Zoë Blade\'s notebook

Yamaha DX7

DX7 tech specs

  • Polyphony: 16 voices
  • Outputs: Mono
  • Operators: 6
  • MIDI: Yes
  • Display: 16×2 character LCD
  • User programs: 32

The DX7 was an FM synthesiser made by Yamaha in 1983.

There were several variations of this synth. Prototypes, organs, and preset-only piano-styled stage keyboards aside, these included the DX1, DX5, and DX7. Out of these, the DX7 was the simplest, the comparatively cheapest, and by far the most popular.

All three models have six operators (oscillators and envelope generators) per voice. The DX7 has sixteen voices, while the DX1 and DX5 have thirty-two, by combining two sets of oscillator and envelope generator chips.

Further taking advantage of their digital nature, Yamaha gave these synths envelope generators that are much more versatile (and therefore harder to learn) than the conventional ADSR kind. They're more "attack, first decay, second decay, sustain, release"... although less prescriptive, as you can make subsequent levels higher than the first.

To make these synths even more versatile and complex, when it comes to using the pitch value to affect various parameters, this value can form a nonlinear curve, so instead of just forming a straight line on a graph, it can curve up or down either side of an arbitrary point.

FM synthesis is quite different to subtractive synthesis, more like an advanced version of additive synthesis. This means it can take a while to first wrap your head around it. But I think it has a somewhat unfair reputation for being very difficult to learn because, taking advantage of these synths being digital, Yamaha made the envelope generators and pitch tracking more versatile than anything else people were used to, so they had to learn three new things at once: FM synthesis, complex envelope generators, and nonlinear pitch tracking.

On top of that, in order to keep these mass produced synths anywhere near affordable, the user interfaces had to be cut down to menu diving nightmares, where you can only edit one parameter at a time. And on the DX7 and DX5, you can only see one parameter at a time, too.

It's not only useful that you can play all three over MIDI, it's essential that you can program them over MIDI too, preferably via an editor/librarian program on a home computer with a big, friendly screen that can show you everything at once. Making the DX7 respond to MIDI control change values, and all three models send and receive programs over MIDI, was impressively forward thinking considering that home computers with GUIs only became available the following year, let alone software for them that could edit synthesiser patches.

It's hardly surprising that most people stuck with the presets. As it's quite likely they would have done that anyway, even if given a more intuitive interface, the added versatility may well have been the wiser choice. The presets really do show off the abilities of FM synthesis. Compared to most of the analogue synthesisers that came before them, these three digital ones were much more playable: polyphonic, velocity sensitive, and filled with really expressive preset sounds. They were real performance instruments for musicians who could play.

There's a reason the DX7 was a large part of the sound of the 1980s.

After tentatively trying out a cheaper version with four operators, the DX9, Yamaha then offered a whole series of 4-Op FM synths, starting with the DX21.







Deep dives



FM synthesisers: Yamaha DX21 | Yamaha DX7 | Yamaha TX81Z