Circuit Mono Station: Behind The Scenes

The Making Of Novation’s Paraphonic Sequence Synth

The Novation product design team knew they were on to something as soon as they fired up the Bass Station II. As it blasted though the PA system at Novation HQ, they could hear the wild and untamed sonic signature of its predecessor — 1992’s BassStation — through the abundance of different timbres it was capable of producing. With Bass Station II, punchy sub lines, p-funk-esque portamento leads, noisey snares and deep-house organ bass were all within reach, and the synth’s comprehensive control panel provided sound-altering potential aplenty.

Fast forward three years, and the team had similar feels about Circuit, Novation’s first ever groovebox. Circuit was fast, intuitive, and supremely powerful, and it became a hit because it let creators ‘make a track in a minute’ with its built-in sounds — and/or their own samples. Its menu-free user interface signalled a break from the monotony of screen-based beat machines.

But what would happen if you mashed the two products — Circuit and Bass Station II — together? Would the combination of one focussed monosynth and one super-intuitive sequencing engine come together to form a truly great product? The thought had crossed the mind of Alex Lucas, Novation Product Designer, while developing the original Circuit. “We’d always seen the value in classic sequence synths; the 303 is the typical example. But we felt that other products on the market fell short in a few areas. So we wanted to take the standalone sequencer/synth concept and push it a little bit further.”

But mashing two products into one — despite being from the same company — is not as easy as it sounds. On the synth side, there was the task of reworking the engine of the Bass Station II — a keyboard instrument — into an inch-thick groovebox with nothing but pads, sliders and knobs, without compromising its trademark sound. With the sequencer, the team had to devise the behaviour and layout of the new device, then write the code to make it work, all while maintaining the idiosyncrasies that make Circuit unique, intuitive and engaging.

Design And Product Realisation

Before a product can come to life, several stages of development are required. Block diagrams of how the unit will work help the team to spec the hardware and software needed to make the product operate. Then there are the top-panel mockups that show how it will look, which help developers devise the way the user will interact with it. Importantly, this phase — called Design and Product Realisation (DaPR, or “dapper” for short) — must be fully completed and locked down before the design team hand the product up the chain to the engineering and manufacturing department. “The DaPR process helps us avoid getting ahead of ourselves,” says Alex Lucas. “If you’re developing a product’s concepts and trying to design it at the same time, that can cause disruption. For example, if we change our minds about the positioning of the controls half-way into the engineering phase, moving them can be complicated and costly.”

A sketch from Alex Lucas’ notebook, showing the basic schematic of Circuit Mono Station.

With the designs living in the 2D domain — often printed and plastered on the walls around Novation HQ — the team can spot problems before the product reaches the engineers. At this stage, designers can also propose new features and float ideas for expansion of a device’s capabilities. One such advancement that came out of the early development phase was to make the synth paraphonic. At first, the intention was to transplant Bass Station II’s synth engine in its original, monophonic form. But as the team pored over the prototype drawings, paraphonic functionality emerged as something that could greatly expand the potential of Circuit Mono Station — and set it apart from the other offerings on the market.

Long-serving Novation Hardware Engineer Nick Bookman recalls the moment Circuit Mono Station gained one of its most notable features. “It wasn’t long after we started the development process that Alex [Lucas] came up with the idea of making it paraphonic. Paraphonic basically means that you’ve got individual control over the oscillators, but they are summed and run through one filter and one VCA. Which means that every subsequent note that you hold down will re-trigger the filter and the VCA.”

“You can get a really interesting interplay between the two oscillators and their sequences” — Alex Lucas

These functions make a lot of sense in a sequencer-based product. “What Circuit Mono Station is capable of, in contrast to other paraphonic synths, is to sequence paraphonically in a standalone way,” says Alex. “Not only can you create a pattern for each of the oscillators, you can also set different pattern lengths and playback styles for each, so you can get a really interesting interplay between the two oscillators and their sequences.”

Another way to use the paraphonic-ness of Circuit Mono Station is with the ring modulator, as Nick Bookman explains. “Because the effect of the ring mod is dependent on the frequencies that you put into it, you can get some really interesting and unpredictable sounds. If you start changing between a 3rd and a 5th, and a 4th and a 5th, for example, you get quite a different timbre. It’s not just a different interval, it’ll be a completely different sound. It’s almost like putting a different patch on each note.”

