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Test: Modal Electronics Cobalt8 - Von eiskalt bis analog

Published 11:17 am on Monday 15th March 2021 by Beat Magazine

Robust and Chic

Externally, Argon8 and Cobalt8 are like two peas in a pod. Cobalt8 is housed in the same robust and heavy-duty casing, which is mainly made of thick steel and aluminum and differs only by the eponymous cobalt blue paint. This makes this compact synthesizer not only feel very high-quality, but it also makes it look really chic.

Very Good Keyboard

Fortunately, no expense was spared on the keyboard as the interface between sound production and the musician. The 37-key keyboard is a FATAR TP9/S with full-size keys, which supports velocity and aftertouch and provides above-aver age feel. Since the modulation wheel and pitch bender were omitted in favor of a joystick, the width of this synthesizer could be limited to the default of the keyboard. At about 55 x 10 x 30 cm, the Cobalt8 is, therefore, as compact as a Korg Minilogue or Wavestate, although it offers a decent full-size keyboard. Considering that Korg‘s current line with Wavestate, Opsix and Modwave is even a tad more expensive than the Cobalt8, and Modal is a small company with a much smaller run, the build quality is really outstanding in this price range! Like the Argon8, the Cobalt8 is also available in a large 61- key version, as well as a desktop version; but the latter is not much cheaper and you also have to do without some controls. If you don‘t suffer from an acute lack of space, we would recommend the 3-octave version over the desktop.

Encoder, Graphic Display

The knobs are designed as encoders, so there is no need to worry about value jumps after changing presets. The endless knobs are pleasantly large and easy to grip, and there is even a really large knob for the Filter Frequency. For our taste, the encoders are a bit too smooth - we would have preferred a bit more resistance when turning them. The values can be read on the centrally located OLED display, which is a good deal larger than on the Minilogue XD at 1.54 inches and is more comparable to the second display on the Hydrasynth. In addition to parameter values, it can also display graphics such as the currently set envelope curve or the waveform in real-time.

Sophisticated Operation

In addition to the knobs, there are several illuminated buttons available as well. Most of the knobs and buttons have a secondary function that can be accessed using the Shift Key. These additional functions are printed in blue on the panel, so you don‘t have to learn them by heart. You do have to be a little careful, however, so that you don‘t accidentally change the wrong parameter because you happened to overlook the activated Shift Key. The same applies to the five controls for setting the envelope. Here, you use three buttons to decide whether you want to set the parameters of the Amp, Filter or Modulation envelope. After a long press, you can conveniently operate the parameters of all three envelopes simultaneously. Overall, its operation is very practically solved; for example, you only have to press the LFO button and then change a parameter such as Cutoff with the knob, and the LFO will modulate the Filter Frequency. You can tell at every turn that the synthesizer was developed by a small team of enthusiasts who work with this synthesizer themselves.

USB for MIDI and the Editor

All connections are located on the back. Power is supplied via an external power supply, but at least there is a power switch on this synthesizer. The USB port is used to connect to a computer. Cobalt8 is class-compliant, so it works with iOS devices like iPad without the need for special drivers and sends and receives MIDI via USB. In addition, this allows communication with the free editor software, which runs standalone or as a plug-in on Windows, Mac and iOS; and allows convenient operation of every function, graphical editing of the sequencer, and saving and loading of sounds with the track in your DAW (Total Recall). Alternatively, there are two traditional DIN-format MIDI jacks as well.

Analog Connections

The input and output for analog sync are also very nice, allowing synchronization with devices such as the Korg Volcas or Teenage Engineerings Pocket Operators. Conveniently, a 3.5mm stereo jack input was placed right next to it to route the audio signals from these small synthesizers - or even a smartphone or MP3 player - into Carbon8 to process with its internal effects. This way, you may avaoid the need for a mixer in a live setup. Cobalt8 has two pedal connections for expression and sustain, as well as stereo audio outputs and a headphone output.

Digital Sound Production

The sound production in the Cobalt8 is completely digital and is based on the same DSP that is also installed in the Argon8. Since all controls are identical, one could hope for an option or a hack to turn a Cobalt8 into an Argon8 (or vice versa) by way of firmware; however, nothing is officially planned in this respect. Compared to purely analog synthesizers, the digital design has the advantage of storability and programming via the included app. With 500 editable memory locations, 300 of which are filled with factory presets, there is plenty of space to store your own creations.

Virtual Analog

The basis of the sound synthesis is formed by two identically constructed oscillators, which, in contrast to the Argon8, are not wavetable-based, but can be classified instead under Virtual Analog. They do, however, go far beyond the emulation of standard analog waveforms. Sync, ring modulation and other overtone-rich changes to the waveforms can be generated with one oscillator alone, there are 34 algorithms each that are available to choose from. Each of the two oscillator groups has two parameters that can be used to morph between waveforms and detune up to four oscillators against each other. In addition, there are Unison and Stack modes, as well as drift parameters and a continuously adjustable stereo width for wide and lively sounds.

