MPE: The Future of MIDI and Electronic Musicianship

What’s the problem with the guitar? Well, if you’re alright with quick note decay and tuning it constantly, then nothing really. The piano? It’s a perfectly fine instrument, as long as you’re okay with really only making one sound and only being able to play it at home. The violin? Have you ever actually tried just picking up a violin and playing something?

Read a little page called “What’s Wrong with Current Instruments” buried deep on the Roger Linn Design website, and you’ll realize just how flawed the instruments we grew up playing in our living rooms and middle school orchestras really are.

Roger Linn is a man who has spent his career building solutions to problems the music world didn’t even know that it had. He innovated the sample–based drum machine with the LM–1 Drum Computer in 1980 and the modern sampler with the MPC 60 in collaboration with Akai in 1988. These would help change pop, hip–hop, and dance music for good.

During a recent email exchange of ours, Linn noted that, “Ever since popular music has been produced entirely electronically — such as electronic pop or hip–hop — the concept of an instrumental solo has disappeared. It existed in all previous forms of music but now it’s gone.”

To Linn, this anomalous period in musical expression is largely thanks to our available instruments. Sure, the guitar, trumpet, piano, violin, drum, and of course the human voice may have their limitations, but they also have physical qualities that act as a natural avenue for expression.

The only instrument available to electronic producers is the MIDI controller, and the MIDI controller is emotionally unintelligent in comparison to its acoustic rivals. As Linn notes, the MIDI keyboard or drum pad is really just a group of on/off switches.

Press the key, the notes sounds. Release the key, the note turns off. You can use velocity to affect how loud it is and fiddle with the pitch and modulation wheels, but that’s really about it.

It’s a problem inherent to MIDI, and one that Linn hopes MPE will solve. Well, Linn along with Apple, ROLI, Keith McMillen Instruments, and a host of other innovative companies.

What is MPE?

Multidimensional Polyphonic Expansion is basically a savvy utilization of the MIDI protocol, getting a lot of flexibility out of the dinosaur of a digital protocol by turning it on its head.

Typically, when you plug a MIDI keyboard into your USB port, it connects to a single MIDI channel and every change on that channel effects all of the notes. For instance, if you hold a chord and push the pitch wheel up, the whole chord will shift up in pitch.

MPE, on the other hand, uses a discrete channel per note. With a multidimensional keyboard like the ROLI Seaboard, that means you can hold down multiple notes and wiggle just one finger back and forth to change the pitch of just one note in the chord.

MPE, really and truly, was developed as a way to bring expressive maneuvers that are natural to acoustic instruments — specifically strings — to the world of electronic music.

The multidimensional aspect basically means that any note has three dimensions for expression. So, going with the Seaboard example, you can control one parameter by pressing harder or softer on the key, one by wiggling your finger to the left and right, and one by moving your finger forward and backward along the key.

MPE, really and truly, was developed as a way to bring expressive maneuvers that are natural to acoustic instruments — specifically strings — to the world of electronic music.

Each of those directional expressive capabilities should correlate intuitively to someone who has a background in, say, playing cello, and should prove simple for a mainly electronic musician to pick up.

But one of the amazing things about MPE is that you can push the boundaries of conventional expression as well. With a MPE–capable synth — like ROLI's Equator, Bitwig, or something cooked up in Max/MSP — you can assign any parameter to those individual dimensions.

That means you can play a synth line with a delay whose feedback amount is affected by how hard you play so that emphasized notes trail off for longer, low–pass filter cutoff going left and right for a easy control over a sound’s brightness, and LFO rate controlled by the placement of your finger on a key to quickly toggle between slow volume swells and tremolo madness.

But the MPE keyboard itself might just end up being a gateway into a new age of unseen electronic instruments. More on that in a bit.

Developing MPE

Over email, I recently asked one of the key software engineers behind the MPE protocol, Geert Bevin, why MPE is based in MIDI instead of just leaving the decades–old MIDI protocol in the dust.

He noted that MIDI is already ubiquitous in electronic instruments and DAWs, meaning that, “Very few products will take the effort to implement other protocols since there are too few interested users. And when there are not many products using a particular protocol, users will not adopt it.”

Does that mean that MPE is poised to become the future of musicianship in electronic production? There are no sure bets, but a coalition of heavy hitters and scrappy upstarts in the music gear and tech worlds have formed to rally behind the new standard.

Bevin is leading the charge on formalizing the MPE protocol after a conversation with ROLI at Winter NAMM in 2015. Under the MPE MMA working group, Roli has brought together the usual suspects like ROLI, Roger Linn Design, Haken Audio, and Bitwig with tech monolith Apple. Bevin wrote the first draft of the MPE MMA spec as part of the group.

Apple’s involvement could mean a lot of things for the future of MPE, but easy integration with iOS and Mac OS seem like modest and reasonable expected outcomes.

Once that protocol is established and released, Bevin expects “an explosion of MPE–capable instruments.” He predicts, “Once this explosion happens, many more musicians will get exposed to the joy of playing electronic music expressively and I expect this to significantly influence the music that is created over the next decades.”

