As a guitarist with a rather unhealthy love of pedals, I often add different types of modulation pedals to my pedalboard. Sometimes it works, sometimes it doesn’t.
But modulation isn’t always so easy to use or understand. Some types of modulation sound very similar, and some are named incorrectly. It’s a minefield.
But putting that all aside. Modulation can transform your tone into something beautiful, magical, and extraordinary. Whether you’re looking to add some subtle shimmer or go full-on psychedelic, modulation effects can get you there, from the swirling depths of a chorus pedal to the pulsating throb of tremolo.
So, I will tell you everything I know and have learned about modulation pedals—what they are, what types of modulations there are, and how to use them. We’ll even look at some recommended modulation pedals if you want to get started.
Key Takeaways
- Modulation pedals alter the frequency or amplitude of your guitar signal, adding movement, depth, and character to your tone.
- Modulation effects include tremolo, chorus, flanger, vibrato, UniVibe, rotary speaker, phaser, and ring modulation, each uniquely enhancing your sound.
- Iconic guitarists like Jimi Hendrix, Andy Summers, and Eddie Van Halen have used modulation effects to create their signature sounds.
- Hands-on experimentation with different pedals, settings, and signal chain placements is essential to finding your ideal tone.
- Typically, modulation pedals are placed after gain effects but before delay and reverb. You should experiment with placements, as you might stumble across something great.
Table of Contents
What Are Modulation Effects?
Modulation pedals alter the frequency or amplitude of your guitar signal over time, creating dynamic and expressive sounds. These effects can add movement, depth, and character to your tone, ranging from subtle shimmers to intense, psychedelic swirls. By continuously varying certain aspects of your sound, modulation effects can enhance the overall texture and complexity of your sound.
There are several types of modulation pedals (more on that later), and the specific sounds they produce can vary greatly. But they all operate on the same basic principle: splitting the guitar signal into two parts, delaying one part, and gradually changing it before blending it back with the original signal. This process involves elements of filtering and natural frequency changes, adding complexity and richness to
History and Classic Uses
Modulating a guitar tone has been a technique used since the early days of studio recording. Engineers would set up two tape recorders and slow one down to create flanging. This method they created laid the groundwork for all the more sophisticated modulation effects.
The phaser pedal appeared in the early 1970s, with companies like Oberheim, Maestro, and MXR leading the way. And by the mid-to-late 1970s, Electro-Harmonix and Roland (Boss) introduced the first flanger and chorus pedals. Guitarists had never had so much choice.
One of the key guitar players who popularized modulation was Jimi Hendrix. His use of a Uni-Vibe and phaser pedal added that swirling, psychedelic dimension we all love in Jimi’s sound, especially in his song “Machine Gun.”
Later, the Electro-Harmonix Electric Mistress flanger became a favorite of Andy Summers from The Police and played a big part in the song “Walking on the Moon.”
In the next decade, the 1980s, modulation effects continued to evolve and gained popularity. We saw chorus pedals become integral to the shimmering, clean tones of artists like The Cure’s Robert Smith and Metallica’s James Hetfield, who used the chorus to add depth to their guitar lines.
It’s also important to know that flangers and phasers were key tools for bands like Van Halen. Eddie Van Halen used the MXR Phase 90 to achieve his signature sound on tracks like “Eruption.”
Types of Modulation Pedals
Tremolo
The tremolo pedal is a classic modulation effect that rhythmically changes the volume of your signal. Quickly turning your volume up and down creates a pulsing effect that can range from a subtle shimmer to a choppy stutter.
Tremolo uses a low-frequency oscillator (LFO) to create a waveform that modulates the signal’s volume.
Classic tremolo effects typically use sine or triangle waves. Sine waves produce a smooth, lush tremolo, while triangle waves create a more pronounced, linear rise and fall, making peaks and valleys that can cut through a mix.
Modern tremolo pedals often include additional waveform options beyond the classic sine and triangle waves. For instance, a square wave can alternate the signal on and off, creating a bold, stutter-like effect when the depth is set to maximum.
Most tremolo pedals have at least two controls: rate and depth. The rate (or speed) knob adjusts the speed of the volume modulation. This helps you to sync the tremolo to the tempo of your song. The depth control sets the intensity of the effect, from subtle variations in volume to completely cutting the signal.
