You are here

Modal Electronics Cobalt 8

Virtual Analogue Synthesizer By Robin Vincent
Published February 2021

Modal Electronics Cobalt 8

The Cobalt 8 is a beautifully judged virtual analogue synth.

When the Cobalt 8 arrived at my house the box said Argon 8 on the side, which should give you a bit of an indication about how much is shared between Modal’s wavetable‑based synthesizer and the new Cobalt 8. They are physically identical. Every knob, every button, the joystick, the connections on the back, they are all the same as the Argon 8. The only difference to emerge from the box was the shining cobalt blue aluminium front panel, which is really rather striking.

Despite the compact three‑octave size the Cobalt 8 is weighty, like it’s full of bricks. It goes down on your desktop with a satisfying thump and you know it’s not going anywhere no matter how much energy you put in the Fatar premium 37‑key keyboard. I’m surrounded by MIDI controllers and the feel of the keyboard is superior to anything within reach. It feels confident and satisfyingly heavy and, I don’t know, a bit posh for a compact synth.

The opening preset pulls in a delicious brass swell of analogue‑sounding waves that fill your space. Harmonics flow around you as you apply pressure to engage the aftertouch. Time passes like it does when you’re fully engaged in an activity and I find myself having a really lovely time. There’s a warmth to it, a playfulness, a vibe that keeps a smile on my face. It’s not obnoxious or deliberately edgy, it’s not hitting me with weird noise or trying to make me dance. It’s familiar, balanced, like a favourite song or even a favourite armchair. Playing the Cobalt 8 is perhaps the synthesizer equivalent of curling up with a really good book.

The Cobalt 8 is an eight‑voice Extended Virtual Analogue synthesizer. Virtual Analogue (VA) means that it’s a digital machine running DSP‑based software that recreates or models analogue circuitry. It’s a different form of sound generation to the Argon 8, which was based on wavetables; this is based on analogue waveforms.

We’re familiar with VA synthesizers as we’ve seen them before, whether that’s the classic Roland JP8000 and Korg MS2000, the Access Virus, Nord Lead or the more recent System‑8 and Jupiter‑Xm. It’s often argued that they are just VST Instruments in a box, and whether you are modelling analogue sounds on a computer, DSP or FPGA it’s all essentially the same. However, there’s something in the design of a hardware instrument, in the thought behind the interface and the technology choices that were made that elevates a VA hardware synthesizer from its virtual instrument cousin. With this ‘Extended’ VA synthesizer, Modal are all about the elevation.

The Cobalt 8 is a wonderful‑sounding synthesizer for grown‑ups who enjoy exploring both new and familiar territories without getting bogged down in the minutia.


The sounds start at the oscillators. The Cobalt 8 has 64 of those and the eight voices can use up to eight each. You don’t get access to individual oscillators like you would if they were actually there. Instead Modal offer us two independent oscillator groups that we control the nature of while the Cobalt 8 sorts out the individual details. For each group we can select one of 34 different algorithms to produce our starting waveforms. The first algorithm contains your classic analogue waveforms and you can sweep smoothly between sine, triangle, saw, square and pulse waves and watch the process unfold on the 1.54‑inch OLED screen. The rest of the algorithms are as if Modal have sat down with a modular synthesizer and crafted a whole bunch of interesting waveforms for you play with. There’s crushing going on, bending and wave‑shaping, a lot of pulse‑width being modulated, waveforms reflecting, sync’ing and fracturing. There’s some reversing, metalising, Ring Modulating, chaos, folding and even some noise to round it all off.

Modal have given us two parameters to play with for each algorithm. There could have been a whole number of things you could tweak but Modal have considered all the options and come up with the two they feel are the most musically interesting or applicable to the synthesist. It’s in this curation that the genius of the Cobalt 8 starts to emerge. They could have just given us an interesting waveform, but I think we would have felt short‑changed, or they could have overwhelmed us with possibilities, whereas to focus on a pair of really useful, effective and pleasing parameters keeps us interested, keeps things moving and brings in some tonal crafting that feels personal and unique to your own fiddlings.

