distinctive bright, percussive voice of mid-1980s FM synthesis within reach of home musicians, project studios, and educational programmes.
Origin & History
Yamaha launched the DX21 a year after the influential DX7, as the demand for FM synthesis in popular music expanded rapidly. The four-operator architecture used in the DX21 — and shared with the DX9, DX27, and DX100 — provided a simpler engine than the six-operator DX7 but retained the recognisable FM sonic character. The bitimbral split/layer feature was unusual at the price point and gave the instrument extra value for working musicians who needed two patches simultaneously without buying a second keyboard.
How It’s Played
The DX21 is played from a 61-key non-velocity-sensitive keyboard, with patches selected and edited via the front-panel button matrix and small LCD. The four-operator FM engine offers eight algorithms, envelopes per operator, and basic LFO modulation. Bitimbral operation lets the player split or layer two patches across the keyboard, and the on-board chorus thickens leads and pads. Cassette and MIDI bulk-dump support patch storage and exchange.
Cultural Significance
The DX21 is part of the wider story of how FM synthesis filled the world’s home studios and educational settings during the second half of the 1980s. While serious players often gravitated toward the six-operator DX7, the DX21 and its four-operator siblings provided much of the sonic vocabulary that taught a generation of programmers the basics of FM synthesis. Its bell, electric piano, and brass voices remain instantly evocative of the era.
Related Instruments
- Yamaha DX1 – flagship six-operator sibling
- Yamaha Reface – modern compact DX revival
- Yamaha CS-80 – earlier analogue flagship
- Korg Poly-61 – contemporary affordable polysynth
- Roland JX-8P – contemporary analogue rival
Frequently Asked Questions
Is the DX21 four-operator or six-operator FM?
Four-operator.
Is it velocity sensitive?
The keyboard is not velocity-sensitive; the engine accepts MIDI velocity.
How many patches does it store?
128.
