Description
The Mu-tron® Bi-Phase; the Korg® X911 Guitar Synth—are these rebel fighter ships from The Empire Strikes Back? Or maybe proton thrusters from outtakes of Babylon 5? Nope. These, and the other 13 techy tone temptations loaded into Line 6’s galactic-purple FM4 Filter Modeler stompbox, represent the outer limits of guitar filter effects, a territory many consider to be today’s most fertile terrain for discovering new sounds, timbres and tone colors.
In looking forward, Line 6 first looked back, to the filters, vocoders and guitar synths that players from Frank Zappa and Ernie Isley to Robert Fripp and Peter Frampton have made synonymous with creative guitar playing. “The Throbber” will have your tone gurgling with synth-approved LFO from four wave shapes, including square or triangle waves; “Tron Up/Tron Down” literally drips with auto-wah style response in either Low-, Band- or High-Pass varieties; “Synth-O-Matic” simulates the notably nasty filter sections and wave shapes of prized vintage synths from the Prophet® 600 to the legendary Arp Explorer.
Of course, you already use a filter effect all the time; every Wah-Wah pedal is a variable filter, and the FM4 includes a superb “Q Filter” that allows you find and fix that golden frequency notch, in the same spirit as “parked wah” practitioners like Queen’s Brian May and soul superstar Prince. Want to make it a more traditional wah? Just hook up the optional EX-1 expression pedal, and save a “Q Filter” sound to both a low frequency (heel down on the EX-1) and a high frequency (toe down on the EX-1) and you’ve got a more versatile wah than any off-the-shelf pedal, not to mention a pristine 24-bit signal path, stereo ins and outs, and true bypass switching.
Like all Line 6 stompbox Modelers, the FM4 boasts a simple and sturdy front panel design, with four footswitches for saving and recalling your sounds, and six knobs for selecting models and tweaking parameters, with distinct assignments for each knob depending on the model you’ve chosen. The Line 6 FM4 is for the true explorer of new sonic galaxies; expect to be surprised, stimulated and encouraged to absolute synth-fulness...
Available Models:
- Tron Down
- Tron Up
- Seeker
- Obi-Wah
- Voice Box
- V-Tron
- Throbber
- Spin Cycle
- Comet Trails
- Slow Filter
- Octisynth
- Synth-O-Matic
- Attack Synth
- Synth String
- Growler
- Q Filter
Bypass | true bypass |
---|---|
Analog/Digital | digital |
Power | 9V, AC |
2 AVAILABLE FROM


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John Frusciante's Line 6 FM4 Filter Modeler Guitar Effects Pedal was originally submitted to Equipboard without proof. If you can find a ... more

Used on *St. Anger*, as is visible in the first photo in the gallery [Jump in the Studio (The Making of *St. Anger*)](https://www.metalli... more

At 3:27 in this video reviewing Chris Wolstenholme's bass setup, we can see a Line 6 FM4 Filter Modeler Guitar Effects Pedal. more

"We've got the Line 6 doing the job of all the weird synth experimentation that came from a lot of Chili Pepper songs… This one is for a ... more

In this detailed breakdown of Chancellor's pedalboard, the Line 6 FM4 Filter Modeler is visible. more

This photo taken by Graeme Flegenheimer of Buckethead and his pedalboard reveals Buckethead uses a Line 6 LM4 Modulation Guitar Effects P... more
Reviews
Trusted musician and artist reviews for Line 6 FM4 Filter Modeler
Based on 9 Reviews

Sold it and have been regretting it since.
This pedal is nothing short of awesome. You can get super crazy digital filter tones from it or tame it down to a smooth LP.
Removed one star for those super awful footswitches on all these Line 6 products. Didn't learn my lesson though since I got the DL4 and an M13 after that, both which have the same footswitches.
This pedal was used by many professional musicians on tour and in the studio, if you can get your hands on one for a good price, don't think twice!

Filters and bleep-bloops and all that stuff.
Ok, you'll need a pedalboard almost only for this pedal. And some time home learning how to get decent sounds out of it. And a band who loves you for who you are, that won't bother you with silly questions like "why don't you buy a synth instead?" or "is it supposed to be this horr... ehm, peculiar?". Yes, it's supposed to, bitches! As long as you stay on the left side of the MODE selector, things are going to be easy: you'll get lush filters and very usable sounds, rhythmic tremolos, and oh, the Comet Trails! It will trigger the Omar Rodriguez Lopez within you! Past noon you'll step in a world of synth strings and hilariously bad tracking synths that will keep you both scratching your head in "how am I supposed to use this sound?" and sincerely amused. The possibilities are endless once you plug in an expression pedal, and this way you'll also get a very nice sounding wah, thus freeing up some pedalboard real estate. To cut it short: Omar Rodriguez Lopez uses one. JOHN FRUSCIANTE uses one. Are you better than these two? (No, you're not) Then it can work for you.

edited over 4 years ago
A beautiful invitation to creativity
A crazy sounds machine, but has the same trouble of his brothers, the drop down volume, so you have to use a new button mod to make the pedal TBP and adding a new patch... But it is a marvelous pedal but you have to spend some hours to figure how you gonna wisely

Sits on the shelf but...
I know a ton of professional touring musicians who use this all the time. Usually with some modifications but I have yet to use this guy very often. As you can tell on my board I'm a bit of a pedal hoarder-or more honestly-a gear hoarder but I love the options. Lots of stuff sits dusty only to be that key ingredient for some lil' part. Music is fun.

Discovering new sounds!
I bought this pedal for one reason: Crazy sounds! And I really got what I wanted.

Great!
Nice piece of gear! Useful and funny. I bought this because i was really courious to hear it. Now i love it because you can switch from a simple band pass effect to mutron style envelope filters, to tremorama style effect to oby wha (one of my favs) or string synth effects . They sounds really natural and clear but itsn't really simple and immediate like fm4 or other machines... enjoy
Line 6 Fm4
Line 6 Fm4 sounds great but I don't use it a lot

Endless features
Wow... Take some time to set it up right. The possibilities are endless. Really love this pedal.
Super Fun
I bought this pedal because of the obi wah and the voice box effect and I didnt realize how much fun all of the other filter setting would be. Its not just a fun pedal to have but a very useful one! Usually I think of fun pedals as a waste of musical potential because I can't see how it would sound good in a setting of a song or jam. However, with the FM4 I see a lot of practicality in almost every single one of the filter settings, excluding one or two. Overall, amazing pedal.