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Tuning and Calibration

The assembled versions of WaveBoy will come pre-calibrated. DIY versions or updated firmware may change the tuning which may require adjustments.

If your firmware predates 0.65, and you do not want to upgrade, you will need to use this process instead:

Pre-0.64 Tuning Process

Instructional Video

The production value is not amazing but it at least shows how to do what is explained below.

Pre-requisites

To tune the WaveBoy, you will need a means to generate good V/Oct values for notes. You will also may need an accurate tuner, though this is no longer strictly required. It is generally easier to use a MIDI to CV interface for sending known correct CV V/Oct values to the WaveBoy though it can be done using other modules too. Just be sure it is accurately sending the correct note and octave (e.g. F-2).

Pre-assembled WaveBoys are tuned using a Mutant Brain MIDI interface with the tuning in Ableton Live and Renoise for sending the MIDI note to Mutant Brain. uO_C is also used to validate 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).

Display

The display shows 3 main pieces of information:

  • The current note being configured is at the top in larger font.
  • The 2nd row shows the Current ADC value. This is what is being read from the V/Oct input plus the tuning adjustment.
  • The 3rd row shows the ideal ADC value for the current note.

The display updates automatically once per second or when a knob is turned.

  • Press the left knob to save settings
  • Press and hold the left knob to save settings and exit the Tuning module.
  • Press the right knob to auto-calibrate the ADC values (see below)
  • Turning the left knob selects the note being tuned.
  • Turning the right knob manually adjusts the Current ADC value

Tuning Process

During the tuning process, the tune knob is disabled (to avoid skewing the results) meaning the note displayed (e.g. F-2) is the equivalent MIDI note you should be sending to the WaveBoy's V/Oct. This is important because the tuning process compares the ideal values of the current note with what is being read over V/Oct. Playing the wrong note will substantially impact these values.

  1. Backup your SD card (just in case)
  2. Make sure alt audio output is disabled (Step Output) and Vol Audio is off (Audo Options)
  3. Use the left knob to dial in the note. If running a full calibration, start at C-2.
  4. Play that note through V/Oct. The current value will update to the raw ADC value plus the tuning offset (if one is already set). C-2 is a special case where the ideal value will be zero. For all the other notes, it will be non-zero.
  5. To perform an auto-tune, simply press the right knob. This automatically reads the incoming raw V/Oct ADC value and sets the tuning adjustment for that note so that it matches the ideal value.
    1. If you want more accuracy, you can set the tuning adjustment manually.
    2. To do this you will need an external tuner. Instead of pressing the right knob, simply turn it left or right to adjust the value until it is in tune.
    3. Note this method may improve accuracy but it has not been well tested. The auto-tuning generally works quite well - far better than WaveBoy firmware versions prior to 0.65.
  6. Turn the left knob to go to the next note and repeat the process up to B-6.
  7. Save the settings by pressing the left knob.
    1. If you do not want to save the settings, you can power-cycle the WaveBoy to exit the config menu.

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.