Expert Sleepers Disting Mk4 Review – The Swiss Army Knife Of The Eurorack World

Disting Mk4 is the recently-released 4HP module from British company Expert-Sleepers. It’s a 69-in-1 multifunction Eurorack module. It covers a huge range of audio and CV processing, in a small 4HP module.

The entire ExpertSleepers module line seems to be in the process of visual refreshment, with the newer module versions having led rings around the input/output sockets.

Not only is this very aesthetically pleasing; it’s also very useful, showing both the presence of signal, and also the polarity of the signal, red and blue for positive and negative.

In the case of the Disting MK4, the old led menu has also been replaced with a dot matrix menu, giving a more informative view when flicking through settings.

The Disting MK4 consists of two input sockets, two output sockets, a CV input, a couple of encoders and the aforementioned menu.

There’s also a microSD card slot, for various functions which I’ll come to later. The ADC, DAC, and processing sample rate are all great for ensuring good audio signal coming out the other side.

The two rotary encoders (also both push buttons) achieve different functions – ‘S’ at the top of the box works all the top-level functions; the algorithm menu, settings, help and calibration. The Z encoder is more involved with the parameters of the particular function you’ve selected.

With the latest firmware update, the menu system has been simplified, especially when selecting an algorithm. It’s now a list, whereas before it was a bank/list selection process which was a little confusing in terms of knob presses and knob turns. Now you can push and hold the ’s’ knob, and turn it to the algorithm you want. Done. Much better.

The settings provides housekeeping such as display brightness, turning on auto-store; which basically saves parameters as you use them, (the disadvantage being a slight glitch as it saves).

The other setting is a recall enable, which uses a protocol only used by a small handful of modules to recall user settings such as presets.

Calibrate does what it says on the tin. Using a reliable 3V reference from elsewhere in your system, pressing the calibrate button will cause the Module to calibrate itself. This should be unnecessary in most circumstances as it’s calibrated from the factory. If you accidentally start calibration, pressing the ‘Z’ knob cancels it.

It’s not that straight forward a process, so proceed with caution, and as the manual clearly spells out at the top of the calibration section, ‘If in Doubt, ASK!’

All the Algorithms

This is the impressive thing about Expert Sleepers – the upkeep by the expert sleepers team (which if I’m not mistaken is a team of one: the creator Andrew Ostler) is very active.

The first Disting had 16 algorithms. As of this writing there are 62 69 of them! Even in the few weeks I’ve had the module for review, the firmware has been updated twice three times!! with extra algorithms.

The algorithms  cover a HUGE diversity of utilities, audio and CV/gate processing and triggering, plus audio and MIDI file playback.
I won’t be able to write about all of them in this review, as it would take too much of your time. But I recommend checking the videos that have been recorded for each algorithm, which cover all the technical elements.

The algorithm description list (alongside the useful manual) is online, with concise descriptions of the functionality of each input, output and knob.

It’s just unbelievable how much is packed into this little module. It’s impossible to remember all the functionality of every algorithm; this is where the help function in the menu comes in.

If you install a micro SD card (not included) and add some help text files kindly provided by Expert Sleepers, once you select ‘help’ in the menu – the Disting will display specific information to that algorithm, describing it, and reminding you of the control parameters specific to that algorithm. Here’s a vid showing it in action.

The Disting covers many of the elements needed in the audio synthesis chain – from provision of the sound source in various forms (VCO, wavetable, audio file playback), a myriad of sound modulation options – envelopes, filters, LFO’s, S+H, quantize, adder, multiplier, and many different FX – such as phaser, delays of various types, resonator, wave shaper, bit crusher; I can go on.

Of course, being modular – a lot of these algorithms operate in both the audio rate, and control worlds.


On top of all of this, there are a bunch of really useful utilities. Pitch, Freq reference and a tuner are all extremely useful – one particular oscillator module I have is fairly temperamental tuning-wise – so having these simple utilities to check tuning is fantastic. One of the many cherries on top of a substantial cake.

There’s also voltage rate conversion to help those lucky people with Buchla gear get the 1.2v octave down to 1v oct and vice versa.

The Disting4 also has a pair of MIDI ports on the board: 1 in 1 out. You can access these by purchasing an additional MIDI module from expert sleepers (out soon) or you can diy it – as the creator encourages an ethos of hacking, and has given enough information for you to create your own breakout MIDI box, if you so wish.

Alongside the specific algorithms for MIDI, there is common MIDI control for all. You can control each parameter with the first 5 CC numbers. The specific algorithms enable MIDI files saved on the SD card to be converted to CV and played – either clocked or free. They also enable MIDI clock and note conversion from MIDI to CV and vice versa.

Instead of listing all the different elements for each algorithm and bore you to death, I’m going to spend a bit of time with some of my favourite algorithms (at the moment), so you can see how using the module works in principle. (it’s the same for every algorithm)

Shift register quantized random CV’s

Selecting F6 gets you to this algorithm, which generates random CV with the rotating shift register method

Output A is the random pattern of CVs. Output B is a trigger output, triggering every clock beat.