Listen to the audio example below to hear the classic pulsing effect of a tremolo pedal:
The DeArmond Tremolo Control, released in 1946, was the first standalone tremolo unit created. This paved the way for countless other tremolos, such as the BOSS TR-2. It sounds great and is really simple to use. More recently, it has become super popular. I see it on pedalboards everywhere: Harmonious Monk v2 by Jam Pedals.
Chorus
A chorus pedal often comes to mind when people talk about modulation pedals. This effect is the sound of the eighties. It creates a sense of multiple instruments or voices playing together slightly out of sync, replicating the natural variations you hear when a group of singers perform the same line. By mixing your clean signal with a modulating signal, the chorus effect subtly shifts the pitch of your note, creating a rich, expansive sound.
A chorus pedal works by splitting the guitar signal, duplicating it, and then slightly detuning the copy before blending it back with the original. This detuning is usually controlled by two controls: rate and depth. The rate control sets the speed of the pitch modulation, while the depth control determines the amount of detuning applied to the modulated signal relative to the clean signal. This combination allows you to adjust the effect to achieve anything from a gentle, shimmering texture to a more pronounced swirl.
Listen to the audio example below to hear the lush, big sound of a chorus pedal:
One of the most famous chorus pedals of all time is the BOSS CE-2, a true classic that has influenced countless others. Sadly, the CE-2 is now discontinued, but you can get some of the magic in the Boss Waza Craft reissue of the 1981 CE-2.
Flanger
The flanger effect, a favorite of the seventies, is created when the same signal is duplicated, and one of the signals is delayed slightly, usually by about 20 milliseconds. This tiny delay creates a delay line feedback loop when the two signals are mixed together, resulting in layers of sound that move and interact with each other. Adjusting parameters such as rate, range, or color can intensify this modulation, making the flanger a versatile and dynamic effect.
A flanger pedal works by duplicating the guitar signal and delaying it a tiny bit while shifting the delay time using a low-frequency oscillator (LFO). This creates a swirling harmonic effect ranging from a natural, tape-like warble to a dramatic, sci-fi raygun sound. The unique, jet-like motion of flanging can enhance solos, thicken riffs, or produce otherworldly noises.
Listen to the audio example below to hear the sweeping, jet-like sound of a flanger pedal:
The history of flanger dates back to the studio experiments of the late 1940s and 1950s. Legendary guitarist Les Paul is credited with the first recorded use of flanging in 1949, but The Beatles made the effect popular a decade later.
Originally, the only way to create flanging was to get identical source material on two tape machines simultaneously and physically apply pressure to the tape guide of one machine. This manual manipulation produced the sweeping cascade of sound that modern analog and digital stompboxes replicate today.
Flanger became a staple of 1960s and 1970s music, with iconic examples like Jimi Hendrix’s psychedelic flanging on “Axis: Bold as Love” and David Bowie’s wild flanging on the piano intro to “Ashes to Ashes.” The introduction of flanger pedals in the 1970s, such as the Electro-Harmonix Electric Mistress, made this effect widely accessible.
Eddie Van Halen famously used flanger in his signature sound, and it remains a favorite among guitarists for its ability to add depth and motion to their playing.
Some notable flanger pedals include the Lovetone Flanger With No Name, often called the “?”, the MXR Flanger, and the Meris Polymoon. My favorite, which has replaced some real classics on my board, is the ThorpyFX Camoflange—man, I love that pedal.
Vibrato
Don’t get this one confused with the tremolo arm on your guitar.
Vibrato is similar to the chorus but without the clean signal. While the chorus combines your clean signal with a modulated one to create a lush sound, vibrato is just the pitch modulation. You can usually control this pitch modulation by adjusting the pedal’s speed (rate) and intensity (depth) controls. The result is a dynamic up-and-down movement in pitch.
Listen to the audio example below to hear the dynamic pitch modulation of a vibrato pedal:
Vibrato has often been confused with tremolo because it was misnamed in the early days of electric guitars, amplifiers, and effects. Tremolo changes volume, whereas vibrato changes pitch. Despite this confusion, vibrato has a rich history and has recently become much more popular.
