A 2-operator FM synth — one carrier modulated by one operator. Great for metallic bells, e-piano, plucky basses, and digital pads. Switch a track to FM via the type chip; the bottom-panel FM tab shows the controls.

Knobs

• Ratio — modulator-to-carrier frequency ratio. Integer ratios (1:1, 2:1, 3:1) sound harmonic; non-integer ratios (1.41:1, 2.7:1) get clangy.
• Mod Index — how loud the modulator drives the carrier. Low = mild timbre, high = aggressive sidebands / metallic edge.
• Mod ADSR — independent envelope on the modulator, so you can sweep the timbre over the note (DX-7 era e-pianos all use this).
• Carrier ADSR — main amp envelope.