Photo of Line 6 FM4 Filter Modeler and more gear in a pedalboard and pedal

Photo of Line 6 FM4 Filter Modeler and more gear in a pedalboard, studio, and guitar

Line 6 FM4 Filter Modeler

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Equipboard's ranking is determined by analyzing factors such as professional artist usage, popularity, user ratings, reviews, and more.

$225.00 Price Tier: Standard

4.5 (54)

1 Critic Review

10 Reviews

This product is Vintage or Discontinued

Find out who is using Line 6 FM4

5 community setups

59 wishlisted

151 saved

Page last updated Jul 04, 2026

Pricing and availability

We compare 600+ stores and found this item at 2 stores. Prices updated July 4, 2026.

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Reviews

Price

5.0 (16)

$225.00 13 available Used

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5.0 (1)

$249.99

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Average Price: $122

Standard/Professional

$70

$251+

Price Tier

In the Filter Effects Pedals category, Line 6 FM4 Filter Modeler is priced in the Standard/Professional range. This is quality gear at a fair price point, suitable for beginners, hobbyists, and pros alike.

Budget

Standard

High-end

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Description

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The Line 6 FM4 Filter Modeler is a creative powerhouse for adventurous musicians. Housing over 13 distinctive and explorative modes, it’s your go-to pedal for innovative sound shaping. Whether it's classic synth or auto-wah emulations you're after, the FM4 has got you covered. Perfect for those who dare to get weird, just like musical legends Frank Zappa, Ernie Isley, Peter Frampton, or Robert Fripp.

Key Features:

Offers over 13 different filter modes
Includes classic synth and auto-wah emulations
Ideal for experimental and innovative sound shaping
Inspired by the sounds of iconic musicians
A must-have for those seeking unique tonal possibilities.

Product specs

Brand	Line 6
Model	FM4 Filter Modeler
Finish	Purple
Year	2010s
Made In	United States
Categories	Filter and Wah Pedals
Pedal Format	Floor Unit

FAQs

What types of effects can the Line 6 FM4 Filter Modeler produce?: The Line 6 FM4 Filter Modeler offers a variety of filter effects, including classic synth effects, envelope filters, and auto-wah. It provides a wide range of modulation and filter options suitable for experimental and traditional sounds.
Is the Line 6 FM4 suitable for use with bass guitars?: Yes, the Line 6 FM4 Filter Modeler is compatible with both electric and bass guitars, providing rich and dynamic filter effects that enhance the tonal palette of bass instruments.
What power supply does the Line 6 FM4 Filter Modeler require?: The Line 6 FM4 Filter Modeler requires a 9V DC power supply, which is typically included with the pedal or can be purchased separately if needed.
How does the Line 6 FM4 compare to traditional wah pedals?: Unlike traditional wah pedals, the Line 6 FM4 offers a diverse range of filter effects beyond the standard wah, including synth-like and envelope filter sounds, making it more versatile for creative sound design.
Can the Line 6 FM4 Filter Modeler be used in a live performance setting?: Yes, the Line 6 FM4 is designed for live use, with durable construction and intuitive controls that make it easy to switch between effects on stage.

Videos

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gearwire

Line 6 FM4 Filter Modeler: Change Your Filter Models Often

gearwire

FM4 Filter Modeler Overview | Line 6

Line 6

Line 6 FM4 Filter Modeler | Reverb Demo Video

Reverb

Line 6 FM4 (Filter Modeler) Sounds demo

mauricio méndez

Why We Love the Line 6 FM4 Filter Modeler Pedal (And You Should Too)

Raccoon Point Studios

Line 6 FM4 Filter Modeler Overview

PromenadeMusicTV

Reviews

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PROS

Wide range of unique sounds, from lush filters to digital tones
Durable build, described as "built like a tank"
Save preset function for favorite sounds
Versatile, with applications from intros to full song parts
Can be easily modified, repaired, and upgraded
Encourages creativity and exploration of new sounds
Used by professional musicians, adding to its credibility
Compatible with expression pedals for expanded control
Some settings offer practical use in song/jam settings

CONS

Learning curve to get decent sounds
Requires specific power supply, not included
Footswitch design is less durable than standard footswitches
Heavy and bulky, taking up significant pedalboard space
Some effects have poor tracking or sound quality
Tends to drop down volume, may require modifications to fix
Not all filter settings are useful or practical in a mix

Owner Insights

We analyzed real musician discussions from forums and Reddit to find what players love, question, and tweak about Line 6 FM4 Filter Modeler.

