Zoë Blade's notebook

Yamaha DX21

DX21 tech specs

  • Released: 1985
  • Company: Yamaha
  • Type: FM synthesiser
  • Polyphony: 8 voices
  • Timbrality: Duotimbral
  • Operators: 4
  • Audio out: Stereo pair
  • Control: MIDI
  • Display: 16×2 character LCD
  • Features: Chorus
  • User programs: 32
  • Preset programs: 128

The DX21 was an FM synthesiser made by Yamaha in 1985, followed the next year by two minor variations, the DX27 and DX100.

It has only four operators for each of its eight voices, less than the popular DX7's six operators for each of its sixteen voices.

Its envelope generators are simplified too, only slightly more complex than the popular ADSR variety. This is arguably a good thing when you're trying to wrap your head around programming it. Essentially the sustain can also slowly fade out, offering a tad more realism (only organs have an external energy source sustaining a note indefinitely; other acoustic instruments play notes that slowly fade with entropy).

As with almost all hardware FM synthesisers, its small interface warrants using an editor/librarian such as 4-Op Deluxe.

The DX21 series was later superseded by the TX81Z series, which added other waveforms as starting points.


DX27 & DX100 tech specs

  • Released: 1986
  • Company: Yamaha
  • Type: FM synthesiser
  • Polyphony: 8 voices
  • Timbrality: Monotimbral
  • Operators: 4
  • Audio out: Stereo pair
  • Control: MIDI
  • Display: 16×1 character LCD
  • User programs: 24
  • Preset programs: 192

The DX27 was a cheaper, monotimbral version, lacking the DX21's built-in chorus effect.


The DX100 was an even cheaper version with miniature keys, hooks for a guitar strap, and the ability to run on batteries. Although it may not look as professional, it was used by several notable musicians.



I love the "Solid Bass" preset. I can tell you now, 'cos I've used it so much that I don't care if somebody else uses it. I don't really need sounds in a keyboard, I just need a trigger mechanism for the samples. I don't use many synth sounds, 'cos to me they sound fake and they sound too clear. "Solid Bass" is kind of dirty.

— Mark James (The 45 King), 1989[1]

I've had Matrix 12 filtering applied to the [DX100] to give it a completely different feel. The board was almost destroyed in the process. It was like "let's see what we can get away with". It breaks down a lot, but when it works it works, and it's my sound, it's part of the Rhythim Is Rhythim sound. And, like my American Express card, I don't leave home without it... You're not going to get beautiful string sounds out of it, but for bass sounds I've got the fat filter sound. In a little keyboard like that, it's so funny.

— Derrick May (Rhythim Is Rhythim), 1990[2]

It's really noisy, and some of the presets are so horrible, but the bass sounds are wonderful, especially on things like the "wood piano". By mixing that with the Minimoog, you can get the ideal bass sound, with both warmth and bite.

— Jon Marsh, The Beloved, 1993[3]

Notable users




  1. "45 Kingdom" Simon Trask, Music Technology, May 1989
  2. "Techno Rhythim" Simon Trask, Music Technology, Nov 1990
  3. "Dearly Beloved" Phil Ward, Music Technology, Mar 1993
  4. ~~ rephlex ~~ aphex ~~ drn ~~ Ben Middleton, alt.rave, Oct 1992
  5. Aphex Twin SYROBONKERS! Interview Part 1 Dave Noyze, 2014
  6. "Future Shock" Simon Trask, Music Technology, Dec 1988
  7. "Mixing up the motor city" Rob Green, The Mix, Apr 1995
  8. "The Magic Circle" Phil Ward, Music Technology, Jun 1993
  9. "Music of Spheres" Nigel Humberstone, Sound On Sound, Apr 1994
  10. "The Techno Wave" Simon Trask, Music Technology, Sep 1988



DX27 / DX100


Deep dives



FM synthesisers: Yamaha DX21 | Yamaha DX7 | Yamaha TX81Z