A tour of MPE, with apologies to Roger Linn

This article coincides with the publication of the MPE specification, which I facilitated and helped to write. If you register with The MIDI Association, you can download it free from here.

Roger Linn didn’t invent the drum machine, but he did make one of the first examples of a very good one. Drum machines began their lives in the 1960s, as little panels of buttons that gave organists a Latin rhythm to play against. The sounds of the day were built entirely out of snippets of simple waveforms and chuffs of filtered noise. These camp little drumbeats were subverted by Kraftwerk and post-punks, but hardly entered the cultural mainstream. Witness the Ace Tone Rhythm Ace.

When Donna Summer recorded ‘I Feel Love’ in 1977, the kick drum was provided by a (presumably both bored and anxious) real drummer; everything else on the percussion track was hand-crafted using a huge synthesiser. The result prefigured a coming of age for these early machines. Those who were present at the recording session routinely discuss what a pain it was to piece the single together, part by part. It was revolutionary in terms of its sound, and helped to cement George Moroder’s legacy as a producer, but the painstaking techniques he had developed to make such music possible would not catch on.

The LinnDrum, which arrived in 1982, actually sounded somewhat like a drum kit. Each drum could be tuned and tweaked like a recorded kit, to punch nicely through the mix. It, and contemporaries made by Roland (the company that Ace Tone became), Oberheim, and later others, underpinned the backing tracks of the synthpop music of the 1980s. These artificial instruments were intended to sound natural, but they were often programmed in a context that deliberately emphasised their inhuman nature. The machines began a long-lasting aesthetic of meticulously-layered, robotic backing tracks, where often the only live performer on the recording was the vocalist.

None of this would have been possible on such a scale without MIDI, a standard devised for interconnecting early synthesisers, which propelled this music into the mainstream by providing an easy way for drum machines, bass synthesisers, and other instruments to play their musical patterns in lockstep.

In person, Roger Linn has become fairly ambivalent about the Eighties, about the musical revolution he helped to create, and his obscurity as an inventor beyond the tiny music technology industry.

MIDI, too, has struggled with its reputation as a protocol for making robotic music. The early Nineties brought a thing called General MIDI, which enabled synthesisers to work more seamlessly with each other and computers so that, for example, orchestral music written to be replayed on one device would sound right on others. The unintended consequence of this was a craze for polyphonic ringtones about ten years later, when this technology became cheap and commoditised enough to end up in mobile phones. It has not been easy to foment much strategic consensus in the music tech industry beyond General MIDI, but that hasn’t stopped us trying.

Music tech has long had a problem where the tail wags the dog. The success of MIDI means that the form and function of electronic instruments has, for years, been driven by what the specification does best, and not the other way round. This is why, after a Cambrian explosion of exotic devices in the Eighties, all controller keyboards now look precisely the same: why there are always eight control knobs, and a data slider, and wheels marked ‘pitch’ and ‘mod’.

Why isn’t MIDI capable of supporting other approaches: of conveying and shaping natural human expression in all its variety? Well, it sort of is, but that’s not how it’s used. The limits of creativity are no longer determined by channel count, processing power, or data bandwidth. Rather embarrassingly, they’re driven by the cultural assumptions of a technical specification that’s more than 35 years old, and so entrenched in its own status quo that it cannot easily be changed.

This is why ROLI ran into difficulty about six years ago, when we tried to connect our prototype instruments to existing synthesisers, and quickly realised that not many people had given the problem of musical expression much thought. If every note in your performance needs to respond to a different movement of a user’s finger, there are technical workarounds that can achieve this. But, as hardly any instruments could generate such rich data, hardly any synthesisers could be made to work with it.

Other companies who had made expressive instruments had written their own synthesiser software, and ROLI got the situation under control by following the same path, and making Equator. We realised early on that customer confidence equals sales: that, only by building strong relationships with other companies, and making an ecosystem where our stuff would work, would we prosper.

A few synthesisers made by other people were actually ready to do the unusual things that we had to do, such as pitch-bending and swelling individual notes in a chord. After a couple of false starts trying to reinvent MIDI to fit our problem, we reinvented our problem to fit MIDI. In 2015, we started working with the MIDI Manufacturers Association to put together a specification called MPE [MIDI Polyphonic Expression]. This is a common way of allowing expressive controllers and synthesisers to communicate.

Aside from us, this has helped other hardware manufacturers to sell their instruments. Keith McMillen, Haken, Madrona, Eigenlabs, and Roger Linn benefit from MPE. It’s also helped makers of innovative synthesisers, such as Audio Modeling, find a small but interested market for their novel instruments. And it’s been supported by companies as far-ranging as Bitwig and Apple. But driving consensus among around twenty different vested interests has taken its time, and the specification has finally been published today, some three years later. You can find it and download it freely from the link at the top of the page.

If you already make electronic music, you probably won’t notice MPE compatibility slipping into the newer devices you use. This was one of the intentions. The other is that, if you do decide to go out and buy a Seaboard (if you haven’t already), there are a whole host of companies that have embraced MPE, and the Seaboard will work with their equipment.

Perhaps in an effort to produce a more interesting legacy, Roger Linn produces his own expressive instrument, the aptly-titled LinnStrument. He has been a champion of MPE since its pre-MIDI days. In his quest to imbue electronic music with the humanity that he unintentionally helped it to divest thirty years ago, he is making liberal use of the slogan ‘Stop using on-off switches!’

It’s my pleasure to say that I’ve stood on the shoulders of Roger Linn and others, in chairing the MPE Working Group, in writing and endlessly revising about 80% of the specification, and in speaking about it in various places. In glorious anonymity, it has been published today.

Now that you can afford to do so, and there’s a widely-supported and freely-published way of doing it, it’s become easier than ever to take Roger’s advice.

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