Arturia PolyBrute In-Depth Review

Arturia is still a relatively young manufacturer compared to the other big names in the industry. But, they have already rolled out a pretty solid line-up of synths in recent years. We’ve had the MiniBrute, the DrumBrute, the MatrixBrute, and now, we have the PolyBrute.

Despite having success with previous synths, the PolyBrute feels like another level; it’s big, bold, and ambitious. Arturia is indeed pitting themselves against the big boys with this one; let’s see how they stack up.

What makes the PolyBrute different?

Let’s start with the obvious. The PolyBrute is a polysynth, and Arturia’s previous Brute models were monosynths. A polysynth opens up a whole new world of harmonic possibilities; it allows you to play chords rather than being limited to single-note lines.

That’s not to say that a polysynth is inherently better than a monosynth; it just depends on how you want to use it. For example, with many synth basslines, you want that mono thing of each note cutting off the last, giving you that funky feel. But, if you’re going to create harmony with a monosynth, you are limited to things like tuning oscillators differently/independently. To an extent, you can approach playing a polysynth much more like a piano or regular keyboard, and that often makes them more appealing to new synth players.

Although the PolyBrute is based largely on the tried and tested Brute architecture, it does differ in some ways at the core of its sound generation.

So, let’s take a quick overview of what the PolyBrute has to offer. It’s a 6-voice bi-timbral polysynth with digital effects, but the signal path is entirely analog. The PolyBrute comes with 61 synth-action, velocity-sensitive keys with aftertouch. There are two analog oscillators, two LFOs with selectable waveforms, and one LFO with waveform shaping (three LFOs per voice).

Thankfully for some, the distinctive sound of the Steiner-Parker filter is still here, along with a 24 dB/octave ladder filter with distortion. Three envelopes are available, with two ADSR and one DADSR contour generators.

Being multi-timbral, the PolyBrute allows you to set up each sound in two states, A and B, simultaneously. The best thing about the two states is that morphing between them (in morph mode) can be a fantastic performance tool. Rather than switching between two sounds in a clumsy or mechanical way, it morphs smoothly. For example, if the oscillators in state A are tuned lower than those in state B, it won’t just blend the two pitches together. Morphing from A to B will let you hear the pitch change as it travels from lower to higher. This function goes some way towards making up for the relatively lacking polyphony. As a 6-voice synth, it’s not the most polyphonic synth available in its price range.

The digital effects offer almost 400 presets with over 700 preset slots. As expected, the PolyBrute has a 32-step arpeggiator and a powerful 64-step polyphonic sequencer. The usual pitch and mod wheels are present, along with a wooden ribbon strip, which looks and feels vintage and premium authentically. The more unusual modulation tool is the Morphee pad.

That’s what the PolyBrute is, in a nutshell, now we can take a deeper dive into each area of this massive synth.

The oscillators

As we said, there are two analog oscillators, and they differ slightly to the previous Brute synths. Arturia’s Brute monosynth oscillators offered four waveforms that came to be the foundation of the Brute sound. They featured a sawtooth wave with Ultrasaw, a Variable pulse wave with pulse wave modulation, a sub-oscillator with square/sine waves, and a triangle wave with Metalizer. Metalizer is wave-folding, which is a kind of distortion synthesis, somewhat similar to digital clipping.

Here’s how the PolyBrute does it a little differently:

The first oscillator offers sawtooth, triangle, and pulse waveforms. The Ultrasaw that was previously available with the sawtooth waveform is now gone. Also gone is the sub-oscillator, but the Metalizer can now be applied to all waveforms, not just triangle. However, there is a little bit of menu-diving to do so. Menu-diving aside, this oscillator setup comes with some give and take.

No doubt, some people, especially avid Arturia synth players, will miss the Ultrasaw sound. If you are one of those people, you can still get that thick, lush sound through detuning the oscillators. The upside is that the more versatile wave-folding options provide more unusual sounds and timbres, which give the PolyBrute real identity.

The second oscillator is without the Ultrawave and Metalizer functions. It compensates for this by maintaining the sub-oscillator from the classic Brute architecture, one octave below.