This all happens in the Oscillator section of the front panel. You have separate knobs for selecting Algorithm 1 and Algorithm 2 and a Mix knob in between so you can favour or fade from one or the other. Above each Algorithm knob are two parameter knobs — A1, B1 and A2, B2. For me this is where all the action is. If I was designing this synth I would have put a lot more physical emphasis on the oscillator section. The filter is always important and that gets a larger knob, but I’m finding I spend all my time on the Oscillator section and it’s remarkably non‑descript considering its importance to the nature of the synthesizer. It also produces the most visually interesting things on the screen, throwing up waveforms with every change and animated movement. Modal have gone for a very symmetrical look where every encoder has the same sense of importance, but then that’s a necessary casualty of a shared hardware platform.

The first algorithm, which is your classic waveforms, gives you ‘Shape’ and ‘Spread’ to play with. Shape morphs through the waveforms from sine to pulse, whereas Spread starts by detuning its oscillators and then introduces intervals of a third, fourth, fifth, octave up and then a few octaves down for a good sub tone. Turning through the algorithms you get to play with detuning on the Spread tones, width and symmetry on the PWM section, ratio and sub‑oscillator blend on the Hard Sync ones, and it goes on from there into increasingly complex waveforms and a perfectly chosen pair of parameters. Playing with the algorithms is enormously satisfying and I could easily spend all my time here.

Beneath the Algorithms on the panel are four buttons that, through the cunning use of a Shift button, provide four different play modes. You can choose between Monophonic, Polyphonic, Unison and Stacked. Mono mode uses four oscillators stacked in a single voice, Poly gives us eight stereo voices, Unison is monophonic and can be set to two, four or eight voices stacked and detuned, and Stack stacks polyphonic voices. The Unison‑8 mode is so fat and juicy it makes my speakers rattle.

It’s all sounding quite perfect so far, which is exactly what you might not want. That’s where Drift comes in; a wonderful knob of seductive sloppiness. Drift adds increasing amounts of random detuning to replicate the failure of analogue components to hold a tune. It’s a really lovely thing. Combined with its accomplice, ‘Width’, you can push voices about the stereo field as they all gently fall off their expected pitches.

At some point you have to drag yourself away from the fascinating algorithms and visit the filter. In another departure from the Argon 8, the Cobalt 8 has a model of a ladder filter. It’s a four‑pole morphable ladder filter with a handful of configurations. The Morph knob takes your Low Pass Filter from a four‑pole slope through to Bandpass and then to a one‑pole slope. For the High Pass it does the same but with a Notch in the middle rather than the Bandpass. The Low Pass has two modes: Resonant to maximise the resonance response and Balanced to hold onto a bit more low end. The High Pass is also Balanced but I’m not sure it needs to worry too much about losing the low end. Finally there’s a Balanced Phase which is a rather nice dual‑notch in a 'W' shape.

Modal Electronics Cobalt 8 left control panel close-up

Filter, Envelopes & Modulation

The filter sounds great and fulfils its job perfectly well. It’s not exactly oozing with flavour, though. It’s a brilliant, clean, happy filter that sounds really nice, but it’s lacking a sense of overdrive or bite. But that also feeds into the general vibe of the Cobalt 8 in that it’s not particularly dangerous. I would say that the filter feels safe, but that would suggest that it’s not exciting, which is the wrong impression because it’s a very exciting synthesizer. So rather it’s ‘safe’ in a secure, solid and rooted kind of way. The one slight disappointment is that, particularly at higher resonances, you can definitely hear stepping as you turn the cutoff knob. This doesn’t seem to be there when you route in an LFO to take control so I can assume that it’s to do with the resolution of the knob rather than the filter itself, but I do like to turn a knob.

The Cobalt 8 has three ADSR envelopes, one for the filter, one for the amplifier and a spare one for modulations. They all share the same row of knobs with three switches to the side to move between them. A Depth knob takes care of how much envelope is applied and can also invert the filter and modulation envelope. If you hold down one of the envelope buttons while moving the knobs you’ll change all three envelopes at once which is a very natty little feature. There are eight envelope types, defaulting to a classic exponential curve, but they also offer a super snappy one and longer ones for pads with both linear and exponential curves. The differences are small and the place where you find them is pretty buried in the menu system, so if I wasn’t deliberately going through every parameter on the synth I wouldn’t have noticed they were there and it probably wouldn’t have mattered too much. However, they are nice and snappy down to the tiniest blip and the release can last as long as 10 seconds.

