Arturia PolyBrute 12

Arturia’s PolyBrute has gained six voices and a lot more besides.

Very occasionally, a manufacturer decides to throw everything it knows into the creation of a flagship synthesizer. Eschewing simplicity and intuitivity (did I just invent a word?), the designers’ task is to make everything possible, even if this means that the musician will have to think about how to program and play the resulting instrument. Sometimes, the additional complexity means that almost no‑one will ever plumb its depths, and many of its advanced features will never be appreciated by the masses unless, perhaps, one of its more interesting sounds is plastered over the latest TikTok sensation. On other — perhaps rarer — occasions, the hardware and software design is clever enough to reveal the underlying power while avoiding the worst excesses of arcana, allowing the likes of you and me to understand what’s going on and to discover new sounds and performance possibilities for ourselves. All of which brings us to the PolyBrute 12.

Under Pressure

Much of the PolyBrute 12 is the same as its predecessor, the PolyBrute, which I reviewed in SOS October 2020. Four years ago, I found this to be a superb synthesizer and, in my view, it has long been overlooked and underrated, perhaps for no reason other than because players don’t expect a polysynth of these capabilities from what many view as a manufacturer of soft synths and low‑cost monosynths. So how does the PolyBrute 12 exceed the capabilities of its predecessor? Surprisingly, there are just two significant differences. But they’re goodies.

Let’s start with the most obvious; the PolyBrute 12 has twice the number of voices as its predecessor, and hence twice the maximum polyphony. Nearly 50 years ago, the Prophet 5 showed that you can create a superb synthesizer with as few as five voices, and there are some excellent modern instruments such as the Prophet 6 and Oberheim OB‑6 that still do very well with just six. Nonetheless, increasing the number of voices extends what you can do with a polysynth, so we shouldn’t underestimate the importance of this. Whereas you have to be quite careful to avoid note stealing on the six‑voice PolyBrute, you can play more naturally on the 12‑voice PolyBrute 12. I experienced the same improvement in 1987 when I replaced the six voices of my Roland JX‑8P with the 12 of a Super JX‑10, the latter of which remained my big analogue polysynth of choice for more than a decade. Mind you, the JX‑10’s appeal wasn’t just that it had more voices; its velocity and aftertouch‑sensitive keyboard was exceptionally playable, making it the most expressive analogue polysynth of its era. All of which brings us to the second upgrade that defines the PolyBrute 12.

Despite its importance, you won’t see much evidence of this on the synth itself. The only visible difference is a small, extra pane in the column of voice management and control selectors to the far left of the control panel. This includes a single button annotated Aftertouch, which selects between three options. The first of these is Mono (more correctly called Channel) aftertouch, which is by far the most common implementation, and the only form offered on the original PolyBrute. When you lean on any key after it reaches the bottom of its travel in this mode, every note being played at that moment is affected equally, whether to add growl or vibrato, or affect the loudness or brightness... or whatever else you have programmed aftertouch to do. The second is Polyphonic aftertouch (or Poly‑AT), and this allows you to control individual notes when you press down on them, making it possible (for example) to swell or add growl to a single note in a chord, or to add vibrato to the upper notes while keeping the lower ones steady, and much more. Finally, there are the Alt modes that you select using a combination of the third Aftertouch option and the screen/menu system. As far as I’m aware, these modes are unique to the PolyBrute 12, so they appear to represent a very rare thing: a genuine development in the field of keyboard performance.

The Alt modes have been made possible by the development of a new keybed that knows the position of each key in its travel. Arturia have then made use of this in three ways to provide different ways of articulating individual notes while playing. The first of these is called FullTouch AT. With this selected, a note is triggered as soon as you start to depress a key (ie. at the very top of its travel) and, while the velocity is still measured correctly, the rest of the key’s vertical travel determines the polyphonic aftertouch value, from zero at the top to maximum when the key is fully depressed. So, like traditional Poly‑AT, you have three values generated when you press a key: the note number, its velocity and its aftertouch, albeit with a new method employed for generating the values for the last of these.

The second Alt mode is called FullTouch AT > Z, and this adds a further dimension of expression. Again, the note is triggered at the top of the key’s travel and velocity is correctly handled. And, again, the aftertouch value is determined by the position of the key in its vertical travel. But now the traditional aftertouch sensor at the bottom of each key’s travel is employed to generate the ‘Z’ modulator that you more usually obtain by moving the Morphée pad down and up. (No, I don’t mean ‘up and down’ — think about it!)

The third mode is FullTouch Env > AT, and this is the one that’s going to cause confusion, not least because the manual doesn’t describe it fully. (A lack of detail was a fault with the original PolyBrute manual, too.) Having spent hours trying to work out what was happening, I admitted defeat and contacted Arturia. It turns out that, when designing sounds to take advantage of FullTouch AT...