The expansion of the modulation options was another important outcome of the DaPR process. As a veteran Novation product designer, Nick Bookman is capable of ‘hearing’ a synth simply by looking at the block diagram and the design mockup. He recalls a lightbulb moment during the development phase. “As I was looking over the plans, I saw the opportunity for there to be more modulation options, to increase the range of sounds possible. So I suggested this to the team and they were able to expand the power of the mod matrix. Now it’s an all-encompassing, any-source-to-any-destination matrix, which allows for a greater variety of sounds to be made. For example, you can combine sources to destinations, and do things like use an envelope and an LFO to go to a filter, or have individual control over Osc1 and Osc2. That sort of thing wasn’t possible before: you had one source to one destination.”

Sketches of the top panel from Alex Lucas’ notebook.

Entering The Engineering Phase

After several iterations, with the product design and specification locked down, Circuit Mono Station was taken from the drawing board and passed to the engineering team. The first stage of this handover requires someone experienced in all areas of product development to elaborate on, and translate, the top-level goals laid out by the designers. This ‘idea shepherd’ (Product Executor is the official term) for Circuit Mono Station was Paul Whittington, “I take the designs down to the deepest level, in order to work out how we’re going to implement all the wonderful ideas in the design. It’s basically a problem-solving process around exactly what the design is asking us to do, then making it real, easy to use, and easy to develop — always with the end user in mind.”

Key players in the next phase were Joe Crook (software lead) and Ben Cochrane (hardware lead). Joe had been involved in designing the intuitive behaviour of the original Circuit, so it was natural for him to be leading the software development of Circuit Mono Station. [In this instance, ’software’ refers to the code that Circuit’s on-board processing components use to do everything from running the sequencer, to illuminating the LEDs and switching between views.]

Joe had a familiar starting point: the original Circuit, the development of which he was still involved with. But there was still a lot of modification and iteration needed to adapt the original code to Mono Station. “I pulled a lot of code from the original Circuit,” says Joe, “then added a bunch of stuff, took some things away and then smooshed it all together, you could say.” Sounds simple, but with thousands of lines of code, it’s no mean feat. Designing the behaviour of the sequencers was one challenge. “Because the concept of paraphony is new to people, the sequencer behaviour was hard to define. It’s the most characterful part of Circuit Mono Station, but it was difficult to specify how it would work when it’s interacting with other features. We had to devise new modes to deal with the fact that it does some really weird stuff!”

“We’re constantly trying to balance the new features with the question ‘is this still easy to pick up and use?’” — Joe Crook

All this programming must be done with a watchful eye on the usability of the device, says Joe. “Our user interface is a 4x8 screen of pads with no menus, just labels to mark the different functions. We try to design the device so that the user can go into one of those pages, with no words at all, and know pretty quickly how they’re supposed to interact with the product. That stuff is always really difficult, and as you try to squash more and more features into the product, you find that it can easily compromise the ease of use. So we’re constantly trying to balance the awesome new features with the question ‘is this still easy to pick up and use?’”

The behaviour and layout of Circuit Mono Station, in illustrated form. (Picture: Alex Lucas.)

Then there were the improvements to the existing sequencer features of Circuit, such as adjustable sync rates, which are new to Circuit Mono Station. “The new sync rates let you play patterns faster or slower,” says Joe. “While this sounds super simple, the impact it has on an already complicated sequencer is massive — it affects every other feature you can think of! When we designed the sequencer for the original Circuit, sync rates and independent swing were not in the spec, so they weren’t built in. And, while we try to put hooks in when we can, to make the code expandable, it was a case of rewriting code in lots of different areas to make those features work. You keep thinking that people have been making sequencers for years, and that you’re probably dealing with problems that they faced. But when you combine the unique features of Circuit Mono Station, you realise that actually no-one’s come up against these problems before!”

“The goal is not to make complicated things; the goal is to make advanced functions, which are deep to master, but easy to use.” — Paul Whittington

Paul Whittington recalls one feature that didn’t make the cut. “There was a very complex glide feature in the initial design, something that sounded really cool on paper. We fought hard to keep that feature in, but in the end it was too technically complicated — we were having trouble explaining it to ourselves, let alone to people outside the team, such as our customers. That’s a big warning sign to say ‘maybe you’re overcomplicating things’. So we made the decision to change it, make it simpler and make it easier. The goal is not to make complicated things; the goal is to make advanced functions, which are deep to master, but easy to use.”

