The function of the buttons depends on the type of effect selected:
|Tron Down||Frequency||Width||Range: Low/High||Low/Band/High-pass|
|Tron Up||Frequency||Width||Range: Low/High||Low/Band/High-pass|
|Seeker||Patterns||Width||Speed||Number of Steps in Sequence (2–9)|
|Voice Box||Start Vowel||Stop Vowel||Speed||Automatic/Pedal|
|V-Tron||Start Vowel||Stop Vowel||Attack Time||Up/Up & Return|
|Throbber||Frequency||Width||Speed||Ramp Up/Ramp Down/Triangle/Square|
|Spin Cycle||Frequency||Width||Speed||Speed Sensitivity to Input Volume|
|Slow Filter||Frequency||Width||Attack Time||Up/Down|
|Octisynth||Content||Width||Vibrato Speed||Vibrato Depth|
|Attack Synth||Frequency||Waveform||Attack Time||Pitch|
|Synth String||Frequency||Attack Time||Modulation Speed||Pitch|
Offering an awesome collection of vintage filter and monophonic synth effects, 24-bit processing, and true bypass, the FM4 features 16 models of classic and collectible filters and synths. With four programmable presets, the FM4 gives guitarists easy access to a set of world-class tones and controls for customization.
- 4 completely programmable presets available at the tap of a toe. No more need for multiple pedals for multiple effects.
- True Bypass switching, so your direct tone is exactly that; direct from your guitar to your amp.
- Expression Pedal Input - for real time control of all effect settings. Also the ability to morph between settings lets you create effects not possible with the originals.
- Nothing but knobs. No menus, no multiple button contortionist gymnastic moves, just twist and go.
- Stereo inputs and outputs
- Runs from batteries (Heck, we even include a set) or optional power adapter.
Tired of the same old effects? You say you want something a little bit... different? The FM4 Filter Modeler, part of Line 6's award winning line of Stompbox Modelers, gives you an array of vintage and new effects from just a wee bit odd to full frontal freaky! From the gentle auto-wah of an envelope filter to the complete wackiness of mutated VCO controlled ring modulators, FM4 can get as strange as you wanna be.
- (2008-11-14) Line 6 FM4 Filter Modeler: Change Your Filter Models Often by GearWire
- (2009-11-26) Bobby DeVito plays with the Line 6 M9 filters and other FM4 models by Bobby DeVito
- (2010-01-25) Line 6 FM4 Filter Modulator Demonstration Finale by GearWire
- (2010-07-08) FM4 Filter Modeler Overview | Line 6 by Line 6
- (2011-03-08) Line 6 FM-4 Double preset mod + footswitch upgrade by Tatosian Custom Effects
- (2011-03-26) Line 6 FM4 Filter Modeler Has A Spin Cycle You Won't Leave Alone by GearWire
- (2011-04-15) Line 6 FM4 Filter Modeler with Mods by Tatosian Custom Effects
- (2012-09-23) Line 6 FM4 Review by kaputsport
- (2016-05-12) Line 6 FM4 Filter Modeler by reverbmarket