oxi-instruments/coral

Coral

OXI Instruments

8-Voice polyphonic, multitimbral Stereo Eurorack Module with 13 synth engines, MIDI and CV inputs, built-in filter, amp and filter envelopes, reverb, delay, chorus, WAV player, and MPE support.637

Capabilities 5

MIDI Inputmidi-input
637
MPE Supportmpe-support
MPE enabled via options.txt (mpeena 1). Aftertouch mapped to filter cutoff and volume. Slide and other expressive dimensions assignable to CC parameters.637
Multitimbralmultitimbral
Each of the 8 voices can have a different engine, MIDI channel, and independent parameter set, grouped into parts.637
Polyphonic Synthesizerpolyphonic-synth
Up to 8 simultaneous voices, configurable into parts, each voice independently assigned to any of the available synthesis engines.637
Sample Playbacksample-playback
WAV Player engine supports mono/stereo samples at 16/24/32-bit, 44.1/48kHz, organized in up to 10 folders of 32 samples each. Polyphonic one-shot playback.637

Jacks 12 (10 in / 2 out)

NameSignalVoltageDescription
Inputs (10)
MIDI TRSmixed—MIDI TRS input, compatible with both Type A and Type B wiring standards.637
amp CVcv-5V to 5V637
atkdec CVcv-5V to 5VIncreases or decreases the duration of attack, decay and release of both AMP and MOD ADSR envelopes. Negative voltages make the sound pluckier; positive voltages create softer and longer sounds.637
filter CVcv-5V to 5VPositive voltages increase the filter frequency cutoff; negative voltages decrease it.637
harm CVcv-5V to 5V637
morph CVcv-5V to 5V637
oct CVcv—CV/Oct pitch input. The oct and freq knob parameters are combined with this input to determine the final pitch of the voices.637
part CVcv0V to 5VSelects which part is affected by CV modulation (0–5V range divided equally across parts). Can alternatively be configured to select the active engine instead.637
timbre CVcv-5V to 5V637
triggate—Triggers the internal envelopes. Triggers all voices of the selected part.637
Outputs (2)
OUT Laudio-5V to 5V637
OUT Raudio-5V to 5V637

Parameters 19

NameTypeRangeBehavior
amp atkknob—Sets the attack time of the amplifier ADSR envelope.637
amp drknob—Sets the time of the Decay and Release stages of the amplifier ADSR envelope.637
chorusknob—Secondary parameter. Sets the send amount to the Chorus FX engine. If the High Pass Filter is enabled in options.txt, this control sets the HP filter frequency instead (one per voice).637
f.envknob-100% – 100%Sets the amount of the MOD ADSR envelope applied to the filter frequency. Bipolar: at 12 o'clock it is 0%, fully CW is 100%, fully CCW is -100%.637
f.resoknob—Sets the resonance and drive of the filter.637
filterknob—Sets the cutoff frequency of the low pass filter.637
freqknob-100% – 100%Secondary parameter. Fine control of the base frequency. At 12 o'clock there is no detuning. Bipolar: fully CW is 100%, fully CCW is -100%.637
harmknob—Controls the first parameter of the selected engine. In the case of the Wav Player, it acts as an overdrive control.637
levelknob—Secondary parameter. Sets the maximum amplitude level of the voice.637
midiknob—Secondary parameter (of the harm knob). Selects the MIDI channel for the selected voice or part.637
mod atkknob—Sets the attack time of the modulation ADSR envelope.637
mod drknob—Sets the time of the Decay and Release stages of the modulation ADSR envelope.637
morphknob—Third parameter of the engine. In the Wav Player engine, selects the sample folder.637
Zones
fm
Chaotic
Rough
  • Chaotic -100–0%Operator 2 modulates operator 1's phase — chaotic character.637
  • Rough 0–100%Operator 2 modulates its own phase — rough character.637
noiseknob—Secondary parameter. Controls the level of the white noise internal source. Not affected by the voice level, providing an independent noise source. If Delay is enabled, this control instead sets the delay send amount.637
octknob—Sets the base octave of the sound. Acts as an offset of the input MIDI note or CV pitch input.637
panknob—Secondary parameter. Sets the stereo pan using a constant power pan law.637
spaceknob—Secondary parameter. Sets the send amount to the Space (reverb) FX engine.637
sustknob—Sets the sustain level of both the amplifier and the modulation ADSR envelopes.637
timbreknob—Second parameter of the engine. In the Wav Player engine, selects the sample.637

Firmware history 2 versions

VersionReleasedNotes
2.12025-01-20637
0.7.0—Folders and samples in the WAV Player are now alphabetically ordered.637

References 2

  1. [637]
    OXI Coral User Manualmanual
    source 637 canonical ↗ archived ↗
    ● verified 2026-05-21
  2. [638]
    OXI Coral product pageproduct_page
    source 638 canonical ↗ archived ↗
    ⚠ verified 2026-05-21 · manufacturer changed since last verified