A famous example of a vibrato pedal is the discontinued BOSS VB-2, which has become highly sought after. But you can still get close to the magic with the BOSS WAZA VB-2W. Another excellent option is the TC Electronic Shaker, which is known for its simplicity, affordability, and effectiveness. The higher-end Diamond Vibrato is an analog chorus and vibrato pedal, which is my personal favorite vibrato pedal.
Much like chorus, Vibrato works by rhythmically shifting your signal’s pitch. It uses a low-frequency oscillator (LFO) to create a waveform that modulates the pitch. This process can add a subtle, vintage warmth to your tone or, when intensified, produce a pronounced, warbling effect.
UniVibe
The UniVibe is a slightly different modulation effect that has become a big name in the guitar world. Introduced in 1968, it was designed by Japanese engineer Fumio Mieda for a company called Honey, which later became Shin-Ei.
Mieda’s inspiration for the UniVibe’s sound came from his childhood experience of hearing radio waves bouncing off the atmosphere, causing a strange “washing” sound. This effect was not meant to replicate a rotary speaker, as many initially thought, but to create something unique.
The UniVibe’s distinctive sound is the result of a 4-stage filter that creates two moving notches. These notches, driven by a low-frequency oscillator (LFO), produce a sweeping, out-of-phase sound that gives the UniVibe its signature character. Depending on how it’s set, the effect can range from a subtle, warbling texture to a deep, pulsating throb.
I’m sorry, but I couldn’t get my UniVibe pedal back to record a sample for you. Blame Rob. He knows who he is. 😉
One of the key aspects of using a UniVibe is its placement in the signal chain. Many guitarists, including legends like Jimi Hendrix, have found that placing the UniVibe before the gain stages of an amplifier or dirt pedal yields the most pleasing results. When placed before your gain pedals, the UniVibe’s filters excite the harmonics of the distorted signal, creating a rich and full sound. Placing it after your gain pedals can result in a thinner, more filtered tone, as the effect removes harmonics that the distortion has already added.
This obvious advantage of pre-gain placement is because of how the UniVibe interacts with your signal. When the UniVibe modulates the signal before it hits the gain stage, the distortion process compresses and enhances the modulated frequencies, producing a more cohesive and controlled sound. On the other hand, placing the UniVibe after the gain stage allows the modulated frequencies to dominate, leading to a less balanced and more chaotic tone.
Despite being complicated to use, the UniVibe is loved by many guitar players worldwide for its ability to add depth and movement to a guitar tone.
Rotary Speaker
The rotating speaker effect is a classic modulation that creates a swirling, Doppler-like modulation of your guitar signal. Donald Leslie originally designed this effect to make the Hammond organ sound more like a pipe organ. Leslie created a rich, moving sound by putting a speaker inside a rotating baffle.
The Leslie speaker is made up of a large wooden cabinet containing two speakers: a rotating treble horn and a stationary woofer with a rotating baffle. This creates a 360-degree sound dispersion, resulting in a Doppler modulation effect. The Doppler effect changes the pitch of the sound due to its motion relative to the listener [1]. This is like when a car passes by you on the highway, and its engine appears to change in pitch as it approaches, and it lowers in pitch as it moves away.
Listen to the audio example below to hear the swirling, Doppler-like effect of a rotary speaker:
Okay, I cheated and used a plugin. Sadly, I don’t own a rotary speaker… Yet.
Original Leslie speakers have built-in tube amplifiers, which add a warm, organic overdrive to the sound. Modern digital and analog pedals, like the Strymon Lex, try to replicate this overdrive. This can be useful as it gives us guitarists a convenient and portable way to get the Leslie sound.
As with most effects, the placement of a rotating speaker effect in your signal chain can dramatically impact your sound. Many guitarists prefer to place it after gain stages. This can help to preserve the harmonic content of their distortion or overdrive. However, I recommend you experiment with different placements to see what you like best.
Phaser
The phaser is a classic modulation effect that became well-known in the 1970s. Phaser adds a swirling character to your guitar tone, making it a favorite among guitarists for decades. One of the most renowned phasers is the MXR Phase 90, introduced in 1974 by a company from Rochester, New York. This pedal quickly became a hit (and still is to this day) for its smooth and rich phasing effect.
