Eurorack Reference / modules /cosmotronic/messor audit site v0.1 — milestone 3
cosmotronic/messor

Messor

Cosmotronic

Stereo VCA-based feed-forward compressor and transient shaper with internal sidechain featuring switchable HP/LP filtering, precision envelope follower, attack/release/threshold/ratio/makeup gain controls, warm tube saturation mode, bypass switch, and CV inputs for key parameters.289

Capabilities 3

Stereo Compressorstereo-compressor
VCA-based feed-forward stereo compressor with internal sidechain featuring switchable HP/LP filter, precision envelope follower, and controls for attack, release, threshold, ratio, and makeup gain.289
Stereo VCAstereo-vca
Set Make Up knob to MUTE and patch an envelope to the GAIN CV input to use as a stereo VCA. Nominal CV range 0–5V.289
Transient Shapertransient-shaper
Ratio can be pushed past limiting into over-compression to completely reshape transients for sound design.289

Jacks 10 — 7 in / 3 out

NameSignalVoltageDescription
Inputs (7)
JaudioExternal sidechain input. Normalised to a mono mix of the left and right channels. Patching in breaks the normalisation and routes the external signal to the sidechain.289
Kcv0V to 5VGain CV input. Modulates the makeup gain/output level. With MAKE UP knob at MUTE, turns Messor into a stereo VCA.289
LaudioLeft audio input. Normalised to the Right input when nothing is patched into it.289
Mcv0V to 5VAttack CV input. Modulates the attack time; Attack knob acts as offset.289
Ncv0V to 5VRelease CV input. Modulates the release time; Release knob acts as offset. Negative CV can push release below 5ms.289
OcvSidechain filter cutoff CV input.289
PaudioRight audio input.289
Outputs (3)
QcvSidechain envelope output. Available independent of Ratio and Bypass switch settings.289
RaudioLeft audio output.289
SaudioRight audio output.289

Parameters 9

NameTypeRangeBehavior
Aknob289
BknobSets the time the compressor takes to start reducing output volume; controls how much of the initial transient is preserved and how fast compression kicks in. Longer settings average out dynamics. Attack knob works as an offset for the ATK CV input.289
Cknob5ms – 3500msSets the release time of the gain reduction envelope. Longer times create an averaging effect. Very short release times can create distortion in low frequencies. Release knob works as an offset for the REL CV input. Negative CV can push release below 5ms.289
DknobSets the threshold level where compression kicks in. Signals below the threshold are ignored; signals above generate the sidechain. Lower threshold settings create more gain reduction. Module expects modular levels (-10 to 17dBv). Gain reduction envelope is visualised by orange LEDs under the knob.289
EknobApplies gain to the signal after compression to match output level to input level. Acts as an offset for the GAIN CV input. Set to MUTE with envelope patched to CV input to use Messor as a stereo VCA.289
FknobSets the cutoff frequency of the internal sidechain filter (6dB/oct, switchable LP/HP). Determines which frequencies trigger gain reduction. Can be set to cut off all frequencies, disabling compression entirely.289
GswitchSelects the sidechain filter mode: Low-Pass or High-Pass (6dB/oct). HP mode with cutoff at 300Hz filters out low frequencies such as kick drums.289
HswitchSwitches between Pure and Warm modes. Warm enables analog tube saturation emulation that soft-clips signal as headroom limit approaches, adding extra compression and warmth while leaving lower-level signals intact. A side effect is slightly lower output volume.289
IswitchBypasses the compressor. The SC Envelope Output (Q) remains active when bypassed.289

Firmware history 0 versions

No firmware history recorded.

References 2

  1. [289]
    Cosmotronic Messor Manualmanual
    verified 2026-05-08
  2. [290]
    Cosmotronic Messor product pageproduct_page
    verified 2026-05-08