Line 6 FM4

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$195.62 Price Tier: Standard

4.5 (2)

1 Critic Review

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Page last updated Jun 10, 2026

Pricing and availability

We compare 600+ stores and found this item at 1 store. Prices updated June 10, 2026.

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5.0 (16)

$195.62 13 available Used

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Average Price: $196

Standard/Professional

$70

$251+

Price Tier

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

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Description

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Unlock a world of sonic exploration with the Line 6 FM4 – a powerhouse of filter effects that brings a treasure trove of sounds to your pedalboard. Designed for adventurous guitarists, this filter modeler offers over 13 unique modes, each inspired by iconic synth and auto-wah sounds from the golden age of music innovation. Whether you're looking to channel the experimental spirit of Frank Zappa, the smooth tones of Ernie Isley, or the unique stylings of Robert Fripp, the FM4 provides the tools you need to craft your signature sound.

From sweeping envelope filters to rich synth emulations, the FM4 is versatile enough to cater to your creative whims. Its user-friendly interface allows you to dive into complex soundscapes with ease, while maintaining the integrity of your original tone. It's more than just a pedal; it's a gateway to new musical frontiers. Perfect for live performances or studio sessions, the FM4 is an essential addition to any musician's arsenal, offering endless possibilities for those who dare to experiment.

Key Features:

Over 13 filter and synth modes
Inspired by legendary guitarists and their iconic sounds
User-friendly interface for easy sound customization
Ideal for live performances and studio work

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 offers 16 models of vintage and monophonic synth effects, providing a wide range of unique filter and wah sounds for creative expression.
How many presets are available on the Line 6 FM4?: The FM4 comes with 20 factory presets and allows for 4 user-programmable channels, giving you flexibility to store and recall your favorite settings.
Does the Line 6 FM4 support stereo output?: Yes, the FM4 features stereo input and output, allowing you to integrate it seamlessly into stereo rigs for expansive soundscapes.
Can I use an expression pedal with the Line 6 FM4?: The FM4 includes an expression pedal output, compatible with the optional Line 6 EX-1 expression pedal, enabling real-time control over parameters like frequency and mix.
Is the Line 6 FM4 suitable for live performances?: With its robust floor unit design, user-programmable channels, and expression pedal compatibility, the FM4 is well-suited for dynamic live performances.

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

Line 6 fm4 Bass demo

Poopathelegend

[cubisteffects] modded Line 6 Filter Modeler FM4 Expression Mod

cubisteffects

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

Capable of producing a vast range of unique and experimental sounds
Built like a tank, ensuring durability with proper care
Includes 16 well-modeled filter effects in one chassis
Save preset function for quick access to favorite sounds
Great for creating weird, glitchy synth effects
Compatible with an expression pedal for added versatility
Encourages creativity and experimentation in sound design
Easy to mod, repair, and upgrade according to user needs
Offers four accessible presets for on-the-fly changes
Ideal for players looking to expand beyond traditional guitar sounds

CONS

Toggle buttons are low quality and prone to failure over time
Not recommended for basic filter or natural wah sounds
Rubber under knobs can bind, making them difficult to turn
Requires additional gear like a booster or EQ for optimal tracking and sound quality

Owner Insights

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

Features and functionality

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The FM4 offers ease of preset access, which is a key advantage for users who prefer large pedals with multiple sound options.
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The Line 6 M5 contains all FM4 algorithms, supports MIDI, and is more compact, allowing for easier integration into smaller pedalboards.
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Comparisons

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The FM4's appeal includes its ability to replicate Fripp/Zappa/Rodriguez-Lopez sounds, making it particularly attractive for fans of experimental and progressive rock.
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The Line 6 HX series includes all FM4 effects, offers updates, better control, and patch saving, providing a modern alternative with enhanced features.
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User experience

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Some users prefer the FM4's model variety over the M5, despite the compact size of the latter, due to the FM4’s extensive soundscape options.
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FM4’s original power supply specification is 9VAC 1200mA, but it operates effectively with 12V DC when using compatible adapters and cables.
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Some users experience decision paralysis due to the vast array of sound options available, indicating a potential overwhelming factor for new users.
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Build quality

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The FM4, like the DL4, can suffer from button durability issues if not treated carefully, a common concern among long-term users.
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The M5 is noted for slightly more robust construction, particularly with easier switch replacement, addressing common durability concerns found in the FM4.
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Setup and maintenance

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Line 6 FM4 requires a 12V 1000mA center-positive adapter; incorrect polarity or pin size can cause malfunction or damage.
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The FM4 uses a 2.5mm power pin, differing from the typical 2.1mm, minimizing incorrect power supply usage.
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Software and compatibility

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Voodoo Lab Pedal Power 2 Plus can power the FM4 by setting a port to 12V DC with a specific red/black cable for center-positive connection.
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One Spot offers a conversion plug suitable for the FM4's unique power requirements, enhancing compatibility with various power supplies.
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Critic Reviews

Pedal Review: Line 6 FM4 | Delicious Audio

delicious-audio.com

The Line 6 FM4 Filter Modeler is a treasure trove for those craving a diverse range of quirky, synth-inspired sounds. While its interface can be cumbersome, with knobs that vary unpredictably based on presets, it redeems itself by allowing users to store settings—a nod towards user-friendly navigation. It shines in the realm of modern psychedelia and ambient music, offering a rich palette of effects from vocoders to synth modules. Although not as universally appealing as Line 6's DL4, and despite competition like the Electro Harmonix’s HOG with better note tracking, the FM4 stands out with its unique sound offerings at a reasonable price.

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4.5 out of 5

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