STMix

Befaco 6HP
MIXER UTILITY

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Four-channel stereo mixer in 6HP. Per-channel attenuator with L-to-R mono normalization · unattenuated stereo AUX post-fader input · DC-coupled for CV mixing · rear header chains to Hexmix master.

Patch Ideas · 5

★ Four mono voices into stereo
Four mono VCOs → CH1-CH4 L(M) inputs, R jacks empty · each channel auto-upmixes to centred stereo · fader per voice · OUT L/R → master out · dense four-voice centre mix with one cable per voice
▸ Show diagram
Patch diagramPatch diagram with 7 modules and 6 connections. Signals: 6 audio.STMixVCO 1VCO 2VCO 3VCO 4STMix (LOutputCH 1-4: Level to tasteOUT LaudioOUT RaudioOutaudioOutaudioOutaudioOutaudioM) IN 1audioM) IN 2audioM) IN 3audioM) IN 4audioLaudioRaudioaudio
★ Stereo FX in, dry on AUX
CH1-CH3 feed voices into the mix · CH4 stereo = wet return from a reverb send · dry sum of the voices → AUX L/R to sit at unity behind the wet channel · fade CH4 to dial wet/dry without touching the voices
▸ Show diagram
Patch diagramPatch diagram with 7 modules and 9 connections. Signals: 9 audio.STMixVCO 1VCO 2VCO 3ReverbMultSTMix (LCH 1-3: voicesCH 4: wet returnR IN 4audioAUX LaudioAUX RaudioOutaudioOutaudioOutaudioIn LaudioIn RaudioOut LaudioOut RaudioSum LaudioSum RaudioM) IN 1audioM) IN 2audioM) IN 3audioM) IN 4audio121. dry send2. dry unityaudio
★ CV summing bus
Four modulation sources (LFO, envelope, random, offset) → CH1-CH4 L(M) · faders scale each contribution · OUT L = composite CV · because inputs are DC-coupled, STMix doubles as a 4-into-1 CV mixer with per-source level and unity AUX for a fifth signal
▸ Show diagram
Patch diagramPatch diagram with 8 modules and 6 connections. Signals: 6 cv.STMixLFOEnvelopeRandomOffsetExtra CVSTMix (LFilterCH 1-4: Level = mix amount per sourceAUX LcvOUT LcvOutcvOutcvOutcvOutcvOutcvM) IN 1cvM) IN 2cvM) IN 3cvM) IN 4cvCutoffcv121. unity2. composite CVcv
Chain two STMix for 8 stereo channels
STMix A inputs host voices 1-4 · STMix A OUT L/R → STMix B AUX L/R (unity, post-fader safe) · STMix B hosts voices 5-8 on its channels · STMix B OUT = full 8-channel stereo sum · no master fader loss on either bank
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 4 connections. Modules: STMix A, STMix B, Output. Signals: 4 audio.STMix ASTMix BOutputCH 1-4: voices 1-4CH 1-4: voices 5-8OUT LaudioOUT RaudioAUX LaudioAUX RaudioOUT LaudioOUT RaudioLaudioRaudio121. unity cascade2. 8-channel sumaudio
Drum submix to Hexmix
Kick, snare, hat, clap on CH1-CH4 (use R for stereo hats/claps) · rear ribbon → Hexmix master section · drum bus folds into Hexmix without burning channels there · front OUT L/R stay free for a separate monitor feed
▸ Show diagram
Patch diagramPatch diagram with 9 modules and 8 connections. Signals: 8 audio.STMixKickSnareHat LHat RClap LClap RSTMix (LMonitorCH 1-4: drum levelsR IN 3audioR IN 4audioOUT LaudioOUT RaudioOutaudioOutaudioOutaudioOutaudioOutaudioOutaudioM) IN 1audioM) IN 2audioM) IN 3audioM) IN 4audioLaudioRaudio121. stereo hats2. front-panel monitoraudio

Behaviors

Mono-to-stereo upmix per channel L(M) IN patched with the matching R IN unpatched

Each channel's L jack normalizes to its R when R is empty, so mono voices land centred in the stereo image. Patching R on any channel leaves that channel true-stereo while neighbours still upmix mono.

Unattenuated AUX post-fader signal patched to AUX L / AUX R

The AUX pair bypasses every channel fader and sums straight into the output bus at unity. Use for a fifth input, a chain-in from another STMix or a dry return that must not be attenuated by a misplaced fader.

DC-coupled CV mixing patching CV or offsets into channel inputs

All inputs are DC coupled, so STMix works as a 4+1 CV summer with attenuation per input. Mix LFOs, envelopes and offsets at any rate; the AUX pair adds two more unity-gain summing jacks on top.

Hexmix submix expansion 2×3 ribbon cable from STMix rear header to Hexmix

The rear six-pin header taps the STMix stereo sum into the Hexmix master section. Keeps the front-panel OUT jacks free while STMix acts as a dedicated four-channel stereo subgroup feeding the Hexmix bus.

Clip LEDs on the output sum approaching headroom

Red LEDs on OUT L and OUT R indicate signal presence and clip. Use them to back off individual channel faders until peaks stop reddening — needed because there is no master level on STMix itself.

No master fader using STMix standalone

STMix has only per-channel attenuators, no overall gain. Set final listening level downstream (OUT module, interface) or via the channel faders themselves. Chain into Hexmix when a master is needed.

Controls

CH 1-4 Channel Level Manual attenuator for each stereo channel pair. Controls both L and R of the channel together.
0 to unity · linear taper

I/O

IN · 4

  • L(M) IN 1-4 ±10V modular
    Left / mono input per channel. When R of the same channel is unpatched the L signal is duplicated onto R, so mono sources mix into the stereo bus.
    NORM → routed to the same channel's R bus when R IN is unpatched
  • R IN 1-4 ±10V modular
    Right input per channel. Patching R breaks the L-to-R normalization on that channel, giving true stereo.
  • AUX L ±10V modular
    Stereo auxiliary input, left side. Sums straight to the L output bus with no attenuation and after the channel faders.
    NORM → routed to AUX R bus when AUX R is unpatched
  • AUX R ±10V modular
    Stereo auxiliary input, right side. Sums straight to the R output bus with no attenuation.

OUT · 2

  • OUT L ±10V modular
    Left channel of the stereo mix sum. Clip LED lights on signal and reddens near headroom.
  • OUT R ±10V modular
    Right channel of the stereo mix sum. Clip LED lights on signal and reddens near headroom.