The Instruments

As noted earlier, MPE provides a unique opportunity for new instrument designs, marrying the tenacious innovative spirit of Silicon Valley with the eccentricity that seems natural to the types who actually set out to design new ways of playing music.

Roger Linn Design LinnStrument and LinnStrument 128

The LinnStrument might just be the most consequential of all of the current MPE controllers, thanks to Roger Linn’s apparent knack for imparting a familiar form with near limitless possibilities.

Like Ableton’s Push controller and Novation’s Launchpad, the LinnStrument is a grid of small pads that can be mapped in any number of ways.

But unlike Ableton’s and Novation’s devices, the Linnstrument is not meant to interface with a production environment, but rather to get the player out of it and into the headspace of instrumental performance.

You use those pads to play notes, and they’re arranged with a logic that’s meant to appeal to guitar and strings players, with rows of notes related by semitones.

Linn notes that bending a note is as simple as sliding your finger across pads, but that its layout is conducive to “advanced performance techniques, like three–part sliding harmonies — something that makes the full use of MPE.”

The expressive element is really intuitive, with the length and width of the square pads acting like the type of X–Y axis that Korg uses on its own expression pads and the pressure on those pads acting as the attack– and pressure–sensitive Z–axis.

Geert Bevin was central to the development of the LinnStrument into the device it is today, developing its software from the core that Linn built. Linn considers Bevin his co–designer of the instrument.

The Linnstrument also comes in a smaller, more affordable version called the LinnStrument 128.

ROLI Seaboard

As alluded to earlier, ROLI's Seaboard may be the instrument that breaks MPE to the masses, thanks to its combination of that simple directionality and the traditional keyboard layout.

The Seaboard is a very sci–fi piece of equipment, with a squishy membrane that you play kind of like the video game controllers in David Cronenberg’s eXistenz.

The British firm started big and went small, releasing the Seaboard Grand back in September of 2015, which was a 61–key MPE keyboard. From there, it scaled down to the 49– and 25–key Seaboard Rise options, and just recently announced the 24–key Seaboard Block, which is bluetooth compatible making for quick integration with iOS devices.

That Seaboard Block is far and away the most affordable MPE controller on the market at $299. It’s still a lot steeper than Behringer’s bargain bin keyboard controllers, but cheap enough for the MPE–curious to get an access point.


The Eigenharp is another example of a new instrument designed specifically with the MPE protocol in mind, and boy is it something. Part wind controller, part controller with three–dimensionally sensitive buttons, the Eigenharps look like orchestral instruments from an episode of Star Trek: Deep Space 9.

There are currently three models available from the British firm: the Eigenharp Pico at £459, the Eigenharp Tau at £2,395, and the Eigenharp Alpha at £4,950. Each comes with an array of keys, mode button, and an expression strip, all on top of the breath pipe.

The Eignenharps come with their own native software and can also act as a controller. That’s to say that they aren’t just predominately MPE controllers, but they do all need a computer to run the software.

As Eigenlab’s website notes, the Eigenharp Alpha can “play and record loops, change scale and key, transpose, alter tempo, program beats, create arrangements, switch and layer multiple sounds, all while the musician is performing live on stage.”

Haken Audio Continuum

This is the first membrane controller that really hit the market, and Haken Audio’s Continuum can be seen as both a precursor to and a luxe version of ROLI’s offerings.

The Continuum is quite literally designed to expand the traditional idea of the keyboard instrument, with the full–sized version spreading across eight octaves, in comparison to the conventional piano’s seven.

The Continuum offers a very similar approach to dimensional control as the Linnstrument, but demarcates its membrane with a keyboard layout. This gives a familiar context for piano players (a shared goal with ROLI) while allowing for the easy glissandos, swooping grace notes, and expansive vibrato of Linn’s design.

Defining itself as truly future, the Continuum comes in red with an optional stand that would evoke yet another comparison to another work of sci–fi [editor’s note: it was Star Trek: The Next Generation].

Keith McMillen Instruments K–Board Pro 4

This one is still at that intermediary stage between getting backed on Kickstarter and hitting the market later this year, but Keith McMillen’s Berkeley–based firm is looking to expand its array of hyper–versatile, virtually indestructible controllers with an MPE keyboard.

What will ultimately set the K–Board Pro 4 apart from its most direct competition is the use of a firm silicon membrane that offers enough resistance to satisfy keyboard players used to the more conventional feel of a synthesizer keybed. This will theoretically facilitate better attack expression.

The K–Board Pro 4 will also be fairly reasonably priced at $599, with a minimal and lightweight design that seems aimed toward the working, performing musician. Its lack of moving parts theoretically contributes to long–term durability.

If KMI hits the nail on the head with the K–Board Pro 4 like it did the the QuNexus and the K–Mix, this may end up being that road–ready device that will last the laptop musician who likes playing keys longer than several of her laptops combined.

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