This section of Ableton's Tree Tone walkthrough covers the Tuning controls that shape how the device's resonators relate to each other musically. The Spread parameter sets how far apart the resonators' frequencies are distributed, from tightly clustered to broadly spread across a wide range.
Scale quantizes all resonator frequencies to a chosen key, which immediately makes the output sound more tonal and harmonic. The root note is adjustable by dragging, and shifting resonators to different scale degrees creates chord-like voicings within that key.
The Harmonic control gradually returns the resonators to their unquantized, raw frequencies, useful when you want to dial back the musical effect without losing it entirely. Available scales include Pentatonic, Phrygian, and Diminished, and the device also accepts custom Scaler files for microtonal tuning. In that case, the Tonic parameter becomes an Offset expressed as a ratio, so a value of 2:1 raises the root note by an octave.