The phaser works by splitting your guitar signal into two separate paths. One path remains unaffected, while the other passes through a series of all-pass filters that shift the phase of the signal. An LFO (low-frequency oscillator) modulates this phase-shifted signal, moving it back and forth in relation to the clean signal. As these signals move in and out of phase, they produce the characteristic phaser effect, creating peaks and troughs in the frequency spectrum, resulting in a dynamic, moving sound.
This interaction causes a muffling or dipping of tone when the signals are out of phase and a big spike in tone when they align. This is what gives the phaser its signature swoosh sound. Unlike the UniVibe, which has a harsher pulsing waveform, the phaser produces a true sine wave that is smooth and continuous.
Listen to the audio example below to hear the smooth, swirling effect of a phaser pedal:
Phasers usually have controls for adjusting the speed (rate) and intensity (depth) of the modulation (you’re probably seeing a pattern here). The rate control sets the speed at which the LFO modulates the phase-shifted signal, while the depth control determines the extent of the phase shift. These controls help you adjust the effect, from subtle, shimmering waves to deep, dramatic swooshes.
While there are many great phaser pedals out there, I really love the MXR Phase 95. It’s affordable and versatile. The Phase 95 includes multiple phase effects from MXR’s history, such as the Phase 45 and the Phase 90. This lets you explore a range of phasing sounds in one pedal.
Ring Modulation
Originating in the 1970s with pioneering pedals like the Electro-Harmonix Frequency Analyzer, ring modulation has carved out a bit of a niche for itself as the go-to effect for creating wild, otherworldly sounds.
Ring modulation combines your guitar signal with a carrier signal, typically a sine or square wave generated within the pedal. This interaction produces the sum and difference of the frequencies input, resulting in a harmonically rich and complex sound. The effect can range from metallic and bell-like tones to dissonant, robotic noises. It’s a different style of modulation than what you get from a chorus or a flanger, offering a sound that’s both unpredictable and captivating.
Listen to the audio example below to hear the unique and unpredictable sounds of a ring modulation pedal. This effect can take many forms:
The mechanics behind ring modulation are rooted in the principle of superimposing one waveform onto another. This technique generates new frequencies that are not present in the original signal, creating a unique tapestry of sound. The result is an effect that can add layers of madness, warbles, pitches, and ringing sounds to your guitar tone.
One of the early commercial ring modulators was the Moog Ring Modulator Model 101, developed by Dr. Robert Moog in the 1960s and 70s. Originally designed for synthesizers, the ring modulator quickly found a home among adventurous guitarists and sound designers. Another notable early ring modulator was created by Harald Bode, who incorporated it into his Melochord keyboard in the 1950s.
Modern ring modulators, like the Electro-Harmonix Ring Thing, continue to push the capabilities of what a ring modulator can do. The Ring Thing, for example, offers a wide array of sounds, from subtle pitch shifting to extreme, goblin-like tones (you gotta try it). If you love to experiment and explore new wild territories, this is an effect for you.
Key Parameters of Modulation: Rate and Depth
If you made it through the previous sections, you’ve probably noticed a pattern for controls on most modulation pedals.
- Rate
This controls the speed or frequency of the modulation effect. Adjusting the rate allows you to go from a slow, sweeping motion to a fast, pulsing rhythm. - Depth
This controls the intensity or amplitude of the modulation. Increasing the depth can make the effect more pronounced and dramatic, creating bold and striking sounds. A lower depth setting keeps the effect more subtle and understated, adding a gentle touch to your tone.
How to Use Modulation Pedals: Top Tips
If you’re just getting started with modulation, here are some tips to help you get going.
1. Try Different Types
First things first, get to know your modulation pedals. Chorus, flanger, phaser, tremolo, Uni-Vibe, and rotary speaker effects each have their unique flavor. Start by trying them out one at a time. Play around with the settings and see how they affect your tone.
Okay, I know you can’t buy every type. But look for a multi-effects unit or something that allows you to experiment without breaking the bank. It really is the only way.
2. Take Your Time
Most modulation pedals have controls for rate and depth. Start with both at noon and adjust from there. Dial back the depth for a more subtle effect. Or crank it up for something more in-your-face.
