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Oto Machines Biscuit

8-bit Effects Processor
By Paul Nagle

OTO Machines Biscuit

The Biscuit is as crunchy an 8‑bit processor as anyone could wish for, but there's much more to it than that...

The Biscuit is the first product from French company Oto Machines. At a time when 24‑bit home recording is commonplace, Oto challenge our perception of how audio should be treated. As an 8‑bit processor — or bit cruncher — the Biscuit features a selection of 8‑bit effects, their distortion and aliasing tamed (to an extent) by a multi-mode analogue filter. This stereo device has a no-nonsense user interface and aims to be an appetising casse‑croûte for dance producers, DJs and lo‑fi seekers everywhere.


My schoolboy French (I keep him in the cellar) reminds me that the correct pronunciation is 'biskwee'. Fortunately that, plus a few non‑obvious button combinations, is about as taxing as it gets. The Biscuit is entirely menu‑free, and you can discover all its options in an hour or so. I'm not implying any shortcomings or omissions, simply that the Biscuit is très efficace in both design and function.

While this isn't the kind of black box to take a 30,000 foot drop (those are usually orange, anyway), the quality is evident in the smooth rotation of knobs and the sturdiness of the metal case. Weighing in at around 580g and a tad smaller than an Eventide stomp box, it is one of a growing army of novel‑sized gadgets contending for space on studio desks and shelves — or nestling amongst CDs or laptop peripherals in a DJ's rucksack.

Anyone intending to rig up a Biscuit to a DJ mixer should note that all audio connectors are on quarter‑inch jacks — two in and two out. And as it speaks MIDI better than I parle Francais, there are the relevant In and Out sockets, but no Thru. Perhaps in an attempt to improve the entente cordiale, the rear-socket text is printed upside down, which is ideal when leaning over to connect stuff.

It's when you connect the 9V AC adaptor and press the power switch that this unassuming little box is transformed. Even before any audio escapes, bright colours spill from beneath rubber backlit buttons. The Filter button is green, orange or yellow according to its mode, and the centrally positioned 'Brain' emits a soothing blue when aroused. In contrast, Bypass is backlit in green, turning an autumnal orange as the input signal is raised. Oddly, while the Bypass button is illuminated, it indicates that the Biscuit is not bypassed. Press it, the light goes out, and the raw signal passes through uncoloured by the 8‑bit stereo converters or other electronics. Perhaps the label 'Active' would have been clearer — not that I'm fixated on conventional terminology. I mean, who can resist a gizmo with knobs labelled 'Brain', 'Naked' and 'Dressed'? To learn the meaning of these impishly‑named controls, let's first confront another new term: biscuiting.

Taking The Biscuit

The Biscuit's job is to receive pristine drum loops, bass lines, et cetera, and spit out considerably less perfect 8‑bit equivalents. Having reduced your audio to just eight bits, a row of rectangular buttons are the key to chopping it still further. In this row, a white button represents an active bit, red an inverted value, and if unlit, the corresponding bit is muted. This is a top-notch visual aid that shows the converters in action; you instantly discover that switching off the top bits (buttons six to eight) will introduce the most severe harmonic distortion, while losing the lower ones (one to three) creates more subtle results.

That, in a nutshell, is 'biscuiting' — and its effects vary enormously according to the source material and input level (Drive). The manual recommends setting the Drive control so that the Bypass button flashes regularly from green to orange. Drive offers +15dB of gain, further increasing the potential for loud, distorted noises. A compressor/limiter is therefore a recommended safety net — especially in a live situation.

There are several built‑in shortcuts to speed things up, such as turning on, inverting or muting all eight bits in a single operation. In the latter case, muting kills the 'Dressed' output entirely. Here I should reveal that Dressed equates to Wet on a conventional effects unit. It is no great leap of imagination to realise that Naked refers to the Dry, unadorned signal. Naturally, I promise not to gratuitously employ these terms; there will be no reaching for the 'Naked knob', for example.

Biscuiting can be gritty; sometimes it's crunchy enough to shake your fillings — but it's just one of the available types of low fidelity. For the discerning grungeophile, good old‑fashioned aliasing can be dialled in with the Clock control. This live adjustment of sampling frequency goes from 30kHz down to 250Hz. It starts with a little high‑frequency fizz and travels through ring‑moddish atonality, before, finally, your signal is engulfed in screaming distortion that's packed with more artifacts than the Cairo Museum.

