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Intellijel Plonk

Eurorack Module By Paul Nagle
Published May 2018

The Intellijel Plonk uses physical modelling to generate many voices of a typical drum machine, but it’s equally suited to creating strikes and hits with no real-world equivalent. And unlike many percussion modules, Plonk’s remit stretches to pitched instruments too, such as plucked strings, marimbas, bells and more.

Size: 12HP. Current: +12V = 170mA, -12V = 6mA.Size: 12HP. Current: +12V = 170mA, -12V = 6mA.In order for one voice to ring out when another is triggered, Plonk has been given two notes of ‘polyphony’. However, as there’s only a single set of CV/Gate jacks, there’s no way to hit two different notes simultaneously. Even so, it’s pretty useful to avoid the abrupt choking of cymbal decays, guitar twangs and the other shortcomings of monophonic voicing. If you play legato-fashion, the first note slides into the next — a behaviour you’ll probably appreciate more on a bass guitar patch than, say, a vibraphone. A gate delay and per-sound pitch locking is scheduled for a future firmware update, to ensure the pitch slide is optional.

This is a module packed with tweakable parameters, its menu system navigated by a single pushable encoder. For instant gratification, you’ll be glad that most of the 128 patch slots are already filled with credible examples of kicks, snares, chimes, guitars and a smattering of exotic thwacks and bangs. All can be tailored, fine-tuned and overwritten once you get up to speed. The module also features a USB MIDI interface and a simple SysEx transfer procedure, so you can offload patches and pass them around to show off your programming chops.

One thing you’ll notice is that, when any patch is loaded, it immediately conforms to the live knob settings of the module. To me this seems the best way to minimise confusion and have Plonk conform, as far as possible, to WYSIWYG. The panel sports controls for two essential parameters, Pitch and Decay, along with two further knobs, X and Y, which are bi-polar and assignable to chosen functions in each patch. Finally, Mod is another free modulation routing that, although it lacks a dedicated panel control, has an attenuverter and a button to quickly view or switch its assignment. Let’s face it, if every menu item had its own CV input, Plonk would be a very large module indeed — so per-patch assignments make sense.

The physical modelling implementation begins with an exciter, which can either be a mallet, noise or any blend of the two. The noise can be shaped with an amplitude envelope and processed by low-pass and high-pass filters. (Placing both in series gives a band-pass mode.) With just a single encoder to navigate and update values, it’s fortunate that the accessible parameters are those that make the greatest impact. Thus, you can adjust the mallet’s stiffness, the density of the noise source, the cutoff and resonance of the two filters — and assign the most important of these for live knob (and CV) control. Since pitched percussion is a vital Plonk element, the envelope can switch from AR to an AHR type, with the hold phase remaining while the gate is high.

Next along the processing chain, the exciter is fed into a resonator. For this, six mathematically modelled objects are presented: string, beam, marimba, drumhead, membrane and plate. Each has its own sonic characteristics that can be further adjusted in the Object menu. Then it’s just a matter of trying each in turn, maybe starting with plucked or bowed string instruments before moving on to the hard stuff: woodblocks, claves and xylophones. I found it interesting to discover just how many different drums could be constructed from the circular membrane — snares, kicks, tablas, pot drums and toms all poured forth with ease. Naturally, the circular plate is a worthy source of cymbals, hi-hats and gongs but, since all objects have some degree of overlap, it’s also capable of regular percussion such as congas, finger clicks, castanets and even cowbell.

Increasing the inharmonicity of any object enhances the metallic or bell-like qualities, while decreasing the same parameter tends to make the sound more woody, hollow or breathy, depending on the noise/mallet mix of the exciter. With the position parameter, you can simulate striking each object in different ways. This, along with the tone controls, is enough to produce some surprisingly acoustic-sounding hits. Independent choking can be applied to the exciter, resonator or both.

One of my favourite Plonk features is the switching of patches by incoming CV. In this way you can serve up kick/snare combinations, dynamic guitar/marimba switches or any pairing that takes your fancy. If you see the word ‘kit’ in a preset, it means that incoming CV at the Mod input has already been mapped to patch switching. And, in yet another use of the Mod input, a destination of ‘randomise’ will scramble every exciter and object parameter (except polyphony) on each hit. If you enjoy this kind of wild unpredictability, you can generate random patches with a press of the encoder in the same menu — and store the good ones for later. Continuing with the theme of unexpected delights, a Mod destination of ‘morph’ employs CV to morph between the patch’s own values and those of a different patch.

Having played with Plonk for a while, I (almost) stopped thinking about cheap wine and pondered, instead, the number of roles such a compact and versatile module could fill. I’m glad the physical modelling of drums and melodic instruments was included and I also appreciated the philosophy behind patch memories that honour physical controls. When you factor in the ease of patch switching, the dynamic control and the morph/randomisation functionality, it’s clear that Intellijel have a hit on their hands.