Review: Arturia MatrixBrute

Could this make modular synths obsolete?
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Broadly speaking, I consider newer synths superior to vintage synths. I still love the old classics, but keeping them maintained is a pain, and replacement parts are getting scarce. Compared to more recent instruments, many vintage models are also lacking in worthwhile features like multiple filter types, sophisticated modulation routing, onboard effects, and native computer connectivity.

The MatrixBrute, from Grenoble-based music software and hardware maker Arturia, aptly demonstrates the advantages of modern technology. It combines those features with a 64-step sequencer, astounding flexibility, and unparalleled real-time control. Although it’s monophonic, the MatrixBrute also offers 3-note paraphonic and split modes.

Working with the MatrixBrute is a lot like using a modular synthesizer in that you can connect almost any function to almost any other function. Instead of patch cords, it has a matrix similar to the grids seen on EMS’s VCS3 and Synthi A in the 1970s, but with buttons in the place of patch pins. It also lacks the main display that most synths require for user programming. But it doesn’t need one, because virtually all parameters are directly accessible from the front panel without diving into menus. In fact, the MatrixBrute has no menus.


The 44-pound MatrixBrute has a 49-note, unweighted keyboard that transmits MIDI velocity and aftertouch. Its rugged steel-and-aluminum body is trimmed with dark wood and Tolex on the sides. Its control panel flips up on hinges to allow positioning in one of three angles, or you can leave it lying flat. Flipped down, it locks securely in place.

Fig. 1. The MatrixBrute is a one-of-a-kind synthesizer combining analog sound and digital control. “Unfortunately, no one can be told what the Matrix is. You have to see it for yourself.” — Morpheus

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The multifunction matrix dominates the front panel and gives the MatrixBrute its name (see Figure 1). A tightly packed 16 x 16 grid of 256 rubbery, backlit, translucent white buttons, it shares the front panel with assorted knobs, envelope sliders, and buttons paired with indicator LEDs. The matrix serves three obvious functions, determined by buttons labeled Preset, Seq, and Mod.

A 3-character LED display indicates the current preset location, and a 4-character display indicates tempo. The 1.75 x 0.875-inch monochrome E Ink display, which is not backlit and retains its contents even when powered down, lists the current preset’s name and assignments for four user-definable modulation destinations in crisp type that’s slightly smaller than the words you’re reading now.

Almost every control, except the matrix buttons, is dedicated to a single function. Controls are organized in sections such as VCOs, VCFs, and effects. The front panel offers enough visual feedback so that you can focus on any detail of the whole signal flow at a glance. A Panel button makes all the controls live, disregarding the selected preset so you can program the MatrixBrute as if it had no memory. All controls transmit MIDI data, and all parameters respond to MIDI messages.

Conveniently located between the keyboard and the pitch bend and modulation wheels are several performance controls for enhancing real-time expressivity. These include knobs and buttons for glide, octave shift, note priority, and legato mode, as well as four smooth and assignable rotary encoders for controlling macros. On the front left, below the performance controls, is a ¼-inch stereo headphone output, right where it should be.

Fig. 2. In addition to master outputs and a TRS insert, the rear panel has a mono input with gate detection, DIN 24 sync, and two dozen minijacks for interfacing modular synths and other external gear.

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Along with two unbalanced master outputs and a TRS insert, the back panel has a monophonic input with a switch to enable gate detection, allowing the synth to trigger envelopes from external instruments or click tracks. You can route the input to an envelope follower, which makes the Matrix-Brute a monster for processing guitar, for example. Twenty-four 3.5mm jacks serve as CV ins and outs connected to the VCOs, VCFs, VCA, and one LFO, as well as gate ins and outs connected to the envelopes. These allow interfacing with Eurorack modules and other external devices. A DIN 24 jack connects to compatible gear, too (see Figure 2).

MIDI connections comprise USB and In, Out, and Thru DIN jacks, alongside connections for a sustain switch and two expression pedals. The internal power supply has an IEC connector and works with 100 to 240VAC sources.


The MatrixBrute has three analog oscillators and a noise generator. VCO 1 and VCO 2 are identical, generating sawtooth, pulse, and triangle waveforms you can mix using the waveform level knobs. Each waveform has one knob that modifies its spectrum. The Ultrasaw knob thickens the sawtooth by adding two slightly out-of-phase copies. Pulse Width varies the duty cycle from square wave to zero output. The Metalizer knob adds overtones to the triangle wave output. VCOs 1 and 2 each have a sub-oscillator that plays a fixed octave lower and is continuously variable from sine to a dull square. The third oscillator, VCO 3–LFO 3, functions as both a sound source and a modulation source.

The noise generator produces more colors than you would expect. In addition to the usual white and pink, it generates red noise, which uses extreme high-cut filtering to suppress high frequencies entirely, and blue noise, which uses low-cut filtering to suppress lower frequencies.

