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This Month’s Module: Going Off the Grid with Shakmat Modular’s Four Bricks Rook



With Eurorack modules like Four Bricks Rook, you don’t have to choose between music that sounds mechanical and music that sounds out of control.

The music you make on a modular synth is a collaboration between you and your modules. The stereotype is that modern modular music is either beat-driven or completely random, without much human feel. Like many stereotypes, that perception may contain a grain of truth. Many sequencers, pattern generators, and related modules are designed either to play notes and triggers on a master timing grid or to create random bursts of triggers that may or may not be connected to that grid. Very few are designed to record your own musical events in “free time” or patterns that aren’t quantized to a musical subdivision such as sixteenth notes.

Take rhythm pattern generation modules, which are a particular interest of mine. As Kim Bjørn and I illustrated on pages 298-303 of the modular synthesis book Patch & Tweak, such modules take diverse approaches to how they create their patterns.

Some—such as the Mutable Instruments Grids, Qu-Bit Electronix Rhythm, Ladik Composer G, and Noise Engineering Zularic Repetitor—supply tables of preprogrammed master rhythmic patterns that you choose between. 

Some—such as the Erica Synths Drum Sequencer, Tiptop Audio Circadian Rhythms, and WMD Metron—allow you to set points on a grid indicating when you want a trigger to be sent. 

Numerous modules employ rhythm generation algorithms, such as Euclidean rhythms.’s Euclidean Circles is the most common example. Many modules employ this and other algorithmic techniques.

Others—including the Malekko Heavy Industry Varigate 8+ and the Vermona random RHYTHM—allow you to set the probability and density of trigger events they generate. Indeed, most pattern generation modules have a random variation function.

And many modules—including random-voltage sources, such as the Wogglebug—can create either completely random trigger events or send out bursts of triggers in response to receiving a single gate input.

But what if you just want to tap in your own note patterns in real time, rather than choose or laboriously program a predetermined pattern? What if you don’t want those individual events to be autocorrected to a regimented grid? Then your choices are far fewer. Perhaps the best example of a module that allows you to start breaking the grid and play back what you intended—timing variations and all—is Shakmat Modular’s Four Bricks Rook.

Using Four Bricks Rook

When you first power it up, Four Bricks Rook (4BR for short) acts as a trigger-pad module, with four pads and four output channels. You can connect those triggers to any sources; the patterns that come with 4BR assume you’ve connected kick, snare, hi-hat, and a synth stab, respectively. The Menu display and control in the upper left defaults to setting the duration of those triggers; the maximum length is one full incoming clock cycle. (Note that when using the Menu knob, you often have to sweep it past its current value before it picks up your changes. Look for the decimal point in the display: when it appears, it has recognized your change; before then, changes will be ignored.)

For 4BR to play back anything that’s been previously recorded, it needs to receive a clock pulse. It assumes a clock based on sixteenth notes, as do many Eurorack devices with clock inputs. 4BR then internally multiplies that rate by 12, creating a 48 ppqn (pulse per quarter note) internal grid—twice the resolution of MIDI clocks and most DIN-sync devices.

Given that, 4BR is not truly a “free time” device, as it actually quantizes your taps to a high-resolution internal grid. But at high-enough tempos, the time between grid steps quickly becomes smaller than the precedence effect, in which two separate events merge into one. You can also send it a faster clock—such as thirty-second notes—for even finer resolution.

The left display shows an output pattern (the magenta trace) being quantized to the incoming clock (the green trace). The right display shows playing back the same pattern “unquantized” and based on the internal high-resolution grid.

Pattern Recognition

To record your own patterns, first set the Length using the central knob. This determines the number of incoming clock pulses that will constitute your pattern; if you choose, you can play back smaller segments of it later. Then press the REC button in the lower left, verify that the red LED below it is illuminated, and start tapping out your patterns. Once 4BR has looped through the buffer set by that Length control, it will overdub any new taps on top of what you’ve already entered. If you want to keep what you’ve done, press REC again. If you feel you’ve made a mess of things, hold down the Erase button (second from left), and then press the pad for the pattern you want erased. 

If you feel you’ve gone too far off the grid (or have lousy timing, as I do), hold down the Quantize button (second from right), and press the pad corresponding to the channel you want autocorrected to the coarser grid set by the incoming clock. This is just a temporary function; holding Quantize while pressing the same pad again will take you off the incoming clock grid and place you back on the internal 12x resolution grid to restore your original feel.

You can save your new pattern into any one of 128 memory positions (16 Slots x 8 Tables). These positions are preloaded with ten Slots of patterns created by Shakmat and guest artists (including Richard Devine, Ucture, and others), plus six Slots of utility patterns. You can overwrite any of them with your own patterns or recall the factory presets later if you wish.

To load a pattern Slot from memory, first you must be in Pattern mode, enabled by holding Function and pressing the second pad. Hold down the Function key (far right) and press REC/LD PTRN, dial up the desired Slot using the Menu knob, and press REC/LD PTRN again. Each Slot contains eight Tables, which can be selected by both a dedicated Table knob and external control voltage.

Interactive Performance

Four Bricks Rook goes beyond being a simple pattern recorder and player by allowing you to interact with patterns. It contains two memory buffers that you can switch between. In Pattern mode, each pad toggles between those two buffers for a particular channel. Fill mode (hold FNCT and press the third pad) allows you to momentarily play the other buffer. Holding FNCT and pressing the fourth pad enters Mute mode, in which you can turn individual channels on and off. Even more impressive is that the same REC button also records pattern toggles, fills, and mutes, as well as Table changes. This description only scratches the surface of what 4BR can do; for more detail, consult its manual or online videos.

A typical modular performance usually features the musician controlling more than playing, often toggling preprogrammed sections on and off. It’s nice to see more modules appear that make modular music more interactive and performance-oriented, not to mention giving you the option to play your own patterns with your own timing, if you wish.


Price: $320

Synth and Software would like to thank longtime modular user and former synth designer Chris Meyer for his contribution. Chris is the force behind Learning Modular, where he teaches others how to master modular synthesis. 

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