The Big Squeeze

Ben Cochrane’s role on the Circuit Mono Station project was to take the synth engine from Bass Station II and make it compatible — both physically and electronically — with the new form factor. The initial challenge was deconstructing the Bass Station II into its core parts. “My first job on Circuit Mono Station was actually to figure out how the Bass Station II worked!” recounts Cochrane. It was critical that the sonic signature of the synth — created by veteran designer Chris Huggett — was kept intact. But with a radically different physical layout required for Mono Station, plus new areas of functionality to implement, Ben had to basically start from scratch. “I spent a lot of time working with the circuitry and collaborating with the firmware guys to understand the interaction between the firmware and the hardware, so that we could integrate Bass Station II’s synth engine with the Circuit-style control surface.”

Ben had recently transferred from Focusrite, Novation’s parent company, as the Mono Station project was entering the engineering phase. At Focusrite, he worked on designing the mic pres and other high-quality analogue audio circuitry in the Clarett range of audio interfaces. Turns out this is a wholly different discipline to designing synths. “The first audio testing I did with the Bass Station II engine was to measure the sine wave. It had 3% THD! [Total Harmonic Distortion] and, while this figure is fine for a synth, it would be completely unacceptable in a high-quality audio circuit. Developing things to be deliberately distorted was a strange experience when you’ve been spending all your time trying to make your audio signals distortion-free!”

Circuit Mono Station features three types of analogue distortion effects, the design of which fell under Ben’s supervision. Distortion #1 is from Bass Station II, where an Operational Transconductance Amplifier (OTA) is overdriven. Distortion #2 is a completely new design, and Distortion #3 is the combination of #1 and #2 combined. (Similar to Bass Station II, Mono Station also has the pre-filter drive.) “Olly Burke [former product manager for Novation] had worked on speccing the feature set of Circuit Mono Station, and had identified the kind of distortion he wanted the product to feature,” recalls Ben. “But the thing with distortion is that it’s really non-linear, so trying to parametrically say what makes it sound like that is incredibly hard. We would do listening tests and hear from the product guys that they want it to sound ‘warmer’ or ‘dirtier’. ‘Warmer’ often refers to even-order, low harmonics (seconds and fourths for example); ‘brighter’ probably has some odds in there, higher order. And my job was to tune the circuit to get those harmonics out. For even harmonics, I’m looking at asymmetric processing of the waveform. I might clip one side more heavily than the other. Odd harmonics tend to be produced by symmetrical non-linearities, so I might use a J-FET to produce lower-order harmonics and a transistor to produce higher-order ones. These are all tricks I can use to translate the sound that I think somebody wants — firstly into something that you might see in an oscilloscope or a spectrum analyser — and then try to translate that back into a schematic. It’s very iterative though, because it’s so subjective. You have to go round this loop of ‘I’ll make what I think you want, and we’ll iterate on it until it’s right.’”

Seeing The Bigger Picture

One skill of a good engineer is being able to envisage the finished product early on in the design process. It requires piecing together specification sheets, block diagrams, computer-generated mockups and, in the later stages of the process, 3D renderings, to assemble in one’s mind something that doesn’t actually exist yet. Of course, it helps to understand the user case of the intended customer. Joe Crook recalls his moment of enlightenment. “It took a little while to get my head around the product because I’m not a massive synth head, though I really enjoy using the original Circuit. But with Mono Station I wasn’t convinced about what or who it was for to begin with. Then we got the first working version of the synth and I spent one morning not having a clue what any of the controls did. Nick Bookman talked me through them, and I spent the next couple of hours making patches. Suddenly the signal flow made a lot of sense and I was starting to make sounds more purposefully; sounds that I actually wanted to make. In no time, I was completely on board with the product and I was like ‘yup, this product is mine, this is what I’m working on’. I was proud of that moment.”

“Like with any product, when you see the real, tangible thing, it’s a cool moment,” Ben Cochrane adds, “hearing it for the first time, we thought ‘we’ve got a synth and it sounds bloody fantastic!’ That was great; it’s the payoff for all the evenings spent hammering through the schematics and PCB layouts.”

Naturally, it didn’t take long for certain members of the team to push Mono Station to its limits. Ben continues, “you can do crazy things like feed its audio output back into its input, which is one of Nick Bookman’s favourites. Mono Station has an experimental element to it, and there are lots of hacky type things that you can do with it. But at the same time, it is really focussed. You have a synth and you have a sequencer: you can really quickly get the sound that you want. It doesn’t try to be all things to all people. It’s very targeted on a specific job and it does it really well.”


Circuit Mono Station was launched at Superbooth, Berlin, in April 2017. Find out more at www.novationmusic.com.