Announcing Anushri

Mutable Instruments Anushri - a cheerful analog synth (that doesn’t suck at drums too)

Analog synthesis

  • Analog VCO with saw and pulse waveforms, freely mixable.
  • Optional automatic VCO calibration in software for those who don’t like messing with trimmers.
  • -1 or -2 octaves sub-oscillator.
  • Auxiliary square oscillator (DCO) with accurate digital tuning. Can be mixed in the audio path, used as a FM modulator or as a sync master for the VCO (yes, it means “ewwwwwwiowwww” and “wongwong”).
  • 12dB/octave multimode filter, with smooth self-oscillation.
  • Post-filter overdrive/fuzz circuit.
  • Linear VCA.

Modulation sources

  • 1 main ADSR envelope routable to pitch, pulse width, cutoff frequency.
  • 1 simple 1-parameter envelope (morphing through various stages, including the shape of the main ADSR, and a rigid “GATE” style envelope) routed to VCA.
  • Velocity routed to either cutoff frequency or VCA gain.
  • 1 LFO routable to pitch, pulse-width and cutoff frequency ; with 8 waveforms (triangle, square, ascending and descending ramps, S&H, bernouilli process, piecewise linear random process aka “autodubstep”, noise).
  • 1 triangle LFO for vibrato and/or growl.

Arpeggiator and sequencer

  • Arpeggiator with 4 modes (up, down, up&down, random) ; 1 to 2 octaves ; 6 patterns.
  • SH-101-style note sequencer with step by step recording, up to 128 notes. Easy recording of pauses, ties, and glides.
  • Tempo set by internal clock with shuffle, external MIDI clock or external 6/12/24 ppqn trigger.

Drum machine

  • Algorithmic drum pattern generator using an innovative “pattern sculpting” approach - allowing a large combination of drum patterns to be sculpted from 5 knobs.
  • Digital sound generation of BD / SD / HH with tone control.
  • Drum sounds can be freely triggered from an external sequencer using MIDI channel 10.


  • 10 pots and 4 switches for hands-on access to synthesis parameters.
  • 10 “software-pots” for editing modulations / arpeggiator / drum machine settings.
  • 3 dedicated navigation buttons (“modulations”, “arpeggiator / keyboard”, “drum machine”).
  • 3 dedicated sequencer buttons (“record”, “play”, “hold / rest”).


  • VCO CV in/out (Note: manual VCO calibration is required for accurate 1V/Oct I/O).
  • VCF CV in.
  • VCA CV in.
  • PWM CV in.
  • Gate signal in/out (5V level for output).
  • 24, 12 or 6 ppqn clock signal in/out (5V level for output).
  • Front panel external audio in.
  • External Audio in.
  • Drum machine individual out (inserting a jack there removes it from the main mix).
  • Audio out.
  • MIDI in/out (thru + arpeggiator and sequencer notes).
  • CC control over modulations and some of the digitally controlled synthesis parameters. Some parameters like filter resonance cannot be CC-controlled.


  • Remove main audio in / out and solder corresponding minijacks on PCB
  • Remove LT1054 and solder 2x5 power connector
  • Route MIDI in/out to front panel (if you want…). And that’s it!


  • DIY product (full kit)
  • Price < 200€ / kit
  • Available < October 2012

Demo with drums
Synth demos

TODO list:

  • Add VCA and PWM CV in if possible
  • Add sub level pot if possible
  • Add a 10th soft pot and implement cool features for it
  • Add a “hidden” way of programming a drum pattern for those who insists on it
  • Revise top panel layout
  • Make the boards assembly slimmer
  • Case!
  • Polish drum machine code. For now, HH is a sample, I’ll replace that with synthesis if possible. Drum generation engine was trained on ~ 48 bars of drum patterns, “the musical brain is learning”.
  • More tests!

But we’re almost there, it’s cool :slight_smile:

And for those who are wondering, the drum machine engine started as Eigendrums, except that EVD / PCA was not a good idea for dimensionality reduction. It was then “Kernel-PCA drums”, “Locally Linear Embedding drums”, and is now “Kohonen-Map Drums”.

sounds awesome. i didn`t dream about something that powerful after you wrote it would be a “dumb” machine

this bites monotribes ass!

What ‘flavour’ is the filter? OTA?

And Eurorackable - c’est magnifique!



How the drum machine works:

You have 9 knobs to control it.

3 or them are “morphing” through different types of drum sounds for BD / SD / HH. Sort of a magic 1 button “tone control” that goes from 606 to 909 through all possible values including 734.

1 of them is BD vs SD/HH xfade.

2 of them are controlling the “genre” in which the drum engine improvises (yes it does fluctuate and add some random variations when it fancies). Technically, it’s the X/Y position on a Kohonen Map learned on a bank of 48 drum patterns that I recorded in a hurry thursday afternoon at 3 PM. Will train the model on more and better material later.

3 of them control how much the pattern is “filled” with BD, SD and HH. Set to 0 and you have something with none of that instrument. Set to max and it’s 16th notes, with accent still emphasizing the original structure of the rhythm. Inbetween you have N “hits” of the instrument strategically distributed over the pattern under the genre constraint. It’s super easy to twist the knobs and make a pattern evolve with that.

Now this sounds like my kind of thing :wink:
Is it 1 device at a time? IE, Synth, or drum machine? Or can it do both simultaneously?
Seems great either way though! Well done :slight_smile:
Audio demos soon?

Seems like you have a winner here. :slight_smile: Very cool features!

Wow, I know where I’ll be dropping lots of cash this fall…

Updated post with link to audio demos. Yes, it’s a single device and it can do both. Drums are digital and MCU-generated ; Synth is analog with little CPU used whatsoever for it (except LFOs and envelopes).

anal eurorack question : is the audio out/synth out/drums out available on 3.5mm jack? Is it at 10v p2p?

Skynet built a CR-78…

I really like the audio demo’s! Thanks for posting them up so quick :slight_smile:
It sounds very nice to me. Some odd noise at about 2-30 in the first demo though? Like a crackling…
I realise this is still “Work in progress” of course though.
Im sure i’ll have to make me one of these… Who knows, maybe it will even persuade me to have a go at a modular rig too.

@fleetway: for now the drums and the synth are mixed. I might change that if there is enough board. FYI, I added the drum machine mode only on thursday and this was not really part of the original plan. Had to do something with the spare CPU cycles! I actually had to hack the board a bit because the drums are going through a PWM pin that was assigned to something else originally :smiley:

Anyway, this is certainly not 10v pp since the whole thing works internally at +/- 5V.

@Luap: Try the new demo links. The files are hosted on my server, and they were compressed with lame and reasonable settings. Soundcloud compresses at 96 kbps or whatever and this doesn’t work well with VCO rawness.

I see this as a wonderful addon to my x0xb0x.

Wow… In that case, what a great demonstration of how badly Soundcloud can fudge up an audio file! Your self hosted demos are much better, with none of that weird crackling I heard earlier.

I hope it is only some features rather than the core sound that changes once this thing is finalised. Im liking it quite a lot as it is!

The things that will change are (ideally all) the additions listed in the TODO list. Nothing removed, nothing going to sound differently.