Oscillator one can sync to oscillator two, with more variation than you find on some other synths. Rather than just having a hard-sync button, a knob allows you to set the sync level from soft to hard with multiple stages in-between. The sync level does come in clearly identifiable steps, so it might be more of a sound design tool than performance sound shaping. What we mean by that is that you don’t get the smoothest transition between each stage.

Oscillator two can be used for cross-modulation as the modulator for FM synthesis. Doing so doesn’t always provide the most consistent sound, even with constant tuning. But, what it does give you is some more unusual tones to add to the PolyBrute’s arsenal.

As far as tuning goes, oscillator one is always locked to semitones, and oscillator two offers chromatic ranges as well as fine-tuning. Again, the difference between oscillators one and two conjure up some strange and interesting sounds. The stranger side comes when you start to modulate the tuning in various ways. There are plenty of options from major and minor scales to Phrygian and more exotic modes – not to mention portamento and glissando.

To give an example, you could modulate one oscillator strictly in fifths, while the other is locked to the Phrygian scale mode. The result can be a sublime mix of consonance and dissonance, and it’s often quite remarkable.

The oscillators, generally speaking, are very pleasing. There wasn’t really any doubt that they wouldn’t deliver a solid core sound, but with a few simple tweaks, they now offer something quite unique. Next to the oscillators is the mixer, with three inputs; oscillator one, two, and noise. The output of each can be sent to one or both filters in series, parallel, or something in-between.

The filters

As we said earlier, there are two filters, a Steiner-Parker filter and a ladder filter. Before we get into them, there is one noticeable restriction from MatrixBrute to PolyBrute, which is that you can’t change the filter slope. The thing to remember is that each synth is different, and an omission isn’t always a downgrade. What you get with the PolyBrute is the best compromise between filter versatility and simple workflow.

Starting with the Steiner-Parker filter, it’s a 12 dB/octave multimode filter that has a distinctive sound – an acquired taste for some. The thing that makes a Steiner-Parker filter desirable is how flexible it is. It’s known to be smooth at low gain, but becomes a beast when you drive it hard.

You’ll find cutoff, resonance, Brute Factor, envelope amount, level, and LP/HP/BP control in the SP filter section. Between low-pass and band-pass, there are many stages (other than high-pass), and that’s what makes it a true multimode filter. The advantage of these in-between notches is that you can smoothly sweep from one mode to another.

The other controls are fairly self-explanatory, other than Brute Factor, which can be summarized as filter output feedback. The bi-polar envelope amount determines how much the envelope affects the filter cutoff. In other words, it sets the modulation intensity and how it will increase/decrease with filter movement.

The ladder filter, a 24 dB/octave low-pass filter, looks almost identical to the Steiner-Parker. The first visible difference is that Brute Factor has been replaced by distortion. Where the first filter has LP/HP/BP selection, the second filter has series/parallel control.

At first sight, it appears to be a pretty straightforward low-pass filter, but it comes with a vintage character. Some of the most desired vintage synths came with low-pass filters that would allow you to increase the resonance without losing the warmth at the bottom end. The PolyBrute does that very well.

Between each filter are some basic master controls for cutoff and keytrack. The ladder filter will accurately track the keyboard when set to max, but the Steiner-Parker filter not so much. There are still a few more tricks to be had from these filters, making them more than meets the eye. They are self-oscillating, and with the output from both oscillators routed to both filters, they will lock. Technically, this means you can create sounds with five distinct pitches. The pitch range comes from both oscillators, the sub-oscillator (oscillator two), and both of the filters oscillating. With the filters locked, you can modulate the cutoff of each via the noise (mixer), which is hardwired to the cutoff of filter two, and VCO 2 (mixer), which is hardwired to the Steiner-Parker cutoff.

Overall, the filters definitely offer more versatility than expected. It just takes a little bit of playing around to get the best out of them. If you are already a fan of the Steiner-Parker sound, that’s a bonus.

