The Birth Of A New Synth – ShrutHi-1 Kit #000

This is a sneak preview of a new DIY synth project – the Mutable Instruments ShrutHI-1 digital/analog hybrid monosynth.

The video demonstrates some of the presets on ShrutHi-1 Kit #000.

Specs below. See the Mutable Instruments site for details. 

2 digital oscillators

  • band-limited sawtooth with adjustable phase
  • band-limited square wave with adjustable pulse-width
  • band-limited triangle wave with adjustable waveshapping
  • phase-distortion emulation of a low-pass filtered sawtooth (casio CZ-101)
  • phase-distortion emulation of a low-pass filtered sawtooth with high resonance (casio CZ-101)
  • phase-distortion emulation of a low-pass filtered sawtooth in the Rocker Launcher’s world in which sine waves are turned into triangles (casio CZ-101)
  • mysterious phase-distortion thing (could have been in the CZ-101 if the engineers at casio dared…)
  • phase-distortion emulation of a Jew’s harp / Morsing (could have been in the casio CZ-101)
  • stack of 4 detuned sawtooth waves (with aliasing)
  • simplistic FM (1>2 configuration), with adjustable modulation index and frequency ratio
  • wavetables, wavetables, wavetables!
    • sweepable table of basic waveforms
    • tampura transwave
    • PPG harsh creature
    • single cycle waveforms taken from D50 patches
    • cello transwave
    • slap bass transwave
    • organ/drawbars single cycle waveforms
    • male voice
    • user wavetable, can be edited by SysEx messages
  • 8bit-like harsh waveforms with wavetable scan
  • sine wave with variable amount of bitcrushing
  • poor man’s square with pulse-width modulation (plenty of aliasing but fat for basses)
  • colored noise (sweep from low-pass filtered white noise -> white noise -> high-pass filtered white noise)
  • lo-fi vowel synthesis (think “speak and spell”) with vowel morphing


  • adjustable oscillator balance
  • mixing algorithms: simple sum, simple sum with synchronization, ring modulator, xor modulator, sum with post-mixing tanh fuzz
  • extra sources: noise, sub-oscillator (triangle or square) or percussive attack generator (click, glitch, blow, metallic, pop)

Audio quality/resolution

  • Internal digital audio signal processing chain: 39062 Hz, 8 bits.
  • Internal digital control signals processing chain: 976 Hz, 8 bits.
  • Digital outputs: 10 MHz, 1 bit.


  • Exchangeable analog signal processing boards:
    • CEM3379: based on the CEM3379, uses the same circuit as the original Shruti-1 with the “click filtering” mod
    • SMR4: a 4-pole LPF (very SSM2044-like) and linear VCA built with the widely available LM13700 transconductance amplifier and TL074 op-amp
    • SSM2044: SSM2044 4-pole LPF, SSM2164 2-poles HPF + linear VCA.
    • (à suivre)


  • LFOs: 2, with square, sawtooth, triangle, sample & hold, and step sequencer shapes. Syncable to tempo. Adjustable “raise/attack” time. LFOs can be free-running, sync’ed to envelope retriggers, or retrigger envelopes.
  • envelopes 2 ADSR
  • modulation matrix: up to 12 source -> destination connections. Adjustable modulation amount in the -100% — 100% range
  • modulation sources:
    • LFO 1/2
    • step sequencer
    • first / second half of the step sequence
    • arpeggiator gate
    • mod. wheel
    • aftertouch
    • pitch bender
    • DC offset
    • CV inputs 1/2/3/4
    • MIDI CC 16 to 19
    • noise generator
    • env 1/2
    • random value resampled at each note on
    • note velocity
    • note number (eg for filter tracking)
    • keyboard gate
    • audio signal from the mixer output (decimated at 1kHz)
  • modulation destinations:
    • filter cutoff
    • VCA gain
    • pulse width/Parameter osc. 1/2
    • wide pitch osc. 1/2
    • pitch, applied to osc 1 & 2 simultaneously
    • very fine pitch, applied to osc 1 & 2 simultaneously
    • oscillator balance
    • noise level
    • subosc level
    • resonance
    • PWM CV output 1
    • PWM CV output 2
    • 2 bits digital value on CV output 1/2
    • LFO1 FM
    • LFO2 FM


Clock/tempo generator

  • internal clock: 40-240 BPM, with some additional extra fast tempi for effects (270, 300, 360, 480, 600, 720, 960)
  • external MIDI clock with divider
  • 6 groove templates (swing, shuffle, push, lag, human, monkey) with adjustable amount


  • 1-4 octave range
  • up, down, up&down, random
  • 15 preset rhythmic patterns + 1 programmable rhythmic pattern
  • warp: creates complex rhythms by cyclical repetitions of steps (eg 1212343456567878 instead of 12345678)
  • latch/hold


  • 16 steps, with legato/slide, velocity, and modulation
  • 4 modes corresponding to different interactions between the sequence and keyboard play: latch / transpose / loop recorder / override


  • custom page in which 4 user-selectable parameters can be assigned to the 4 editing pots
  • microtunings/key maps for arabic scales (1/4 tones) and a selection of hindustani ragas
  • portamento, legato on/off
  • master tune

System and memory

  • complete MIDI implementation, including patch editing by CC or NRPNs, patch and sequencer data transfer, full memory backup, wavetable transfer
  • MIDI out modes: off, thru, thru+knob movements sent as CC, sequencer/arpeggiator generated events only, polychaining, split (plays notes below split point, forwards the other notes)
  • patch memory: 80 patches and 80 sequences stored in EEPROM (no backup battery required)
  • firmware update by SysEx

Hardware and connectors

  • power: 2.1mm connector, requires 7.5V-9V 300mA supply (can be unregulated). Center pin positive (+), outer collar negative (-)
  • audio input/output: 6.35 Jack (Mono audio out), 6.35 Jack (External signal in)
  • cv inputs: up to 4 CV inputs for easy experimentation with controllers ( might not be broken out on analog VCF/VCA board )
  • cv outputs: up to 2 CV outputs ( might not be broken out on analog VCF/VCA board )
  • MIDI: in, out
  • serial: extra UART TX pin available on control panel board (might be used in future firmware updates to control extension boards)
  • ISP connector for firmware development
  • controllers:
    • 8 facade LEDs (current page / modulation matrix visualization)
    • 6 navigation switches
    • 4 pots for patch editing
    • clickable rotary encoder for fine parameter adjustment or navigation

      backlit 2×16 LCD display

5 thoughts on “The Birth Of A New Synth – ShrutHi-1 Kit #000

  1. I think I like this. Would be nice next to my mopho in the micro synth synth of my studio. It sounds like the noises that come from this thing are varied enough from the mopho. What do you think?

  2. Interesting. I got on the email list with the company, can't wait to find out pricing. By the way EATYone, I love that track you have at the end of your demo video above, really fresh. I like that west coast lead over the thick bass line. I wish there was more of community in Philly, USA (where I live) that could get together and demo songs/trade tips. In a perfect world. Do you have an album or tracks for download? Here is some music of mine. All of this stuff is mostly just me practicing various production techniques and messing around. I've just recently started putting in some serious time on new tracks because I am not touring at the moment.

  3. I don't get the appeal of the Monotron. Its so limited.

    This, however, I get!
    I would rather have one of these, than 2 or 3 monotrons (if I am guessing the price correctly).

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