Modulation was one of the first guitar effects to hit the market. In short, modulation effects “modify” the pitch or volume of a guitar signal in different ways. There are several different types of modulation used today, but the main ones are tremolo, vibrato, chorus, phaser, and flanger.
In this article, I will break down the different types of modulation effects, give some examples of my favorite products, and advise you on how to use these effects. Let’s dive in, shall we?
What is a modulation effect?
Modulation effects are a subset of guitar effects that vary and add movement to your guitar’s signal by adjusting its pitch, amplitude, phase, or frequency. The speed or rate at which these movements occur is controlled by a “Rate/Speed” knob, and the intensity of the effect is generally controlled by a “Depth” knob.
The constantly moving or evolving sound characteristics you hear with modulation pedals are generally caused by linking one of the pedal’s parameters to a Low-Frequency Oscillator.
Modulation pedals are found in most genres of music, but a lot has changed since the original tremolo effects. There are several types of modulation effects that sound entirely different from each other. So, let’s break down the different types of modulation effects.
Tremolo
A tremolo pedal generally uses an LFO (Low-Frequency Oscillator) to modulate the volume of your guitar sound rhythmically. The first ever guitar pedal in 1946 was a tremolo effect called the DeArmond Tremolo Control.
Some guitarists like Yngwie Malmsteen, Dickey Betts, and Jeff Beck, to name a few, do volume swells by moving the volume knob in sync with the pulse of the song. This is the tremolo effect in action, just done manually.
By using a dedicated tremolo pedal or the one found on your amplifier, you can set the rhythm of your volume fluctuation, controlled by the “Rate/Speed” knob. You can also control the amount of volume used for the fluctuation with the “Depth” knob.
While rate and depth are found at the heart of any tremolo pedal, some of the advanced stompboxes have other features that allow you to tamper with the sound waves of the effect more precisely.
Lev’s pick: tremolo pedal
Boss TR-2
The Boss TR-2 is an industry standard for tremolo effects. It has a crisp earthquake-like effect with simple yet effective settings. You can adjust the rate, depth, and wave type of your tremolo.
Vibrato
In the simplest terms, a vibrato pedal functions similarly to a whammy bar with more customization options. While tremolo modulates volume, vibrato modulates pitch. Whammy bars are commonly called tremolo arms, which are fundamentally incorrect, as whammy bars are a vibrato effect. So, they are more accurately called vibrato bars.
Just like the tremolo’s controls, vibrato pedals have the same LFO-based designs, which modulate the pitch with a “Rate” and “Depth” knob.
When used in moderation, vibrato pedals can really breathe life into your guitar tone by adding the right amount of shimmer.
Lev’s pick: vibrato pedal
EarthQuaker The Depths
If you are looking for a great-sounding vibrato pedal with tons of customization, the Earthquaker The Depths is an excellent option. This pedal has a “voice” setting that allows you to adjust the tone of the vibrations. This pedal sounds similar to the psychedelic sounds of the 60s, and I compare it to a new and improved Univibe with more options.
Chorus
Just like in a vocal choir, chorus pedals allow you to replicate the sensation of multiple guitar voices playing simultaneously. While it sounds like a replica of the original guitar voice, chorus pedals actually work by slightly delaying the timing and altering the pitch of your original signal.
When these alterations are added to the original signal, you get a lush guitar tone with added sensitivity and a story to tell.
The chorus effect is synonymous with 80s music. I’m sure you’ve probably come across this effect as it was heavily used in the ‘80s by bands like Guns ‘N Roses, INXS, Whitesnake, the Police, and Duran Duran.
Lev’s pick: chorus pedal
MXR Analog Chorus
The Analog Chorus has a clear warm sound and plenty of settings to allow you to adjust the depth and rate of the modulation. It is a simple pedal that sounds great and works with most genres and playing styles.
Phaser
A phaser pedal creates a copy of your original signal and runs it through an all-pass filter. This filter alters the peaks and troughs of the copied signal and re-matches it with your original signal, making it go in and out of phase.
Similar to the tremolo pedal, an LFO in a phaser is used to control the “Rate/Speed” at which these in and out-of-phase movements occur.
Known to create complex swirling tones and, at times, outer space-like soundscapes, some stompboxes have multiple all-pass filters called “Stages” and also allow “Feedback” to add richness to your sound.
You can use phasers sparingly to highlight the key tones in a melody or use them in conjunction with a volume pedal while playing chords to create synth-like textures.
Many lead guitarists, including Jimi Hendrix, Jimmy Page, Eddie Van Halen, and Jonny Greenwood, use phasers along with their overdriven or distorted tones while soloing.
Lev’s pick: phaser pedal
MXR Phase 90
The MXR Phase 90 doesn’t have a lot of fancy bells and whistles, but it is an awesome and affordable all-around phaser pedal that can easily be used by beginners and gigging guitarists alike.
Flanger
Flangers and phasers are very similar effects with some key differences. A flanger also uses phasing but plays back a duplicate voice slower than the original. So while the two signals start at the same point, they diverge slowly over time as they run at different speeds.
While “Depth” and “Rate/Speed” are the staple of all modulation effects I’ve discussed here, flangers add controls like “Resolution,” “Manual,” “Width,” and “Flanger Modes.”
While used and abused to the extremes by Eddie Van Halen with his signature custom flanger EVH 117, the effect was surprisingly used way before by John Lennon on vocals to avoid having to double-track all the time.
You can hear the flanger in Lennon’s vocals on ‘Tomorrow Never Knows’ and the pedal in action on the Van Halen song ‘Unchained.’
Lev’s pick: flanger pedal
Boss BF-3
If you want to be able to adjust and customize your flanger pedal as much as possible, the BF-3 is a great option. There are 3 different flanger modes, and you can adjust the resolution, depth, and rate of your sound.
Where should you put modulation effects on your pedalboard?
The order of modulation effects in a guitar pedalboard depends on the genre, personal preference, setup, and how you’re placed within your band’s overall frequency spectrum. Typically, guitarists place modulation effects close to the end of their pedalboard, with the only pedals placed after being reverb or delay. Check my article explaining pedal order for more on this.
While it’s totally open for experimentation, I’ve listed some of the ways in which you could arrange them:
- Before Overdrive/Distortion
If you place modulation effects before your overdrive or distortion pedals, the modulation will impact a cleaner signal and then will be distorted afterward. This allows you to work intricately with the rate and intensity settings. - Before Reverb & Delay
If you place them before your reverb and delay pedals, the modulation effect can be heard clearly without being hidden by time-based effects, allowing for greater control. - After EQs & Filters
If you’re looking for phased-out or nasal tones, you can place them after filters and EQs. This allows you to sculpt and alter the EQed/filtered signal specifically to your taste without dealing with the full spectrum of sound. - Experiment!
Sometimes you find certain effects working better in front of the pedal chain, while others are better placed in the latter parts. If you’re looking to experiment with your pedals, it’s better to use one of the three steps mentioned above as a starting point. You can mix and match as you see fit and let your ear lead you from there.
Wrapping up
Don’t be scared to mix and match modulation effects to produce completely unique and wild sounds. The effects now seen regularly on pedalboards were once discovered by some brave guitarist who tried something new.
There are no guidelines. If it sounds nice, it probably is!
Want to learn more about how effects pedals work and how to use them? Check out my ultimate guide to effects!