The MatrixBrute has two filters, VCF1 Steiner and VCF2 Ladder. In the 1970s, Nyle Steiner, who developed the Steiner-Parker electronic valve and wind instruments, designed a filter Arturia later adopted for the Brute series. VCF1 can sound more raw and raspy than most typical synth filters. In contrast, VCF2 sounds smooth, fat, and practically identical to Bob Moog’s much-loved ladder filter. Their user parameters, which include Drive and Brute Factor distortion, are identical except that VCF1 has a notch response in addition to lowpass, highpass, and bandpass. You can switch either filter from a 12-to 24dB-per-octave slope. A prominent rotary encoder labeled Master Cutoff offsets the two filter frequencies equally.

In the Mixer section, the MatrixBrute’s audio path routes all sound sources through either or both filters. Selecting both lets you route them in series or parallel.

In the Audio Mod section below the VCOs, you can route oscillators and noise to modulate the frequency of the other oscillators and either filter. VCO 1 can modulate VCO 2, and VCO 3 can modulate VCO 1 or 2. VCO 3 can modulate either filter, and the noise generator can modulate either VCO 1 or VCF 1. Any combination produces a broad range of harmonically complex timbres.

In the Voice section, you can choose Monophonic, Paraphonic, or Duo-Split modes. When playing paraphonically, the MatrixBrute can produce three tones simultaneously, with each VCO generating a separate tone while sharing the VCA, VCFs, and envelopes. Selecting Duo-Split mode enables a second, hidden VCA to play separately articulated voices. You can play two timbres simultaneously on the left and right halves of the keyboard, or one on the keyboard and the other with the sequencer. One side of the split uses the Steiner filter controlled by Envelope 1, and the other uses the ladder filter controlled by Envelope 3. How you route the VCOs to the filters determines which side is duophonic.

The MatrixBrute is the first monosynth I’ve seen with this kind of split capability. I found that pitch bend and octave shift affect only the right half, and glide affects only the left half, whereas the mod wheel affects both. You can, however, transpose the left half by holding the Mode button as you shift the octave. You can’t load two different presets to create a duo split, though you can create your own preset that incorporates one preset from memory and another timbre you create manually.


Because the three ADSR envelope generators have sliders, you can see their settings instantly, and that’s always helpful. Envelopes 1 and 2 are hardwired to the filter and amplifier but can modulate any destination. Each has an additional slider that determines keyboard velocity’s effect. Envelope 3 has no fixed assignment and has a Delay slider that postpones the attack for up to 10 seconds.

You can sync either of the two LFOs with the sequencer or an external clock. The LFOs are almost identical, but where a knob on LFO 1 determines its initial phase, a knob on LFO 2 delays its onset. Each LFO offers seven waveforms, including sample-and-hold and noise. They can either loop continuously, wait until they receive a gate signal to begin their cycles, or cycle through just once and stop, like an envelope.

In Modulation mode, the matrix organizes mod sources in 16 alphabetized rows and mod destinations in 16 numbered columns. To route modulators, you first press the Mod button, then press the button that aligns with the desired modulator and destination, and then adjust the range with the Mod Amount encoder. If you want to modulate the VCF1’s cutoff with keyboard velocity, for example, press the button where row K (Velocity) intersects column 9 (Steiner Cutoff ), and then dial in the maximum modulation depth. Because there are more possible mod destinations than columns, however, you can assign any destinations you choose to the last four columns, and your assignments will be shown in the E Ink display.


The Analog Effects section is based on a bucket-brigade device (BBD), a delay line on an analog signal-processing chip. The effects comprise stereo and mono delay, chorus, flanger, and reverb. Two buttons change effects type and enable sync. All the effects share three knobs—Delay Time, Regeneration, and Wet/Dry mix—and the function of the other two, Tone/Rate and Width/Depth, depends on which effect is selected.

Analog reverb has an unusual but toothsome character, and varying its parameters with modulators yields even more unique timbres. Things can get especially interesting when you modulate delay time with an LFO, envelope, or mod wheel. I like the chorus more than most, particularly its ability to impart width. The delays have a maximum half-second delay time, and the stereo delay has two taps and uses the Width/Depth knob to introduce a stereo ping-pong effect. You can’t independently control delay time for the two taps, though, which limits its versatility. But the biggest downside is that with only a single BBD, your preset can apply only one effects type at a time.


Fig. 3. In combination with the 16x16 matrix, the Sequencer section furnishes all the controls you’ll need to record, edit, and control sequences and arpeggios.

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The MatrixBrute stores 256 step sequences called Patterns, which can be linked to presets or stored on their own. Unlike synths that make you scroll through menus, the MatrixBrute accesses all sequencer functions using the grid’s 256 buttons and the Sequencer section’s 24 buttons and 3 knobs (see Figure 3).

The transport controls are in the Sequencer section, which also handles parameters such as pattern length, tempo, swing, gate time, note values, and clock divisions, either as you’re recording or during playback. I was thrilled to discover the sequencer transmits MIDI data, which means it can play external instruments and you can record patterns into your DAW tracks.

