MPE Innovators Luminary ROLI explain the benefits of five dimensional control

From expanding the potential of MIDI control with the Seaboard, to a series of snap-together Blocks, ROLI – now re-christened ‘Luminary ROLI’ remain at the forefront of 21st century musical expression. We recently caught up with the company to go deep on their latest movements, and to learn more about their multi-dimensional philosophy… 

Multidimensional Polyphonic Expression (MPE) has transformed how many of us think about MIDI control. Previously, triggering samples, performing virtual instruments and exploring the nuances of synthesis was a relatively static affair, with our trusty pitch and modulation wheels the only way to alter sounds. MPE instruments – with their five dimensions of control per-note (as opposed to global adjustments to the whole MIDI signal) allow for a much wider scope on which to compose and create.

Spearheading the MPE revolution, ROLI released their squidgy-keyed Seaboard – one of the most successful MPE instruments ever, before a decade’s worth of exemplary control surfaces and forward-thinking ideas cemented the company as one of the industry’s most pivotal. Following a re-brand last year, the company – now dubbed ‘Luminary ROLI’ –  continue to implore everyone to dive deep down the well of multi-dimensional expression. We had a chat with the company’s Principal Sound Designer, Rafael Szaban, to learn more about the beauty of MPE… 

1: Can you explain to us how using unique MPE control surfaces like the Seaboard explode the possibilities of MIDI control?

In a nutshell, MPE controllers like the Seaboard provide expression as seen in various acoustic instruments, where we have intuitive, direct and powerful means of expressing the sound with our fingers without the usual limitations of standard MIDI controllers. It’s about bringing the natural way in which acoustic instruments behave to the electronic MIDI controller, as much as possible. This is done via five fully polyphonic ‘dimensions of touch’  – velocity (STRIKE), polyphonic pitch-bend (GLIDE), polyphonic slide along the key (SLIDE, which is CC74 for the uninitiated), polyphonic pressure (PRESS) and polyphonic velocity release (LIFT).

2: So, MPE is fundamentally about enhancing musical performance first and foremost? 

To make a simple comparison, we can make a very powerful and expressive sound on a traditional MIDI keyboard by utilising velocity, aftertouch, a modulation-wheel, pitch-wheel, perhaps a pedal as well, we could even add some MIDI faders assigned to all sorts of parameters in the sound. On the surface it looks like a powerful set of controllers that we can use during a musical performance. 

The problem is that all of these controllers are separate entities, they are disjointed, they require that we lift at least one hand to access them, but what if we desire to keep on playing with both hands uninterrupted and still have maximum expression? Not possible. Moreover, many of these controllers will affect all the notes played, so for example, the pitch-wheel when used will affect all the notes we play, so will the modulation-wheel, and the pedal, and the faders. This is not how acoustic instruments capable of polyphonic playing behave.

ROLI seabord

3: So per-note expression smashes what conventional MIDI keyboards are capable of?

Bending a string on an acoustic guitar bends that string only, but our pitch-wheel bends all of the notes we play. This is the fundamental limitation of standard MIDI. Fortunately, this is where MPE comes to the rescue. It offers a much smarter way of interacting with electronic sounds by offering fully polyphonic expression, where each note is independent and crucially, directly accessible by each finger. We no longer have to interrupt our playing in order to lift one hand and access a pitch-wheel, or the mod-wheel. We do it right on the key. Each key independently. Or all keys at once. It’s up to us. 

We have the choice. But there are more subtle but still fundamental differences. For example, MPE controllers like the Seaboard that are based around continuous-pressure are capable of expressive sounds that are not possible with aftertouch, which has been the mainstay of all good, traditional MIDI keyboards. Aftertouch allows us to use pressure on the keyboard to add expression, but the way aftertouch works (be it the channel/mono-aftertouch or the more rare polyphonic-aftertouch) is very jerky. The response is almost like an on-off switch, it comes on very suddenly. We press down on the keys and nothing happens until suddenly something happens. It’s difficult to control it in a natural manner. And again, this is not how for example a string behaves when we bow it or when we blow into a flute mouthpiece. Here, the bow and the breath is smooth and the intensity of the bow/breath is very easily controllable by the musician in this ‘continuous’ manner. This is what continuous-pressure is about. It offers the same liquid smooth means of expression via pressure.

4: So continuous pressure allows notes to be manipulated just like their acoustic brethren?

