Analogue Solutions Impulse Command

Analogue Synthesizer & Sequencer
By Robin Vincent

Stuck in a synthesis rut? Tired of patching the same old sounds? Analogue Solutions have got just the thing...

'Thrilling' is a good word to describe my first experience with Analogue Solutions' Impulse Command. It responds to general intuitive knob fiddling with a wide range of sound and a surprising amount of movement. It's fat, fierce and fabulously fizzy. There's a lot going on and the sound field is so full that you start questioning whether this really is just a monosynth.

The Impulse Command is imposing on the desktop. It's in a wedge-like, laid–back console style with a black panel on a red base, where the top is ever-so-slightly wider than the bottom. The layout is a not–quite ordered scattering of red, yellow and glowing pots with two big knobs in prime position that hint at the duality of this synthesizer. And then, just to finish off the impressive physicality, a fan of three light beams spills out on either side from vents laser-cut into the case. This is one solid and inviting piece of synthesizer.

But Analogue Solutions don't want to call it a synthesizer, they prefer the term 'sonic realiser', and now that I've spent some time with the Impulse Command I'm starting to understand where that idea comes from. The Impulse Command is at a basic level a subtractive, semi-modular monophonic analogue synthesizer. But Analogue Solutions designer Tom Carpenter is not content with adding another monosynth to their range or to the crowded monosynth market. Instead Tom has woven a sense of adventure and discovery throughout the device. He's made creative decisions that push you in different and often unexpected directions. And as with any thrill ride, you have to go with it or risk losing limbs.

Impulsive Behaviour

But first, the facts. The Impulse Command is a dual–oscillator, dual–filter analogue stereo synthesizer with two LFOs and two ADSR envelopes. The first oscillator offers sawtooth, triangle, pulse (with PWM) and noise waveforms. The second oscillator remains resolutely square and you'll also find a square–wave sub-oscillator. There's an analogue and a MIDI sequencer and at the end of the signal chain you'll find some digital effects. Not an unusual combination of features to find in a synthesizer, but perhaps some of the duality is beginning to raise your eyebrows. But it turns out that every section has its own level of surprise and playful weirdness.

The oscillators don't use a traditional form of mixing. The level of VCO 1 is fixed and hard–wired to a VCA controlled by EG 2. VCO 2 and the sub-osc are routed to the same VCA but are dynamically controlled. They have an IL or 'Initial Level' (like that found on the Yamaha CS synths), which acts as a volume knob, but from that point further level is added via MIDI velocity. VCO 2 can also be switched to use EG 1. Both have Amount knobs to dial in how much of this dynamism you want to use. Pulse-width modulation is available on both VCOs but only as a combined control over the intensity of modulation from LFO 2 rather than control over the pulse width itself. Analogue Solutions don't want you to get hung up on details like mixing waveforms or modulating the pulse width, they want to push you into experimentation rather than purposeful parameter placement. That's going to become a bit of a theme with this synth.

The rear panel houses MIDI in and thru ports, three audio outputs, an audio input, and a socket for the external PSU.

To get sound out you either have to connect a MIDI keyboard or an external CV pitch and trigger, or run the internal sequencer on LFO mode, which we'll come to in a minute. It's interesting how the feel of the Impulse Command is different when using a MIDI keyboard rather than a sequence. The MIDI velocity is tied to different parameters and so you get some unexpected and variable tones going on. The MIDI implementation gives it a whole other feel that you don't really experience in the sequencing, so when playing from a keyboard you are rewarded with different tones and unexpected velocity-based modulation.

Bringing up the VCO 2 IL and playing with the Detune knob thickens the sound with a rather unruly beauty. You have about 4-5 notes of play, letting you set up some nice thirds and fourths if you so wish. Bring up the IL on the sub and it treacles out to a golden syrup of sweet, fat synthiness. Add a touch of PWM to the phasing of the oscillators and you are already on to a first-class undulating lead or bass sound. There's always movement in there somewhere, and when you add the second oscillator or sub, it becomes a living thing.

It's in the filter section where the real fun begins. The Impulse Command has 'dual analogue 24dB filters'. These are not two independent filters; this is a dual filter with all sorts of shenanigans going on. There's a single low-pass filter with resonance and a nice big cutoff knob. Then there's a second cutoff that works as an offset relative to the first. The main cutoff (VCF-L) is panned left, the offset (VCF-R) is panned right, and this does very interesting things to the sonic field. Dial the VCF-R a bit forwards or backwards and you get a remarkable separation between the peaks. Rather than simply filtering a sound you are now dealing with the interplay between two filters that have a relationship to each other while acting independently in the stereo field. That's a lot more fun than it sounds and not something you usually get in a filter section.

