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Tuning and Calibration

Folks that purchased fully-built WaveBoys should not need to tune it unless you have lost your adc1cal.txt and tuning.txt files. If you did, contact us as we may have your original settings on file.

First I apologize for the lack of example images for the UI. This is brand new and still may be subject to tweaks and things.

The assembled versions of WaveBoy will come pre-calibrated. DIY versions or updated firmware may change the tuning which may require adjustments. This can be done by going to the Tuning option under the Config menu.

As of 0.54, each note can be individually tuned. This was to allow for precise tuning even when there are variances within each note across the ADC range. Future WaveBoy PCB updates might not require this level of precision, but the approach is flexible, if a bit tedious initially.

Pre-requisites

To tune the WaveBoy, you will need a means to generate good V/Oct values for notes. You will also need an accurate tuner.

When tuning assembled WaveBoys, we use Ableton live's built-in tuner along with the MutantBrain MIDI to CV module and uO_C (for generating specific voltages and as a secondary tuner).

When doing a full calibration, you need to find a stable and good voltage source that can generate 0.75V and 4.25V reliably (such as an already-calibrated uO_C or similar module).

The display shows several values.

  • Press the left knob to enable/disable the pitch knob
  • Press and hold the left knob to exit the Tuning module, noting changes are not automatically saved and the pitch knob may end up disabled. Easiest way to fix that is to power-cycle the module or press the reset button on the back.
  • Press the right knob to toggle the large display readout (from steps-per-note to max ADC)
  • Press and hold the right knob to save the settings.
  • Turning the left knob selects the note being tuned.
  • Turning the right knob adjusts the SPN or Max ADC value, depending on which one is selected.

The bottom 4 lines are information about the incoming note being read from V/Oct.

  • Note ADC Top: Max ADC value of selected note
  • Raw ADC is the equivalent value from the analog-to-digital converter.
  • Est. Pitch is the calculated pitch value (this should closely match what your tuner says)
  • Note is the equivalent MIDI note value for the calculated pitch.

Tuning Adjustments

If you are making minor changes to the tuning, these steps are usually sufficient if the WaveBoy isn't wildly off-tune.

  1. Press the left knob to enable the pitch knob if not already.
  2. Out a note in the middle of range, say C-4, and adjust the pitch knob until it is tuned.
  3. Run through the pitch range and see how the values deviate, note the ones that might be off by a significant amount. If you find the note you picked to tune from itself is an outlier, pick another note and try again.
  4. Once you have the outliers, you can then select them on the WB, send that note value to the WB and then adjust the steps-per-note (the decimal value) until it's tuned. If you find the output pitch isn't being adjusted, press the right knob to go the ADC setting and make sure that the ADC value is above the Raw ADC value. Usually it should be above the Raw ADC value by around 5-10.
  5. Press the right knob to go back to steps-per-note to tune the note.
  6. If it still doesn't work, the ADC value of the previous note might be high enough it is being read first, so you will need to adjust that notes ADC in the same way (by playing that note, and setting the ADC to 5-10 above the Raw ADC value).
  7. Try all that again for the note you want to tune.
  8. Do this for all the notes that you want to adjust.
  9. VERY IMPORTANT! Once done, press and hold the right knob to save the settings.

Full tuning procedure

This is akin to tuning a newly built WaveBoy end to end. It includes an optional, but recommended, step of calibrating the ADC1. This makes the actual calibration process a little more consistent.

Optional ADC Calibration

This is an option pre-calibration step which makes the tuning values between each WaveBoy closer to each other. It's not needed, but can be helpful and may give you better overall tracking performance.

  1. Remove the SD card from the WaveBoy, mount it and rename the adc1cal.txt file to something else (say adc1cal.bak). This skips the internal ADC calibration on power-up.
  2. Reinsert the SD card into the WaveBoy and power up the module from your Modular supply (not from USB).
  3. Go to the Tuning menu, and then send 0.75V to V/Oct and write down the Raw ADC value.
  4. Do the same for 4.25V.
  5. Go to Stargirl's SAMD21 ADC page here and scroll down to the "Offset & gain error correction" calculator and put in the following values:
    1. Max Input Voltage: 5
    2. Low Side Input Voltage: 0.75
    3. Low Side Measured ADC Code: (0.75 Raw ADC value you wrote down)
    4. High Size Input Voltage: 4.25
    5. High Side Measured ADC Code: (4.25 Raw ADC value you wrote down)
  6. Remove the SD card from the WaveBoy again. Copy the adc1cal.bak file to adc1cal.txt and then edit the file, replacing the Offset and Gain error values with ones from the calculator.
  7. Reinsert the SD card into the WaveBoy and power-cycle it.

Full tuning/tracking calibration

  1. Make sure the WaveBoy is in Wave mode. Pick a clean patch (like the Sine patch).
  2. Go to the tuning menu.
  3. When in the Tuning menu, press the right knob to disable the pitch knob.
  4. For each note from D-2 to C#7:
    1. Send the V/Oct for the note into the V/Oct on the WaveBoy and use the output from the WaveBoy into a known
      accurate tuner.
    2. Use the left knob to select the note being tuned. Use the right knob to first pick the Max ADC value. Check that this value is somewhat above the "Raw ADC" value, typically by 5-10. So if the Raw ADC is 270, set the Max ADC to 280.
    3. Press the right knob to bring up the Steps-Per-Note. While looking at your tuning, adjust this value until the note is within your acceptable tuning range. Note that at the high extreme you may not be able to get it perfect. Also note that the faster you turn the knob, the more coarse the tuning. Once you get close to in-tune, turn the knob more slowly for precise tuning.
    4. If you have trouble getting it right on, consider tuning towards the sharp side.
    5. Typically after tuning one full octave, press and hole the right knob to save your settings just in case.
    6. Go to the next note and repeat. Note that C#7 doesn't always work.
  5. Once all notes have been tuned, run through the entire note range to make sure all is well.
  6. If it is, press and hole the right knob to save your settings.
  7. Now press the left knob to enable the pitch knob. Adjust the knob choosing a base value other than concert tuning. For instance, tune C-4 to A-4 and re-run through the note range (noting the offset). Tuning should be mostly the same. It may not be perfect but should be acceptable.
  8. If it is, congrats! Be sure to save your settings (press and hold the right knob). Then exit the Tuning menu and power-cycle the WaveBoy. Give it one final once over and if it's tracking acceptably, you're all done!
  9. Be sure to backup both the tuning.txt and adc1cal.txt files in a safe place!