This walkthrough breaks down the Operators tab in Ableton's Vector FM synthesizer, showing how the number of active Operators changes the entire FM algorithm. With a single Operator enabled, the Carrier modulates itself based on Ratio and Index settings, and setting Index to zero turns Vector FM into a straightforward subtractive synth using its built-in multimode filter.
Activate two or more Operators and the behavior shifts: each new MIDI note adds a new Operator instead of a new voice. The first note becomes a sine wave Carrier, the second frequency modulates it, the third starts a fresh Carrier, and so on, with lines in the 2D particle display showing exactly which particles are modulating which.
The video doesn't dig into every algorithm configuration in depth, but it gives enough to start experimenting: switch between Operator counts, watch how the particle connections change, and get a feel for how note order builds out your FM chain before moving on to the Audio Parameters tab.