Engaging Sequencer mode divides the matrix buttons into four groups of four rows, giving you four buttons per step. Each group has 16 steps for a maximum 64 steps in a pattern. The four buttons in each step control four parameters. The Step button illuminates to indicate that a note will play; if it’s dark, it indicates a rest. The Slide button turns glide on between one step and the next, facilitating the type of slurs that made the Roland TB-303 famous. An illuminated Accent button indicates a higher velocity value for a step, either enabled by pressing it or recorded in real time. Mod enables modulation for the selected step once you’ve set that up in the modulation matrix. You can enable or disable any of these buttons while you’re programming a pattern or on-the-fly during a performance.

You use the keyboard to record patterns one step at a time, giving each step equal duration, or you can record quantized patterns in real time and even punch in when needed. Enter rests by pressing the Sequencer section’s Tap button. When you finish recording, you can change a note’s duration or tie notes together by pressing two or more Step buttons at the same time. Change the pitch of any step by first pressing Record while the transport is idle, then selecting a step, and then playing a new note. You can also use the keyboard to transpose the entire pattern during playback.

The Sequencer section also controls parameters for the arpeggiator. The arpeggiator has four normal play modes—forward, reverse, random, and alternating forward and reverse. Its real power, however, lies in Matrix Arpeggiator mode. When you press the Sequencer and Arpeggiator buttons simultaneously, the upper group of four rows becomes a 16-step sequencer, and the three groups below determine which note will sound when you play a 4-note chord. Each of the three groups may be assigned to a different octave, and you can transpose any step up or down a semitone.

Although I was happy with the sequencer’s versatility and ease of use, it didn’t meet all my assumptions. When I heard you could program the sequencer from the matrix, I wanted to press buttons in the grid to enter notes the way you can with, say, Ableton Push’s note mode, Yamaha’s Tenori-On, or Fugue Machine on the iPad. I hope this feature will be possible in a future update.

In Preset mode, predictably enough, each button in the grid loads one of the 256 internal presets. When you switch from one preset to another, the previous preset cuts off immediately, and you’ll notice a pause (less than a second) before pressing a key triggers a sound. That delay can be a problem in some situations.

Fig. 4. Arturia’s MIDI Control Center lets you access the MatrixBrute’s global parameters and store thousands of presets and patterns.

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The factory presets supply a veritable menagerie of expertly crafted timbres that sound terrific, though none of them takes full advantage of everything the MatrixBrute can do. When you install Arturia’s free MIDI Control Center on your computer, you’re no longer limited to 256 presets and 256 patterns. The software can serve as a patch librarian, allowing your computer to store an unlimited number of presets and patterns (see Figure 4). You can drag and drop them between your computer and the MatrixBrute, arrange and organize them into projects onscreen, and tag them with keywords. You’ll also need MIDI Control Center to configure global parameters such as MIDI channels, clock source, velocity curves, and so on, and to update the MatrixBrute’s firmware.

As much as I’ve come to admire the Matrix-Brute’s design, it does have flaws. The most serious is that audio signals can bleed between circuits. With the filter open and all mixer inputs disabled, for example, I noticed a faint periodic sputtering, like gentle helicopter blades. The sputtering took on pitch when I raised VCO 3’s frequency, and I traced it to VCO 3 bleeding through the Steiner filter.

A similar problem I couldn’t track down completely was a sort of rhythmic beat bleeding through from LFO 2 whenever I turned any effects to fully wet—again, regardless of whether the filters were switched off. When I asked Arturia about the problem, I was told the cause was packing so many components into such a compact space, making occasional bleeding between circuit boards inevitable.

The pitch-bend and mod wheels feel more lightweight than on any of my other synths, but my bigger concern is the gap in the metal opening at the top and bottom of their throw. When you push a wheel to its extreme, you can feel the precision-cut edge of the opening.

Overall, though, I’m quite pleased with the MatrixBrute’s build quality. The knobs, sliders, and buttons are all good, and some are excellent. The construction is solid, and I wouldn’t hesitate to take this instrument out on the road. Unlike some digitally controlled synths, the MatrixBrute generates control signals with such fine resolution that turning a knob or modulating a signal doesn’t produce the slightest trace of zipper noise.


Despite its minor flaws, I’ve fallen for the Matrix-Brute, and I’ve fallen hard. It does almost anything I’d want an analog monosynth to do, with few qualifiers. Given current technology, it comes as close as possible to a Eurorack system without patch cords. Unlike a modular synth, though, it memorizes and recalls every connection, every preset, and every sequence. Sure, some modules do plenty of things the MatrixBrute can’t, like ring modulation or generating exotic wavetables, but you can overcome such limitations by connecting its insert jack to outboard effects and its CV and gate jacks to modular gear.

Without a doubt, the MatrixBrute is an instrument that has won my respect and admiration. This isn’t just a lot of synth for the money; it’s a lot of synth, period. Arturia has made me a devoted fan.

Terrific sound. Unbeatable modulation routing. Well-organized panel layout. Paraphonic and split modes. Expressive performance controls. Onboard sequencer transmits MIDI data. Ample CV and gate connections. Free computer-based patch librarian software.

Slight pop and pause when you change presets. Circuits sometimes bleed audio signals. Unbalanced outputs. Computer software needed to edit global parameters. Small alphanumeric display.


Writer, synthesist, and EM editor-at-large Geary Yelton spends most of the year in Asheville, North Carolina.