Build quality

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Owners suggest treating FM4 pedals gently to avoid button wear, as rough usage has led to complaints about durability.
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Upcoming v2 release promises improved construction, addressing previous durability concerns.
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Features and functionality

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The FM4's preset access is praised for its convenience compared to the M5, appealing to users who prefer larger, more accessible pedals.
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The pedal is compatible with various isolated brick power supplies that accommodate the unique power requirements of the Line 6 4-series.
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The HX series includes all FM4 effects, offers more updates, and better control/patch saving options for a broader sound exploration.
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User experience

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The FM4 is favored for its ability to recreate unique sounds reminiscent of artists like Fripp, Zappa, and Rodriguez-Lopez, offering a distinctive tonal palette.
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Owners experience option overload with the HX series, leading to decision paralysis despite its versatility.
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Comparisons

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Despite reliability issues, the DL4's sampling and reverse capabilities are highlighted as superior for creative use compared to the Boss DD-20.
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The FM4's power requirements are noted as unusual, needing 9 volts AC instead of the more common DC, setting it apart from many other pedal types.
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The M5 includes all 4-series algorithms, MIDI capability, and offers a more compact size and easier switch replacement.
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Setup and maintenance

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Line 6 FM4 requires a 12v 1000mA center positive power supply with a 2.5mm center pin, differing from the standard 2.1mm center negative pedals.
Source
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Owners suggest using a Voodoo Lab Pedal Power 2 Plus with a dip switch set to 12V DC and a specific red/black center positive cable for optimal performance.
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It's necessary to ensure the power supply provides at least 500 mA; otherwise, the pedal may malfunction or behave unpredictably.
Source

Critic Reviews

Pedal Review: Line 6 FM4 | Delicious Audio

delicious-audio.com

The Line 6 FM4 Filter Modeler is a treasure trove for experimental musicians, packing a variety of vintage filter effects from Moog, Korg, and Oberheim into one digital stompbox. It's not as user-friendly as its sibling, the DL4, but its ability to recreate everything from vocoders to synth modules makes it a hit for modern psychedelia and synth-inspired genres. While its layout can be confusing, the FM4's sound versatility stands unmatched in its price range. A must-have for those seeking unique sonic adventures, despite its navigation quirks.

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Full Review

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4.5 out of 5

Based on 10 Reviews and 54 Ratings

5 star

4 star

3 star

2 star

1 star

matteo_cola

152

almost 7 years ago

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.

jp_belanger

619

over 5 years ago

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!

stravoxid

806

almost 5 years ago

This is so old that I like it :)

The quest began with the fact that I was looking for a power supply unit. You need to buy a power supply with a minus in the center! 1200mAh is optional. The pedal actually consumes about 350 - 500. I bought a 9V 1000 mAh, that's enough.

I heard this pedal for the first time on Buckethead's records. I postponed the acquisition for a long time, but in the end, the desire to have fun won out common sense. This pedal is over 20 years old! But it tears and flies. If you want to add variety to your sound, this is it. Personally, I plan to use it for intro at concerts using the Attack Synth effect. Also, the rest of the effects fit very well into small fragments of songs. The pedal isn't perfect for 2021. It is heavy, large and poorly read low frequencies, which is why sound is often lost. But damn, it warms my soul. And great musicians still keep it in pedalboards.

Roles:

Guitarist Audio Engineer

Genres:

Rock Indie rock Progressive rock

joethekidmc

over 7 years ago

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.

valeriomina

about 10 years ago

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

xaqary

5455

about 9 years ago

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.

rodrigotaylormusic

119

over 10 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