The modulation matrix

Arturia is no stranger to a hefty, and sometimes newbie-intimidating mod matrix. The design of the matrix has been carried over from the MatrixBrute, albeit on a smaller scale. With the PolyBrute, you get a 64-slot matrix with 16 predefined sources and 32 assignable destinations. As you look at the panel, you’ll see the predefined sources listed in a column down the left side of the matrix. Although the column only ranges from A to L (12), four of the rows have dual inputs, giving the 16 sources mentioned.

Assigning a source to a destination is straightforward; choose your destination, choose your source, and set the modulation amount by turning the amount knob. Multiple sources can be sent to a single destination; likewise, a single source can be sent to multiple destinations. The most important aspect of using multiple sources/destinations in that way is that they can each have independent amounts.

To go even further, you can use certain modulators purely to control the amounts of other modulation sources. In total, you can assign anywhere up to 64 modulation patches to a single sound. Meaning, a single patch in its A and B states can have two completely different modulation setups.

The modulation matrix is something that you need to get your hands on to understand its power fully. Reading about it will never do it any justice, and could potentially make it sound more complicated than necessary. If there is any complaint, it’s that some sources, like switches or menu parameters, take some extended menu-diving to assign. It’s not something that will cause too much grief over extended use.

Overall, the PolyBrute’s modulation matrix is extremely flexible and very powerful.

Digital effects

In a change from the MatrixBrute’s analog effects, the PolyBrute has three digital effects modules. The modules cover modulation effects, delay, and reverb.

When not building hardware synths, Arturia has quickly become masters of the plugin and soft synth world. One of their flagship soft synths is Pigments; it’s great, check it out. Many of the algorithms that drive the PolyBrute’s effects come from the Pigments software. The choice of effects suits the big poly sound of the PolyBrute perfectly.

Effects can be routed as inserts or sends, which lets you use them creatively. Insert routes the signal through all three modules in series – Modulation, Delay, and then Reverb. Send routes the signal through each module in parallel. Finally, bypass does exactly what it sounds like; it bypasses the effects, leaving a pure analog signal path from oscillators to final output.

As sends, in conjunction with modulation and morphing, effects can be added in very precise ways. It means you can add effects in bursts, in and out, rather than being limited to constantly affecting the end sound.

The overall quality of the effects is incredibly high, as to be expected from Arturia, and there are plenty of options. Effect types include chorus, various flanger types, phasing, bit-crushing, ring-modulation, and a down-sampler. Delay and reverb both have multiple types, too.

One unexpected addition to the effects section is a stereo spread knob. When the signal leaves the filters, the six voices are positioned in the stereo field in a way specified by your mode selections. Voice pan, filter pan, distribution centered, and distribution gradual can be selected individually or in combination.

There are too many variations to list, but voices can be centered, hard-panned left or right, in-between, or half left, half right. Each voice’s value/position in the stereo field is then sent to the modulation matrix as a percentage between -/+ 100%. Different selections/combinations create different percentages, and whatever mode you are in, the stereo spread knob specifies the width.

Everything you select regarding panning modes and the results those selections create can be modulated. So, if you are looking for huge spatial effects, you’ve found them in abundance.

Envelope generators and LFOs

There are three envelope generators with the PolyBrute. The first is a velocity-sensitive ADSR envelope that is hardwired to the filters’ cutoff, and it’s a source for the modulation matrix. The second ADSR envelope isn’t available as a source for the modulation matrix, and it’s hardwired to the audio amplifiers. Lastly, there is a DADSR 5-stage modulation envelope, with output only via the modulation matrix.

Like much of the PolyBrute, there is more than meets the eye with the envelopes. Different modes are available: quick, percussive, natural, shorten, and extend. Quick and percussive modes alter the curves of the decay and attack phases of each contour generator.

Natural mode shortens the attack and extends the decay and release of the selected contour generator to mimic real acoustic instruments. Shorten mode shortens all phases, while extend mode extends all phases. Furthermore, the envelopes are loopable to create a trapezoid response or complex shapes as an extra LFO.

There are three LFOs on the panel, each of which has to be routed through the modulation matrix. Each LFO can also be bipolar or unipolar. The first two LFOs are almost identical, each offering seven waveforms and rate between 0.02 Hz to 100 Hz.