Although the two peaks sweep together as you sweep the cutoff, they do have independent modulation possibilities. You can choose either envelope or either LFO to modulate each filter independently with control over depth. The filters don't have their own dedicated envelope. Envelope 1 could be controlling the level of oscillator 2 as well as either filter. Envelope 2 is always controlling the VCA of the oscillators but can also act on the filters. As much as you may like to separate Impulse Command out into separate processes it just keeps weaving things back together again.

There's no CV or modulation control over the resonance — if you want to mess with that then you'll have to get your fingers in there — and there's no boost to compensate for the drop as you push it up. There's a switch for flipping the modulation on VCF-L that gives you a whole other bunch of possibilities. You can also introduce some MIDI velocity on top of whatever modulation you're using so far.

And then there's the Aggro knob. This knob adds cross modulation from the second oscillator to the filter cutoff. It brings in an edgy sync/FM style sound that you can really push with the peak (resonance) knob.

The Impulse Command is a rollercoaster journey of discovery in a fat, oozing wedge of a synthesizer

Sequencer 1: The Sequercizer

To this feast of filter modulation we can add one more course — the sequencer. Or rather the 'Sequercizer' as Analogue Solutions have decided to call it. At the bottom of the synth are two rows of eight knobs, slightly offset, with glowing caps like those found on their Generator sequencer. This is designed to mess about with the filter cutoffs. It can do pitch if you wish but it's not normalised. There's a CV out send knob and you could patch the corresponding output back into the oscillator, but really this is all about the modulation. You can choose how much the Sequercizer impacts each filter separately and this is what starts building the impression that this is much more than a monosynth.

The Sequercizer can be driven internally by LFO 2 or via MIDI or a CV clock input, and although it's not patched to the pitch of the oscillators it is patched to the gate and so when you set it going you're getting a pulsed single–note sequence whether you want it or not. You can then use a MIDI controller keyboard or external CV to transpose the pitch. Extending the release on EG 2 gives a good approximation of a rather delicious–sounding drone while the steps modulate the filter. Apply a snappy envelope from EG 1 to the VCF-L and a slow-moving oscillation from LFO 1 to VCF-R and you've got a host of modulation and movement pulling melodies out of those filters.

But the Sequercizer has one more trick up its sleeve and that's the Reorder knob. As we've seen in the Fusebox and the Generator, Analogue Solutions like their creative pattern generation. The Reorder knob selects an alternative pattern for the steps. These are not randomly generated, they are purposeful and designed to be musical. There's a bunch of options in here, from running every fourth step to seemingly random but repeating patterns, all the way to reverse. They seem to follow from the current step rather than resetting from step 1. It's a load of fun to play with and is a great way to add some unexpected interest to a sequence that's been running for a while.

Sequencer 2: MIDI Loop

The Impulse Command's love of MIDI is consummated in the MIDI Loop Sequencer. This is probably based on the one found in Analogue Solutions' Treadstone synthesizer and is a simple and fabulously fast way to sequence notes into the Impulse Command. With the sequencer in 'stop', enable the MIDI Loop and whatever 16 notes you play next will be stored in the sequencer and played along with the Sequercizer. You can alter notes during playback — that's a little bit of a hit–and–miss affair if you're trying to do something specific, but a load of fun during performance if you're not too fussy. Turn on the Transpose button and can use your keyboard to transpose the sequence rather neatly on the fly.

The Impulse Command's less than conventional front panel — how many of your other synths have an 'Aggro' knob?

There's a Step button so you can select individual steps and change that note when stopped. The Step button can also force the Sequercizer to skip steps but doesn't affect the MIDI Loop and so potentially changes their relationship. Nothing's very certain in this synth. Just when you've got the measure of it you'll discover another way to mess it all up in really pleasing ways.

One thing missing from the sequencer/Sequercizer is any control over the gating. There are no gate patterns or 'rest' options. However, the MIDI Loop Sequencer is designed to give you some rhythmic flexibility. Rather than using the repetitive emotional void of MIDI Clock, the Impulse Command responds to MIDI Note 0 for step advancement. So, you could run a series of Note 0's from your DAW in a loop and generate all sorts of rhythmic patterns. You can also use Note 1 to reset.


