Ableton's own tutorial channel walks through every key parameter of the Phaser mode in the Phaser-Flanger device, using a raw saw wave pad as the demonstration sound throughout. The notch count controls how many frequency dips the effect carves into the signal, from a single subtle sweep all the way up to 42 stacked notches, while spread determines how far those notches sit from the centre frequency.
The LFO section drives automatic movement, with rate sync options ranging from slow eight-bar sweeps to fast 16th-note pulses, or a free frequency mode for movement that sits outside the grid. Feedback feeds the output back into the input to intensify the phasing character, and inverting the polarity shifts that character toward a hollower, more resonant quality.
Blend changes what the LFO actually modulates: at zero it moves the centre frequency, at one it moves the spread, creating a contracting and expanding notch pattern instead of a sweep. Dry/Wet sets the balance between the processed and original signal, and the Warmth control adds saturation and distortion at the output stage for a slightly dirtier result.