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Eurorack Oscillators for Korg prologue, minilogue xd and Nu:tekt NTS-1

Ports of some of Mutable Instruments (tm) oscillators to the Korg "logue" multi-engine.

See releases for latest binaries.

Macro Oscillator 2 (based on Plaits)

Name Oscillator Shape operation Shift-shape operation
mo2_va Pair of classic waveforms Shape Pulse width
mo2_wsh Waveshaping oscillator Amount Waveform
mo2_fm Two operator FM Modulation index Frequency ratio
mo2_grn Granular formant oscillator Frequency ratio Formant frequency
mo2_add Harmonic oscillator Index of prominent harmonic Bump shape
mo2_wta* Wavetable: Additive (2x sine, quadratic, comb) Row index Column index
mo2_wtb* Wavetable: Additive (pair, triangle stack, 2x drawbar) Row index Column index
mo2_wtc* Wavetable: Formantish (trisaw, sawtri, burst, bandpass formant) Row index Column index
mo2_wtd* Wavetable: Formantish (formant, digi_formant, pulse, sine power) Row index Column index
mo2_wte* Wavetable: Braids (male, choir, digi, drone) Row index Column index
mo2_wtf* Wavetable: Braids (metal, fant, 2x unknown) Row index Column index
mo2_string Inharmonic string model Decay Brightness

* Due to the 32k size constraint in the multi-engine the Wavetable oscillator is split into 6 oscillators of 8 rows (scannable by Shape) by 4 columns (scannable by Shift-shape)

Parameters

In the Multi-engine menu you can find additional parameters for the oscillators.

Parameter 1 is oscillator specific and controls whichever parameter is not mapped to Shape or Shift-shape.

Parameter 2 sets the mix between the oscillator out and aux.

LFO Target sets the Shape LFO target, see list below.

LFO2 Rate is rate of LFO2.

LFO2 Int is intensity (depth) of LFO2.

LFO2 Target sets the target for LFO2 according to the list below.

LFO2

The oscillator has a built-in additional cosine key-synced LFO which can module an internal parameter (set with the LFO2 Target parameter in the oscillator menu):

LFO Target Parameter Notes
1 Shape
2 Shift-shape
3 Parameter 1 Not implemented for Wavetable oscillator
4 Parameter 2
5 Pitch
6 reserved (Amplitude?)
7 LFO2 Rate
8 LFO2 Int

For more information please read the excellent Mutable Instruments Plaits documentation.

Tips

Many parameters 'neutral' settings are in center position, such as va Detune or fm Feedback, however the prologue defaults all parameters to the lowest value, hence get used to going into the menus and set the first parameter to 50% when instantiating the oscillator.

Modal Resonator (based on Elements)

Physical modeling synthesis

Name Oscillator
mod s Strike exciter with modal resonator

Parameters

Parameter Parameter LFO Target Notes
Shape knob Resonator position 1 Position where the mallet strikes, has a comb-filtering effect.
Shift + Shape knob Resonator geometry 2 Geometry and stiffness of resonator. Set to 25-30% for a nice tuned sound.
Strength menu Strike strength 3 Mallet strength, high values causes the strike to bleed into the resonator output.
Mallet menu Strike mallet 4 Type of mallet, over 70% is bouncing particles.
Timbre menu Strike timbre 5 Brightness/speed of the excitation.
Damping menu Resonator damping 6 The rate of energy dissipation in the resonator. High values cause long release effect.
Brightness menu Resonator brightness 7 Muting of high frequencies
LFO Target menu multi-engine Shape LFO target Sets which parameter is modulated by the Shape LFO (see LFO Target column)

For more information please read the excellent Mutable Instruments Elements documentation.

Limitations

Due to compute and memory (32K!) limitations in the prologue multi-engine quite a few short-cuts had to be taken:

  • Only the Strike exciter is used
  • Sample-player and Granular sample-player mallet-modes did not fit in memory
  • Resonator filter bank is reduced to 24+2 filters from 52+8
  • Resonator filters are recomputed one per block instead all-ish every block
  • Samplerate is 24KHz vs 32KHz in Elements

Sounds pretty great IMO but go buy Elements for the real experience!

Tips

When you first select the oscillator it will make no sound, all parameters are at 0%! Increase the Strength and Damping parameters until you start hearing something.

Try a nice pluck:

Parameter Value
Shape 50%
Shift + Shape 30%
Strength 90%
Mallet 45%
Timbre 45%
Damping 70%
Brightness 45%

Issues

  • The prologue Sound Librarian tends to timeout when transferring the user oscillator, however the transfer is still complete. Try adding the user oscillator one at a time and Send All / Receive All for each oscillator.

  • There's been many reports that the Modal Resonator oscillator doesn't produce any sound. I've included a few versions which lower CPU usage which may yield better results. On my prologue there's been cases where I've had issues after a factory-reset where the oscillator wouldn't produce sound. Installing sequentially in the same oscillator slot the lightest CPU version osc_modal_strike_16_nolimit (16 filters and removed limiter), followed by osc_modal_strike_24_nolimit followed by osc_modal_strike resolved the issue for me. Your milage may vary.

  • When first selecting the oscillator in the multi-engine, all values default to their minimum values, however the display seems to default to 0. For bipolar values it means the display might still show 0% while internally in the oscillator the value is -100%.

Building

  • Checkout the repo (including subrepos)
  • Follow the toolchain installation instructions in the logue-sdk
  • Make sure you have the jq tool installed (brew install jq)
  • Build with make

(only tested on MacOSX)

Acknowledgements

All credit to Emilie Gillet for her amazing modules!