Take your time with this step, and don’t be afraid to adjust later.
3. Layer and Combine
Try combining different modulation effects together. A touch of tremolo with a slow phaser can add amazing movement to ambient passages. Or stack a flanger after your chorus for a one-way ticket back to the 80s.
While doing this, ensure you experiment with the order of your pedals. Putting your chorus before overdrive can sound very different from putting it after. Don’t listen to anyone who tries to tell you the rules – especially not me (see next section). Find out and experiment yourself.
4. Where to Place Modulation in the Signal Chain
Modulation effects are typically placed between gain effects and delays, and this has worked well for me in most cases.
David Gilmour, for example, usually places his Uni-Vibes, phasers, flangers, and chorus pedals after his overdrives and fuzz pedals, with rotary cabinets last, along with the main amps.
Phasers and Uni-Vibes often sound better when placed before gain effects, while flangers and chorus tend to work well after. But refer to point 3. Don’t listen to anyone else. Just see what works for you.
The Best Modulation Pedals for Guitarists on a Budget
Let’s look at some wallet-friendly, best modulation guitar pedals that could be a great introduction to the world of modulation.
Try Budget-Friendly Brands at First
You don’t need to spend a lot to get a great modulation pedal. There are plenty of brands, such as Caline, Behringer, Biyang, and Danelectro, who create fantastic, affordable effects pedals. If you’re just looking for a great value introduction to modulation, I recommend you go with one of these brands.
Multi-Modulation Pedals Give You More for Your Money
A multi-modulation pedal might be what you’re looking for to try all of these modulations without spending a fortune on individual pedals. They offer a variety of effects in a single pedal, making them ideal for experimenting with different sounds.
I’d recommend the FLAMMA FC-05. It’s tremendous value and gives you eleven different flavors of modulation effects. When writing this article, it’s around the $40 mark.
If you’re willing to spend a little more, you could also try the Joyo Vision (around $90) or even the, quite a bit more expensive, Boss MD-200 ($300). But there are loads out there. Do some Googling, watch some YouTube videos, get yourself to your local store, and find one you like.
The great thing about multi-modulation pedals is that you can experiment with various modulation flavors and find a sound you like without breaking the bank.
Single-Effect Modulations
Sometimes, you just want one effect done well. I get it. That’s where single-effect modulation pedals come in. These pedals focus on delivering great modulation without the bells and whistles. They’re perfect if you know exactly what you want and don’t need a Swiss Army knife of effects.
The Boss CE-2w is a popular choice for analog chorus tones. The MXR Micro Flanger is a great option for flanger enthusiasts, and the EVH Phase 90 is an excellent choice for phaser effects. The Boss TR-2 Tremolo is also a favorite for its versatile tremolo effect.
FAQs
What is the most versatile modulation pedal?
The Strymon Mobius is considered one of the most versatile modulation pedals. It offers a wide range of effects, including chorus, flanger, phaser, tremolo, vibrato, and many more, all in one unit. With extensive controls and high-quality sound, it’s a go-to choice for guitarists looking for maximum flexibility and creativity in their modulation effects.
What are modulation effects?
Modulation effects are audio effects that change the sound of your guitar by altering its frequency, timing, or volume. These effects include chorus, flanger, phaser, tremolo, and vibrato, each adding unique movement and depth to your tone.
Where do you put the modulation pedal in a chain?
Modulation pedals are usually placed in your signal chain after gain effects (like overdrive and distortion) but before time-based effects (like delay and reverb). This placement helps preserve the harmonic content of your distortion while allowing the modulation effects to enhance your tone without becoming muddy. However, try different placements, and trust your ears to find what works best for you.
To Sum Up
Ultimately, it’s important to understand what modulation does for your tone. Sure, you can read articles and watch YouTube videos, but nothing will help you feel the difference between the modulation types better than playing them yourself.
So whether you’re looking to add some subtle depth to your clean tones or go full-on psychedelic with wild, warbling effects, modulation can help you get there. My advice is to find a modulation pedal you like and get to know it. Don’t rush. Remember that you don’t need to use all modulations straight away.
Take it one step at a time, and enjoy the process of discovering how modulation can help your sound.