At the end of the signal chain we find eight digital effects; a few delays, reverbs, a flanger and bit-crusher. Some in mono and some in stereo. Each effect has two parameters you can play with and there's a wet/dry mix knob at the top. The effects are nice and helpful but they also form part of the game of uncertainly that Analogue Solutions are playing. The Effects knob rotates all the way through the options without a click or a line on the front panel to let you know what you've selected. It's not difficult to work out, but it feels like a deliberate attempt at getting you to 'go with it'; to not be concerned about the precise selection but rather to feel your way into it.


And that brings us to Patch. This is the Impulse Command trump card. It's the unexpected and probably uncalled–for feature that you didn't know you needed, and even after playing with it for some time you still don't really know if you do. It's deliberately mysterious — Tom declines to answer any questions about it other than to suggest that it's there for exploration. If you've been trusting the synth and going with it so far then this is the moment of truth, this is the leap into the void. Perhaps I'm getting a little bit over dramatic... Basically, Patch does some re-routing voodoo behind the scenes and gives you something different to play with. I'd like to say it's like a preset but it's more like a curated patch.

There are eight patches using four internal signal routings, and through the use of MIDI velocity and the Sequercizer (oh yes, there's a send knob for Patch too) you can make some wild changes to what's going on. At a guess I'd say one patch removes the VCO 2 and sub, another throws the envelope on to the filter, another brings in PWM, another introduces noise and so on. The practical upshot is that you can select different patches for each step, which leads you into some rather nice rhythmic noise and percussive sounds interplaying with the duelling synth and filter melodies.


Although Tom has cooked up a certain amount of pre-patched goodness for you, it's also nice to find a decent–sized patchbay that releases you from playing the game and lets you inject some of your own modulations. You have CV inputs over the oscillators... no I was completely wrong, there's no escaping the game. There are two CV inputs that affect the pitch of the oscillators. The first one affects both oscillators like you'd expect, but the second one just affects VCO 2. So, plug the CV out of the Sequercizer to the VCO 2 input while running the Patch and the filters and the MIDI Loop Sequencer and we're into a whole other ride again. This thing is proper mental.

There's also a CV input on the PWM, the cutoffs of VCF-L and VCF-R, and a clock input to run the Sequercizer. The sawtooth waveforms of the two oscillators get an output each, which are asking to be plugged back into the pitch input for some sync/FM–style action. For modulation you get the triangle output of LFO 1 and the square output of LFO 2 that we didn't know we had. The envelopes get a trigger input as well as an output, so does the clock. On the back is the all-important stereo line output and a mono–mix output which I guess is important but seems a bit self-defeating. A single line–level input will patch some external gear directly into that dual filter. And then there's a MIDI in and a super helpful MIDI thru to make it a lot easier to integrate with other MIDI gear.

The patchbay doesn't give you every possible output. There are no individual waveforms, no resonance control or control over the Aggro or Effects. There's no Eurorack–level VCA output for the synth as a whole. But there's enough there to get the Impulse Control to mess with itself and be messed with by external means.


The Impulse Command challenges the notion of what a semi-modular monosynth should be. When you appear to have four melodies going on at once you start to doubt your synthesizer competence. The Sequencizer manipulates you as it starts to throw the filters around into different spaces, while repatching things you didn't quite expect and running off with a tune on the second VCO. All this while the MIDI is looping through a sequence as the velocity modulates the sub and the filter. It's an adventure playground of craziness, and just when you think you've got your balance you lose your footing and swing off down another pathway.

The oscillators are thick, the filters delicious and the envelopes are snappy enough to turn the whole thing into a percussive noise machine. And yet it's also capable of sweetness and tone that gives you some welcome respite before you start dialling the crazy back...

The Impulse Command is not a straightforward subtractive synthesizer. It won't give you the pure experience of the Mother-32 or the cerebral West Coast pathways of the 0-Coast. It's a rollercoaster journey of discovery in a fat, oozing wedge of synthesizer — or perhaps we should call it a sonic realiser.


  • Mysterious and surprising.
  • Thick analogue sound.
  • Dual filters in stereo.
  • Curated creativity.
  • Adventurous Sequencizer.


  • Strange in places.
  • Unpredictable.
  • Less than comprehensive patchbay.
  • Too mysterious for some.
  • Not cheap.


The Impulse Command is a craftily curated synthesizer adventure that circumnavigates the norms of traditional subtractive synthesis. It's fiercely analogue with a surprising range of sounds and sequenced rhythms that are split apart by the stereo nature of the dual filters. It's not like any other monosynth you've ridden on before.


£1018.80 including VAT.

Published September 2019

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