LFOs one and two also offer arp, sequencer, and clock sync with three triggering modes: mono, poly, and poly retrig. Mono mode creates a single free-running LFO that applies equally to all voices. Poly mode is also free-running but offers independent LFO’s for each voice. Poly-retrig isn’t free-running; an independent LFO (per voice) becomes active when its voice is triggered. LFO two differs in that it has a fade-in function rather than phase. The fade-in parameter applies fade and delay.

The third LFO takes a different approach to waveshape selection. It doesn’t allow you to choose different waveforms freely; it automatically generates a triangle waveform. However, it does let you alter the shape in a couple of different ways. The first way is curve, that bends the waveform to make phases curves at the top or bottom, and pointed at the opposite end. The next method is called symmetry, and that lets you slew the shape from a triangle, to sawtooth, to a ramp, and anything in-between. Both of these shaping methods can be used simultaneously.

LFO three has a few unexpected but creative modes/functions. One of which causes the LFO to stop after running through just one cycle. The result is that you now have an AD contour that can be used to create a vast range of different shapes.

Another unexpected function is the xLFO1 switch that syncs the first LFOs modulation to that of LFO three when LFO three is free-running. In LFO three single-mode, LFO one becomes the trigger for LFO three. All of these modes can be combined in more ways than we can list here.

Arturia has delivered vast and complex modulation potential that you wouldn’t generally expect from this type of polysynth. It’s heading more towards what you’d expect from a modular setup and an expensive one at that.

Morphee, ribbon and motion record

When you first look at the PolyBrute, the Morphee is the one thing that jumps right out because it’s different. It wasn’t included in any of the previous Brute synths. Visually, it looks similar to something like the Touché controller from Expressive E.

The Morphee is a 3-axis (X,Y,Z) controller with three modes. Any movement with the Morphee is shown on the PolyBrute’s display screen. The first mode is matrix, which sends all Morphee interaction to the Matrix’s X, Y, and Z parameters to modulate anything you choose. Next is arp/seq mode, which uses the Morphee to randomize arpeggiator and sequencer patterns. Morph mode still controls the Z parameter of the matrix, but X and Y are used to control pitch and levels independently.

If you were to use the morph knob, you would simultaneously alter the oscillators’ pitch and timbre. Morphee allows you to morph the pitch by moving your finger up and down on the pad, or just the timbre by moving left or right. Again, it’s something that has too many possibilities to list them all; you have to get your hands on it and start exploring.

The issue some people might have is that controllers like these are often considered to be an unnecessary gimmick. I don’t personally feel that way; anything that allows you to be more hands-on has to be more naturally expressive. Once you get used to it, it becomes a very intuitive performance tool.

The ribbon controller might be missed at first glance because it’s just a groove in the rather attractive wooden strip above the keyboard. It’s quite a bit longer than a ribbon that you’d typically find beside mod/pitch wheels on other synths. It does have lots of fantastic uses, but it’s a pretty simple modulation source.

You can apply it to the filter cutoff or any other parameter via the modulation matrix. It can also control the pitch of one or all oscillators where you can use the keyboard as a guide. To do this, you have to set the mod amount (via the matrix amount wheel) to 26 (semitones), and now if you play a note, you can glide above that note to above the target note on the ribbon. The really cool thing is to use this polyphonically, smoothly sliding from one chord into the same voicing at a different pitch.

Motion record is another simple but very effective function. Basically, it records the motion of a control, like the Morphee, ribbon, or knobs, and saves it to a patch. Once you have recorded a motion, you then have the option to change the playback speed anywhere from 12.5% to 800%. Being able to change the playback speed means you can be far more precise with more difficult motions. You can use motion record to loop and modulate up to 32 parameters at once in matrix mode.

The pitch and mod wheels aren’t something to discuss in much detail, all pretty standard. Although, like all other performance tools, they can be put to many uses through the modulation matrix.

Arpeggiator and sequencer

The arpeggiator and sequencer can be hugely important parts of any synth, depending on your taste. But, for the most part, they are exactly as expected, so there’s no need to go too deep here.