To complete the modulation side of things the Cobalt 8 has three LFOs. LFO 1 and 2 get their own button and knobs and LFO 3 is consigned to a Shift function. LFO 1 is global whereas LFO 2 & 3 are polyphonic. You have seven shapes to choose from, including Sample & Hold and slewed Sample & Hold, and you have control over depth and rate. The rate can be sync’ed or free, retriggered or free‑running and continuous or one‑shot. It doesn’t go dangerously fast, it’s well within safety limits.

There are 12 modulation slots in total. Four of them are already permanently occupied, leaving eight slots for us to play with. The four permanent fixtures are Note, Joystick Y+ (push), Aftertouch and Velocity, which are mapped to Cutoff, LFO 1 depth (vibrato), Cutoff and Amp Envelope depth, respectively. They have their own buttons over by the joystick and you can enable and increase the depth of modulation by pushing the button and turning the appropriate knob. The other available modulators are LFO 1, 2 and 3, the Mod envelope and the left/right movement of the joystick (X+‑) and pulling it back (Y‑). With 55 possible destinations there’s potential for a lot of modulation and those eight slots run out really fast.

Assigning modulation is dead easy: hit the source button, for instance LFO 2, and then simply turn the knob of the thing you wish to modulate. The amount of turn automatically gives you the depth of modulation and off you go. Once you dig into the modulation the interface starts to become a bit of a challenge. Keeping track of what’s assigned to which parameter can be difficult, button combinations become a handful and the menu starts to be a bit of a chore. For instance, if I want to modulate the shape of LFO 2 from LFO 3 you have to hit Shift, then LFO 2/3 button twice to latch on LFO 3, then hit Shift again to disengage it, hit LFO 2/3 button to select LFO 2, press Shift to enable you to turn the appropriate encoder for Shape, and you’re done!

However, it might have been easier to do it directly with the screen and the data knobs on either side where you can select sources and destinations by dialling through the options. The screen does a decent job of being a point of reference but I do find myself scrolling through it a lot looking for assignments.

It’s not badass, edgy or intimidating, it’s more like a good pint, in good company down your favourite pub. It has such an upbeat and positive vibe that you come away smiling and feeling very pleased with yourself.

My overall impression of the interface is definitely a positive one. You can zoom around turning knobs, investigating parameters and discovering what happens. It’s clearly laid out, spacious and easy to navigate. However, you never actually know what anything is set to. At a glance you can’t gather a single piece of information. You can’t get lost because you have no idea where you are to begin with. Unlike other synths with presets where the knobs no longer show true when you select the next patch, here you never have a hint of truth. The positive side is that it makes for a very exploratory experience. There’s no touch response, so you can’t place a finger on an encoder to see its value — you have to waggle it a little bit. The actual value of things lays behind the Page/Parameter encoder which will dial through every setting and every assignment and throw it up on the display as text. It’s not as jarring as that may sound. There’s a flow and an exchange in moving from organic encoder exploration to intentionally finding out exactly which modulator is doing that thing you can hear.

The Cobalt 8’s back panel features quarter‑inch sockets for headphone and audio out and pedal inputs, 3.5mm connectors for audio input and sync I/O, full‑size MIDI I/O ports, and a USB‑B port.The Cobalt 8’s back panel features quarter‑inch sockets for headphone and audio out and pedal inputs, 3.5mm connectors for audio input and sync I/O, full‑size MIDI I/O ports, and a USB‑B port.

There’s An App For That...

The Modal App provides a useful window into what’s going on inside the Cobalt 8.The Modal App provides a useful window into what’s going on inside the Cobalt 8.

I imagine that’s why we have the Modal App. If you need a deeper level of at‑a‑glance individual parameter precision then this is a whole app dedicated to showing the position of every single knob. It fills in all the gaps, you can see all the modulation slots and get deep into the sequencer.

