FM4 Filter Modeler

The purple pedal in Line 6's original stompbox modeler series focused on filters and synthesis effects. Envelope followers, auto-wahs, talk box simulation, ring modulator, and synth-like tones fill the 16 model slots.

Four knobs adjust effect-specific parameters. Three user presets store settings. Expression pedal input enables real-time filter sweeps.

Less common on pedalboards than the DL4 or MM4, but invaluable for players exploring synth textures and filter effects without dedicated hardware.