Multimode Filter + Morph Function

The different algorithms can create very transparent - and also very complex - overtone-rich sounds, which are subtractively post-processed with a 4-pole filter. As already mentioned in the introduction, Modal has put a lot of energy and processing power into this filter and, in particular, the emulation of a classic ladder filter sounds excellent and convinces with a very „analog“ sound. Alternatively, there is a variant with a somewhat tamer resonance, which thins out the bass range a little less. In addition, a high-pass and band-pass filter are both available. With the Morph control, you can switch continuously between different variations of each filter type, which allows for very interesting sound characteristics when modulated by an LFO.

If there is any criticism to be made, it is the lack of a drive option for a warm start to the filter or a distortion stage behind the filter. Because the filter sounds rather nice and pleasant and sometimes a bit too well-behaved, an adjustable saturation would not have hurt here. Perhaps this could still be retrofitted via a firmware update.

Three Envelopes, Two LFOs

The first two ADSR envelopes are permanently assigned to amplifier and filter, the third envelope can be routed to a selectable parameter. A distinctive characteristic can be set for each envelope, for example, Snap for crisp basses and percussion or Slow for drones and pads.

The three LFOs offer a wide range of waveforms and reach speeds well into the audio range. They can run freely in the background or be retriggered with each note played; and can also be synchronized to MIDI clock. One LFO works globally, the other two are polyphonic and thus available for each voice individually.

Modulation Matrix

The LFOs are available for selection as sources in the Modulation Matrix together with other modulators such as Note Value, Mod Envelope, Velocity, Aftertouch, Modulation Wheel and the four axes of the joystick. These modulation sources can be freely distributed to different modulation destinations. Even if some connections are already pre-linked ( for instance, keyboard tracking of the filter), it can get pretty tight with the eight freely-configurable modulation slots. This is because the parameters of the built-in effects can also be selected as destinations, which allows, for example, rhythmically modulating reverb intensity, delay times controlled by LFO, or the fading in of a phaser via aftertouch.

Three Effects Simultaneously

The Effects Section of the Cobalt8 is quite lush and an important part of the overall sound. Three effects can be used simultaneously; and each effect slot can generate a stereo effect, with a choice of various delays, reverbs, flanging, phasing and chorus. The effects can be edited relatively extensively. Here, too, the control concept does without menu diving and relies on direct access via knobs and buttons. Cobalt8 offers three double assignable knobs just for this purpose, so you have access to up to six parameters per effect. A practical feature is the global Dry/Wet control, which allows you to fade out or add all effects simultaneously. Sonically, however, reverb and delay in particular don‘t quite come close to the level of the effects integrated in current Korg synthesizers. This is compensated for by the ability to modulate individual effect parameters via the sequencer or an LFO.

Polyphonic Sequencer

Cobalt8 also has a built-in sequencer with up to 512 steps. Recordings are made in real-time, a metronome and disengageable quantization feature ensure the proper timing. Subsequent editing is not possible - not even via the software editor. To be honest, we didn‘t really miss this in the test, but simply re-recorded the sequence quickly when necessary. Similar to the motion recording function on Korg synthesizers, up to four parameters can be recorded in addition to the notes, which allows for very lively and modulating sequences.

Step-Sequencer with Extras

Alternatively, there is a retrospectively editable step-sequencer with four automation tracks. Very conveniently, it can also be synchronized to incoming notes or sync signals instead of to the clock (internal or MIDI), which then advances it one step at a time. This is particularly familiar from DSI synthesizers such as Mopho or Rev2, for triggering new rhythms quickly and easily. This option also leads to exciting results if you use the arpeggiator and step-sequencer in parallel. Notes can be muted if you want a pure modulation sequencer. Sequences are stored separately from patches, but can be hard-linked to a particular sound.

Programmable Arpeggiator

The Arpeggiator offers not only different playback directions, but you can also enter your own note sequences, including rests, while holding down the Arp button and then play and transpose them by pressing a key. Unfortunately, these individually created arpeggios are not stored permanently, but are lost after switching off. Fortunately, Cobalt8 sends out the arpeggiator and sequencer data as MIDI notes on demand for recording in your DAW. The chord function is just as intuitively implemented: simply play a chord on the keyboard, press the Chord button, and you can play that chord with just one key.


Cobalt8 is a modern Virtual Analog synthesizer with a well thought out and quick to learn operational design. The oscillators and filter sound very good and allow for classic analog sounds that have a transparent and organic sound, somewhat reminiscent of Sequential/DSI synthesizers like Prophet08 and Rev2. But the flexible oscillators, as well as the extensive stereo options and the modulatable multi-effects, also allow for unique sounds like cutting leads, bell-like arpeggios and ice-cold pads that would not be possible with a pure analog synthesizer and head in the direction of hybrid classics like the Ensoniq ESQ1. In addition to the sequencer and arpeggiator, there is also the high-quality hardware with an excellent keyboard, which pleasantly stands out from the competition in this price range and emphasizes its character as a real instrument. All in all, this makes Cobalt8 one of the mostinteresting synthesizers in the sub-1,000 Euro price range.

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