This Ableton tutorial walks through all six Unison modes in the Wavetable synthesizer, explaining what each one does to the sound and why. Unison works by layering slightly detuned oscillators, which pushes sounds wider and deeper, and each mode takes a different approach to how that detuning is applied.
Classic spaces the oscillators evenly and pans them to alternating stereo channels. Shimmer adds random pitch jitter at slow intervals for a reverb-like shimmer, while Noise pushes that jitter much faster for a breathy, textured result. Both also apply a small Wavetable Offset for added fullness.
Phase Sync uses the same even detuning as Classic but locks the oscillator phases at note start, which produces a sweeping phaser-style sweep on each hit. Position Spread distributes each oscillator across different points in the wavetable rather than just detuning pitch, with a small detune added for width. Random Note randomizes both wavetable position and detune amount on every new note, giving you a different character each time a key is played.