The arpeggiator comes with a few different playback modes and a hold function. The playback modes cover the usual suspects, but the one that’s worth picking out is Arturia’s pattern mode. Pattern mode will play a new pattern every time you re-trigger the notes. For example, if you have a 12-step pattern built on a C major triad and re-press the notes on every step one, you’ll get a new pattern. So, it’s a good way to randomize the motion without needing to reach for knobs or buttons.

The sequencer is also pretty straightforward, and you can actually copy patterns over from the arpeggiator, which is good if you stumble onto something nice. You can set your sequence length anywhere up to 64-steps, and create some complex rhythms. You can also replace steps by overdubbing on that step while recording, or you can mute steps. So, there are lots of ways to edit your initial sequence, and it’s polyphonic, too.

The sequencer has three modulation lanes so that you can modulate up to three parameters per sequence. Modulation is just as simple as recording a sequence, enter record mode, adjust any parameter, like distortion, stop recording, and you’re done. If you aren’t happy with the results, you can delete the modulation and try something else.

Holding the arp and seq buttons down at the same time brings up the matrix arp. The matrix arp is just a clever way to arrange notes and rhythms manually. If you play a chord with an 8-step pattern, let’s say an F major7, you’ll see each step represented in the matrix. Now you can delete or move notes directly from the matrix grid rather than the keyboard.

Doing it this way often leads to patterns that you wouldn’t have played on the keys. You can also adjust the rhythm by removing steps, and of course, you can add notes on top of notes for polyphonic steps.

Interface and build quality

Any synth with a modulation matrix like the one found on the PolyBrute can look quite intimidating to a synth beginner. But, even as a beginner, it wouldn’t take long to see that Arturia is very good at maintaining an intuitive workflow. That means the panel is very functional and not overly complicated. Each area is nice and clear, from the oscillators right through the signal path.

In general, all functions are pretty easy to use and understand. The one complaint is that some functions do require a little bit of menu-diving that isn’t made easier by such a small screen. A larger screen would make things a little easier, but looking at the panel, you’d have a hard task deciding how and where to fit it in. It’s more of a necessary compromise rather than a negligent omission, so Arturia can be forgiven.

As far as the build quality goes, it’s first-class. The PolyBrute is a pretty heavy synth, put together with solid, premium materials. It won’t break unless you drop it from a height! The combination of metal and wood looks stunning, too.

Connectivity

There are two unbalanced stereo outputs, MIDI in, out, and thru, along with analog clock in and out. USB type B is available for connecting to a computer and making use of the included editor software. There are three pedal inputs, one sustain and two expression. Next to the pedal inputs, you’ll find a memory protection switch, which is handy if you don’t want an enthusiastic friend overwriting your patches. Lastly, you’ll find the headphone jack on the front, which has an independent level control.

Conclusion

Image credit: Arturia Check Price on Sweetwater

It has massive sound-shaping potential. Relatively simple to use. Morphee, ribbon, and other performance tools. Versatile and flexible. Has real character in its sound. Incredibly flexible modulation matrix. Polyphonic sequencer. Small screen. Some menu-diving. 6-voices might limit some players.

Arturia hasn’t been shy about praises the PolyBrute as the new flagship of their Brute range. In my opinion, they are right to speak so highly of their newest addition. It’s hard to find a similar polysynth that offers the same flexibility as the PolyBrute.

In its most basic form, the oscillators sound great. Add to that some lovely filters, especially if you are already a fan of the Steiner-Parker filter that Arturia uses so often. Modulation options are off the charts with this synth; it really does push the boat out there. In that sense, despite being somewhat expensive, you get far more than you pay for in unexpected features/functions.

The thing that most distinctly sets the PolyBrute apart from other polys is the performance tools. Starting with morph mode, which is much more than just a typical cross-fader. Going onto the Morphee that undoubtedly lets you play in ways that you simply couldn’t do without it. To address any complaints, there isn’t any easy way around the small screen.

As for being limited to 6-voices, more voices means more cost, and maybe Arturia could have offered a higher-priced version with more polyphony. The PolyBrute is a force to be reckoned with; it’s a beast.