Zoë Blade's notebook

The Digital Sequencer

The Digital Sequencer is, as its name implies, a digital step sequencer, designed and built by Ralph Dyck in the mid 1970s. It impressed Roland enough that they hired him, and used it as the basis for their own digital sequencers, the MC-8 and MC-4.

Technically, it's a step sequencer, because you don't play the notes in realtime while recording them. Instead, you step through the notes, entering one at a time via a numeric keypad. This is in contrast to the MC-8 and MC-4, which allow either method.

However, in all other regards, The Digital Sequencer is more like a non-step digital sequencer. The notes and rests can be arbitrary lengths, not just multiples of sixteenths, as the sequencer simply counts individual clock ticks — there is no coarse grid of sixteenths overlaid on top of the fine grid of individual ticks. Similarly, it remembers a single list of all the notes combined — they're not grouped into patterns, each a bar long, that you can toggle between. This is far more flexible, albeit also more time consuming, than programming a TB-303 or TR-606... not that they existed yet.

The Digital Sequencer was one of the first computer-controlled sequencers, although the EMS Synthi Sequencer 256 beat it by a few years, and even let you play the notes via its keyboard. It's not surprising that the digital sequencer was independently invented in different countries: it was the logical next step for sequencing once microprocessors were available on the market.

How The Digital Sequencer stored notes would form the basis of not just Roland's MC series, but also their descendants, MIDI sequencers as a whole. Compare Creator or Cubase's note list with The Digital Sequencer's program sheet. It's essentially the same thing, with the addition of polyphony (which is really just interlacing Note On and Note Off events, afforded by MIDI's packet switching), multiple tracks, multiple channels, and other kinds of events besides turning notes on and off.

As far as I can tell, Dyck invented tape sync, by frequency-shift keying the sequencer's ticks.[1] With the MC-4 (and modded MC-8),[2] Roland then used that as the basis of the rather more straightforward DIN sync, which in turn formed the basis of the MIDI clock.

In short, The Digital Sequencer was very influential, and a direct ancestor to basically every DAW.


I had no knowledge of any microprocessor system at all. I built up my sequencer a function at a time as they became necessary. Just trial and error. Eventually I had enough breadboarded modules to put them in a "proper" housing. By then I had most of the building blocks of my system. I had a modular synth that I built, so testing was easy and I had tons of drive. I had a vision as to how it should work, and built modules until it did! It was all based on logical needs, necessity, you know? The master plan was all in my head. If you saw the schematics, you would shake your head.

— Ralph Dyck, 2010[1]


  1. "Exclusive Interview With Ralph Dyck, Godfather of the MC-8" Peahix, Jan 2010
  2. "Roland MC-8 MicroComposer (Retro)" Chris Carter, Sound On Sound, Mar 1997



Digital sequencers: MC-4 | MC-8 | The Digital Sequencer