Some of the combinations of biscuiting and sample‑frequency reduction can feel like an aural assault, so it's just as well there's a means of calming things down. Enter the stereo 12dB multimode filter — an analogue 'happy ending' positioned after the 8‑bit DAC. Its designer, Denis Cazajeux, looked at filters from the Korg MS20 and Oberheim SEM, before building his own using similar components. To my ears, he did a great job, giving the low‑pass, band‑pass and (especially) high‑pass modes considerable character. Although the resonance differs from that of a synth (it more closely resembles the Q of a mixer's parametric EQ), the filter has a positive effect on everything it touches — so much so that I wanted to hear it let loose on a pure signal, one unscathed by the 8‑bit converters. However, the filter's raison d'être is to process the 8‑bit output, so I shouldn't really complain.

The Biscuit's back panel legending is printed upside down for the benefit of bats and those wanting to look over the top to plug things in.The Biscuit's back panel legending is printed upside down for the benefit of bats and those wanting to look over the top to plug things in.

The Brain

A choice of 8‑bit effects is found by activating the 'Brain'. As of version 1.2 of the Biscuit's operating system, these are: Vibrato, AR Envelope Filter, Tube Clipper, Waveshaper, Delay, Pitch Shift and Step Filter. Most of the effects' names are printed on the panel, although those that were added later are not. With the Brain button lit, select an effect with the relevant button (for example, Waveshaper is activated by button 5). Further parameters are then selected using the '+' and '–' keys (also labelled F1 and F2). In the case of Waveshaping, there are eight possible waveshapes, and as a general rule for all effects, the Clock control does data entry.

Since I've mentioned Waveshaping, let's start there. One of the shapes takes the name of the unit itself — Biscuit — and is described as "a fifth-down effect with crunch saturation added”. Other shapers include Bat Fuzz, Rectifying, Swap, and Low Alternate Rectifying. There isn't space to describe each in detail but they perform mathematical operations on the signal or the converter. The resulting audio transformations vary hugely depending on the Drive setting, audio source and sampling frequency. You can expect dirty, noisy harmonics, fuzz and even downright destruction, yet also subtle colouration and warmth, especially when you blend the Naked and Dressed signals sympathetically.

Of the eight waveshapes, the final three act as synthesizers that follow (or try to) the pitch of the input signal. When any of these are selected, the Clock control becomes a simple filter envelope for the generated waveform. Bass synth sounds proved to be the best candidates for tracking, although I never enjoyed complete accuracy or predictability. Fortunately, it turns out that going off the rails is far more entertaining anyway, just like in real life.

Two of the effects added after the initial design are the AR (Attack Release) envelope filter and vibrato. Vibrato is created from a short delay modulated by an LFO. The delay time is offset slightly between the left and right channels, giving an expansive stereo image. With its rate set by the Clock control and with no other parameters to tweak, vibrato offers an instant means of warming the chilliest of digital synths.

The AR envelope filter produces impressive filter blips and sweeps, especially from the band‑ and high‑pass modes of the filter. Clock is used to morph through a range of Attack/Release envelope shapes, while the filter Freq knob becomes a dual control over frequency and envelope amount.

Turning next to the delay, this is a mono effect sourced from the left input only. Tap tempo is used to set the delay time or, if you prefer, the Biscuit will happily sync to incoming MIDI clock. Buttons 2, 3 and 4 (known also as F1, F2 and F3) are used to set the three delay parameters, which are: clock subdivisions (from quarter notes up to dotted 16ths), feedback and 'Free Clock'. Activate the third of these options and synchronisation is bypassed, whereupon you can dial up a delay time directly. The parameters do what you'd expect from any delay — except they're rendered in 8‑bits. This produces easily the most unclean repeats I've experienced since a bout of food poisoning I once had. A big part of the freakiness is due to the automatic lowering of sampling frequency as the tempo slows down.

Incidentally, if you leave Brain mode with an effect parameter still selected, the Clock knob maintains the assignment, thus becoming a simple performance control for cranking up delay feedback, sweeping delay time and so on.