The X input is for clock. Every beat, the shift register rotates to a new selection of CV outputs. Turning the ‘Z’ knob allows for control over the chance element – the most (totally) random setting is at 50% – the furthest clockwise and anti-clockwise effectively locks the pattern, disabling it from change. Experimenting with this allows for how fast the pattern changes. Input Y allows CV control of this change.

Parameter change

Every Algorithm has parameters that can be altered. You access them by pushing the Z knob as a button. This cycles through the parameters you can control. They’re different for every algorithm and can be referenced either with the online manual, or with the help text files in the menu. Once you’ve cycled through to the parameter you want, by clicking the z knob, you alter the parameter by turning the ’S’ knob.

In the case of this algorithm, there are 4 parameters you can change. Parameter 0 affects the direction of the rotation of the registers. The more I played with this function, the more I could hear a slight differentiation of the sound patterns.

Parameter 1 sets the length of the shift register, and so the length of the repeating pattern. This can change from 1 note, to 16.

This algorithm is quantized – which means you can control your note choice to diatonic harmony if you wish. Parameter 2 allows you to choose from 15 different harmonic selections, ranging from chromatic, pentatonic major and minor scales, to triads (the basis of chords) with selections adding notes to the basic triad.

Parameter 3 is an attenuator – which alters the amount of CV incoming, which in this case affects the note range of the CV output. So with greater attenuation, the octave range of the random notes shrinks.

So by messing with the parameters of this algorithm, you can create very musical shifting patterns, not too dissimilar to an arpeggiator. You don’t have choice over the exact notes you can choose, but you can give some fairly tight boundaries (key, chord/scale selection, octave range) which gives you very controlled randomness. I particularly liked playing with the chance control (Z knob) varying the amount and time of change of the sequence. I loved this algorithm for the way it played a nice balance between control and chance. You could create a lush sequence in a key/freq range you want, but the element of chance keeps it interesting to the ear.

I jammed for a while with the random quantized CV algorithm, through a Pittsburgh Modular Lifeforms SV-1 and a delay. Through the jam, I mess with the scale, attenuation, pattern length and direction. I have the chance change element controlled by a slow moving LFO.

Wavetable VCO

Another cool element of the Disting is the audio file playback. This comes in several forms. You can use it as a straight sample trigger – with different algorithms to CV control the speed, end point, and transposition of the sample.

The manual is very clear and helpful regarding the recording, format and naming of the audio files.

The VCO’s all sound great, and are extremely useful if you want that extra oscillator. My favorite, however, is the wavetable VCO. You can add up to 62 waveforms to the SD card, providing an unlimited supply of different waves to oscillate. X input is V/Oct pitch, with fine tuning provided on the Z knob. The Y input controls the entire table lookup. There are two parameters for this algorithm – the first controls the selection from the list of waves. The second controls the octave choice for the wave.
Output A has the wavetable output. Output B has a square wave pitched an octave below the wavetable, to thicken up the sound.

I love using a wavetable for getting sounds that contrast and complement the usual analog crowd. This algorithm is great for getting even more timbres in your modular music. And I particularly love the fact that you can control the movement in the wavetable lookup – morphing or flicking between timbres with whatever control mod you fancy. Brilliant.

Dual Euclidean patterns:

Euclidean patterns are great ways of inspiring rhythmic creativity, and can be very useful for digging into your sounds; creating unique, polyrhythmic patterns. The dual pattern algorithm creates two different patterns. You can choose the number of steps for the patterns, select the number of pulses (hits), pattern 1 being parameter 1, pattern 2 pulses are on the z knob, so you can arrange them separately. Rotation is essentially a beat shift – moving both patterns forward and backward through the beats. Parameter 3 sets the pulse length in time. Default is 10ms, which is fine for most rhythmic material, but if you want a longer pulse, the length is cut to fractions of the clock input, parameter ranged from 1 – 31.


For the price, the size of the module, and the excellent (super quick) support from the one man Expert Sleepers team (does this guy actually sleep?), I would say this Disting Mk4 is a no-brainer: an essential piece to add to your Eurorack.

It’s the swiss army knife of Eurorack: that ridiculous one that’s wider than it is long, containing more useful elements than you could imagine would fit in its diminutive size.

The only element I could think of to add to it would be to be able to select CV control of any of the algorithm parameters. That’s a minor issue though, considering everything you already get within this tiny box, and I don’t want to appear greedy. Regardless; the speed at which mr Ostler pumps out firmware updates keeps me very excited for all the possibilities to come. Highly recommend you get this module.

The Disting MK4 retails for £139, and is available from most retailers that stock Eurorack modules. For more info, see here.

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Expert Sleepers Disting Mk4 Review – The Swiss Army Knife Of The Eurorack World

by Andy Dollerson time to read: 8 min