Yes, Suddenly, all manner of sounds are possible. Acoustic imitative sounds come alive. Strings, reeds, woodwinds, brass, voices, all come to life through the use of continuous-pressure. And because this type of continuous-pressure (PRESS in Seaboard speak) is fully polyphonic, it also transforms all manner of purely electronic sounds

5: What does this greater directional freedom mean for synthesis?

Simply put, it’s a whole new world. It’s a new way of bringing life to purely electronic sounds. The potential for beautifully ‘alive’ sounds is immense. From truly abstract electronic sounds to imitative hybrid electro-acoustic sounds, MPE allows intuitive and powerful expression not possible before. This is where powerful synthesis engines shine and come to life as we use many synthesis parameters and assign them carefully to all those 5 dimensions of touch. But we don’t have to even strive for some complex and unique sounds here. Sometimes simple is just as good. For example, take the average ‘analog’ style pad or brass patch. Playing a sound like this on an MPE instrument allows us to imbue it with tiny pitch detuning, pitch imperfections, fluctuations in tone, which add that ‘organic’ analogue quality. If this floats your boat, you will be in expressive heaven.

6: Is there a downside though, does learning to work with MPE require more care and attention? 

Because all five dimensions of touch interact with each other as we play, the sounds need to be carefully balanced. How it’s done depends entirely on the type of MPE controller we have, as each will require a slightly different approach to finalising of our sound, where we balance it to the specific playing surface of the actual MPE controller and our preferred playing technique. And so a sound made for the Seaboard RISE will require a different approach than the same sound made for the Linnstrument. And this is how it should be since each MPE controller is really a unique instrument and the sounds need to be fine tuned to each separately.


7: Your synth, Equator 2 certainly seems to be the most MPE-aimed engine we’ve ever seen. Can you talk us through its history? 

Equator started its life as a purpose made MPE software plugin. Let’s go back in time however since the vision behind Equator was to run it also as a DSP engine on the Seaboard GRAND. So Equator was the first MPE software synth (MPE wasn’t even born back then) that existed as a DSP engine in a hardware MPE instrument and as a VST/AU plugin. Now we have Equator 2 which took the best bits from Equator 1 and added a huge list of new features, redesigned features, as well as an immense new sample content, including samples of some truly unique analogue synths. 

So at each juncture, Equator 2 was being designed with MPE in mind. This translates to one immediate and unique feature: the expression curves. The ‘expression-curves’ are the centrepiece here. As you look at Equator 2 you are immediately greeted by a set of five expression curve ‘busses’ right in the middle of the GUI. Each ‘bus’ has four separate expression curves. Why is this so important? The expression curves allow us to manipulate the sound, to fine tune it to the playing technique and the actual MPE instrument we are using. 

In order to balance the sound through this complexity we need to shape it, that is, we need to shape the modulation we have assigned everywhere so that the sound is musical and playable. For example, pressure and release velocity (PRESS and LIFT) are intertwined and in order to manage this combo of pressure vs release velocity we need specific expression curve shapes. The same applies to sliding along the key wave on the Seaboard RISE, or how we interact with continuous-pressure, or how we use the ribbons on the RISE. In each example custom expression curves are needed. And so, they play centre stage in Equator 2.

8: Beyond the movement controls, its synth engine is particularly impressive in its own right. Can you talk us through them?

Equator 2 is loaded with powerful synthesis options from a deep Wavetable synthesis engine, 6-op FM where even samples can be used as FM sources, sample playback, to granular synthesis with some unique features like the ability to trigger samples with LFOs and envelopes. This allows for some very cool pseudo wave-sequencing sounds in a granular patch. 

The actual flexibility of the whole engine is impressive as well, with each oscillator having its own resonant multi-mode filter followed by two non-resonant LP and HP filters which can all be sent to two master resonant multi-mode filters, or not (that’s eight polyphonic resonant multi-mode filters and 16 non-resonant filters!) The signal path is very flexible with a mixer that allows various signal permutations. This is all very deep, but it is key to some very complex MPE sounds, which are all made that much sweeter by up to 16 effect modules!

9: Do you think that range of shaping control, and the depth of its engine, are Equator 2’s main USPs?

I actually think the main selling point for me is that despite all this power, Equator 2 makes it very easy to access and use. The way we can ‘draw’ modulation around each dial, the way we can explore outlandish MPE sounds by layering up to six oscillators, where one can be a Wavetable sound, another could be using a sample of an analogue synth, two more oscillators could function as an FM-pair, yet another be a granular sound, all of this could be happening in one preset. This is so powerful;, especially as we add the expression curves that can shape this ‘wall of sound’ to our liking. This is rather special in my mind.

ROLI Equator