Another mono effect, the pitch shifter, is to precision and accuracy what Ann Widdecombe is to grace and elegance. Choose from one of eight possible intervals ranging from a two-octave downwards shift to an octave up, passing through several commonly‑used intervals en route. There's a detune option too, which I found fairly disgusting, but even that can be partially redeemed, thanks to the omnipresent filter.

Finally, and recalling Moog's MIDI MuRF slightly, the Step filter can automate a sequence of up to eight filter changes. Each step can store a different filter mode, as well as Freq and Q settings. As with the delay, the step filter syncs to MIDI clock or to a tempo tapped in manually. You determine the number of steps and the tempo multiplier (with a range of 1x to 24x but no half or quarter speed) and, finally, decide whether the sequence should run forwards or in alternating or random directions. There are quite a few options packed into the simple interface, so this effect takes a little longer to get the hang of, but it's worth the effort. And having created a fab step-filter pattern, you'll probably want to store it somewhere...

MIDI & Patch Storage

There are 16 user memories, accessed by holding the Brain and Filter buttons for a couple of seconds, then pressing one of the bit buttons flashing in white. Every button and knob position is memorised, and if you're wondering how eight buttons translate to 16 locations, the Brain button is used as a toggle.

If that's not enough, there are 16 factory presets, dialled up by holding the same two buttons a little longer. You can tell when you've waited long enough, because the white buttons change to pink. If more patch storage is needed, keen Biscuiteers can offload user memories as system exclusive data, plus there's another memory pool that holds eight snapshots of favourite bit configurations.

Some thought has been given to knob position after memory recall, leading to an unusual but effective implementation. If you turn a knob that deviates from its stored position, an automated value slide occurs, lasting about a second and neatly smoothing any jumps. You can peak at a stored value, if so inclined, by holding the Brain button and turning a knob. When the stored value is reached, the Bypass button turns blue.

All the panel's knobs and buttons send and receive MIDI continuous controllers. I noticed that one of the CCs chosen is usually reserved for bank select (CC32) but assuming that your sequencer doesn't impose any petty restrictions, this shouldn't cause a problem. The Biscuit's MIDI spec is pretty good and includes the receipt of patch changes and of notes to transpose the pitch shifter, plus various data filters and local on/off.


Contrary to what OK magazine would have us believe, there is value in imperfection. Maybe it's just my contrary nature, but the closer I get to achieving pristine, uncoloured audio, the more it feels like something is missing. So the Biscuit could be a timely product for anyone pining for grit, distortion and noise. It's also ideal for dirtying up virtual instruments, drum machines and samples, either by adding a touch of aliasing and bit reduction or something much more drastic. Just one afternoon spent biscuiting an Electribe gave me a large collection of loops that were glitched, shifted, rectified and pulverised before each being given the finishing touches from the analogue filter.

Oto Machines are a small company who were clearly delighted when the first run of Biscuits sold out. The second run is already pre‑sold to waiting users and distributors but there are plans for another batch (of 500) in 2011. So if you have any interest in 8‑bit audio, now's the time to check out some of the YouTube video demos. This isn't a processor for everyone — it's not quite cheap enough or generic enough for that accolade — but if your 'in the box' mixes are sounding a bit claustrophobic or lifeless, or you want to give your loops and bass lines more attitude, a few munches of the Biscuit might be just what you need.  


The last time I encountered such an abundance of distortion shunted through a classy analogue filter was the far more expensive — and mono — Evol Fucifier. The Biscuit's crispy tones occasionally reminded me of the Sherman Filterbank or even Moog's Freqbox, while its stepped filter effect has parallels with Moog's MIDI Murf or Linn's Adrenalinn. Korg's Kaoss Pads, too, offer some degree of lo‑fi competition but the closest (hardware) product that comes to mind is Frostwave's Sonic Alienator. As this is available only from the company (in Australia), I've never seen one.


  • Wonderfully gritty 8‑bit stereo converters and rate reduction.
  • A range of 8‑bit effects including delay, pitch shifter, step filter and waveshaper.
  • Multi-mode analogue filter.
  • Solid, hands‑on and decidedly different.


  • Not everyone will appreciate the sound of 8‑bit.


This Biscuit can break your audio into crunchy 8‑bit fragments. It combines bit and rate reduction, waveshaping, delay and a stereo analogue filter to make a lo‑fi toolbox with a unique personality.


€529 including VAT.

OTO Machines +33 (0)1 83 56 25 89.

Published January 2011