CV Tuner
User guideOverview
Firmware for calibrating Brain outputs with a tuner-guided workflow. It lets you calibrate channel A and B across 0V..10V in 1V steps for precise 1V/oct tracking. The calibration values are saved to the Brain module and guaranteed to persist across official Shmøergh firmwares, meaning you'll only need to calibrate once.
How to calibrate
Prerequisites
To calibrate the CV outputs you'll need:
- Brain module running this firmware
- A precisely tuned VCO — can be the VCO's in the Moduleur or any Eurorack VCO with a coarse and fine tune knob, tuned to
1V/octpitch tracking - A tuner (hardware tuner or tuner plugin/app)
- Patch cable from Brain CV out to the VCO pitch input
Prepare your synth setup following these steps:
- Make sure there's nothing patched to your VCO's pitch input
- Connect the output of your VCO to your tuner
- Tune the VCO to
C0(16.35Hz) using the coarse/octave and fine knobs. (If your tuner can't pick up this low frequency then you can tune for `C1 but in this case you won't be able to calibrate the full range of the Brain outputs)
Calibration process
Controls
| Function | What it does |
|---|---|
| Button A | Step down 1V (10 -> 0) |
| Button B | Step up 1V (0 -> 10V) |
| Hold Button A for ~1s | Switch output channel |
| Hold Button A + B for ~1s | Save calibration value |
| Pot X | Coarse tuning offset |
| Pot Y | Fine tuning offset |
You can calibrate each output of Brain module with the same method. By default the firmware is set to tune Out 1 , you can switch channels by holding Button A for about 1sec.
During the tuning process the selected output channel will product whole voltages from 0V..10V (0V, 1V, 2V etc.), with 0V by default.
To tune the selected output channel:
- Start with the output generating
0V - Connect the output to the VCO
1V/octpitch input. Leave the tuner connected to the VCO audio output. - Use
Pot XandPot Yto tune the output to C note - Step up to the next whole voltage (e.g.
0V->1V) - Go to step 3
- Once you tuned all whole voltages, hold
Button AandButton Bto save the calibration values
LED feedback
| Feedback | What it means | Details |
|---|---|---|
| LED 1 | Out 1 active | |
| LED 2 | Out 2 active | |
| LED 3 | Unsaved settings (dirty) | |
| LED 4 | Save result | Success: 2 long pulses Failure: 4 short pulses |
| LED 5 | Storage protection | Solid on: protected save allowed Blinking: save blocked |
| LED 6 | Current voltage | Step 1..10: that many short pulses Step 0: one long pulse |
Save and Persistence
Calibration is saved only when you perform the explicit A+B hold. Saved values persist across power cycles and firmware updates (as long as calibration storage is preserved). If save fails, LED4 shows failure pulses and LED3 remains on.
Using a multimeter instead of VCO
Alternatively you can use a multimeter to measure the outputs instead of a tuner and a VCO. Just connect it to the selected output channel and use Pot X and Pot Y to calibrate the output voltage to whole voltages (0V..10V).