Even with the app the thing that remains missing is any visual indication of modulation. While the little screen animates the changes you make to the waveform with the oscillator knobs it shows no reaction to having an LFO plugged in, neither does the filter. In fact there’s not even a flashing LED to suggest how fast the LFO is cycling. The app is also completely still until you move an encoder. The advantage that virtual and digital interfaces have over analogue is their ability to animate and show layers of information and that’s something I like to see. Otherwise the app, whether standalone or as a plug‑in, is an excellent companion to the Cobalt 8. You certainly don’t need it to enjoy the synthesizer but it can deepen your access and understanding.

Arpeggiator & Sequencer

Modal Electronics Cobalt 8 right control panel close-up

The Arpeggiator does its job and the Sequencer is certainly decent enough. It gives you real‑time and step‑record options of up to 512 steps or 64 steps respectively. You get four lanes of animation which you can record along with your sequence. It cleverly uses the lights above the 16 front‑panel buttons to show the steps, which is pretty neat. Sequences can be linked to a patch, so they will load up with it. Working with it is quite screen‑intensive and unfortunately you often have to navigate back and forth between two different pages. Most of the sequencer functions are under ‘Seq’ but others, like the totally‑awesome‑that‑it‑exists metronome, pre‑roll and quantise are on another page a few turns down the line.

If you know exactly what you’re doing and where you’re going and you don’t make any mistakes then it’s all seamless, but as soon as you have to do things over again it gets frustratingly menu‑heavy. This is another one of those places where the Modal app comes into its own. It gives you piano roll editing of the notes and you can draw in all the animations. Although if I’m connected to a computer then I might as well open my DAW for this sort of thing.


The Cobalt 8 is compact, measuring just 555 x 300 x 100 mm, but reassuringly weighty at 5.6kg.The Cobalt 8 is compact, measuring just 555 x 300 x 100 mm, but reassuringly weighty at 5.6kg.Last but not least, the Cobalt 8 has a three‑slot effects engine with a choice of 12 effects covering modulation, delay and reverb. They get three dedicated knobs to control the six available parameters. They all sound pretty good to me and once you discover that there are 100 effects presets hidden inside it really opens up the possibilities. We don’t get a distortion like the Argon 8, but we do get a ‘Lo‑Fi’ effect with a rather brutal bit‑crusher that strangles the sound down to a pitiful squirt — in a good way. If you’re in need of a boost there is a saturation option in the output menu that pushes the volume up against the internal limiter so it’s not without some oomph.


The Cobalt 8 is a synthesizer with a strong sense of itself. It’s familiar in all the ways that matter to someone wanting a polyphonic analogue experience. It’s not badass, edgy or intimidating, it’s more like a good pint, in good company down your favourite pub. It has such an upbeat and positive vibe that you come away smiling and feeling very pleased with yourself. It’s modest, likeable and enchantingly easy to program. The work Modal have done in curating the algorithms is fabulous and prevents you from getting bogged down in the initial elements of sound design, which sets you free you to play and explore. The Cobalt 8 will give you a lot of mileage and bags of joy.

Easy As MPE

Something that wasn’t part of the Argon 8 on release was MPE support; it came along later with the v2 firmware. The Cobalt 8 has it from day one and it’s superb. The keyboard isn’t equipped for that sort of expression so you will need to plug an MPE‑compatible controller into it. I connected my ROLI Seaboard and it worked perfectly. Along with polyphonic pitch‑bend you get Slide from a forwards/backwards motion and Pressure. Slide is mapped to whatever the joystick Y‑axis is mapped to, which is essentially operating as a mod wheel. Pressure is mapped to Aftertouch. It’s very easy to assign these to whatever you want to control. It genuinely adds a whole other dimension to the synthesizer and feels profoundly good. Too good for the sequencer, though, which ignores any of that MPE nonsense.


  • Sounds lovely.
  • Brilliantly curated algorithms.
  • Solid filter model.
  • High‑quality keyboard and build.
  • MPE.
  • Easy to use and program.


  • Menus can get annoying.
  • No visual feedback on modulation.
  • Could use more modulation slots.


The Cobalt 8 is a wonderful‑sounding synthesizer for grown‑ups who enjoy exploring both new and familiar territories without getting bogged down in the minutia.


£579 including VAT.