Effects Pedals 101: Modulation

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Since the birth of the electric guitar in the 1930s, guitarists have been looking for ways to warp and enhance their signature sounds. The world of guitar effects is a mammoth one, and it can feel a bit overwhelming to know where to begin your journey to becoming a #guitargod. The most important thing to know is that a guitar effects pedal serves to take the initial “natural” signal of the instrument itself and change that signal into something different.

Whilst there is a lot of crossover and intersection, there are four general categories that pedals can be divided into:

  • Pedals that modulate a signal
  • Pedals that boost, compress or distort a signal
  • Echo and delay effects
  • Everything else: filter, modelling and multi-effects

In this article, we will focus on modulation pedals, and explore some of the types of sounds that can be created with a range of interesting pedals.

Modulation effects work by disturbing a signal’s pitch and/or frequency to create everything from otherworldly spaceship sounds to a classic vibrato. Some popular types of modulation pedals include: phasers, flange, vibrato and tremolo, and octave divider.


A phaser pedal splits a signal and plays back the two paths at different wavelengths to produce a spacey sound. You can hear the sound of the phaser on the Rhodes intro to Billy Joel’s ‘Just The Way You Are’.

Noisegate’s pick:

PH-3 Boss

This Boss pedal adds a little spice to the classic phase, allowing users to control not only the speed of the effect but also the depth of the dips and the resonance of the effect.

DOD-201 Phasor

Based on one of the first phaser pedals ever made (over 40 years ago), this is a classic analogue phaser effect.

DOD-201 Phasor
PH-3 Boss


Flanger is very similar to phaser in that it splits the signal into two. However whilst it does slow down one of these halves (like the phaser) it then speeds the signal back up again to meet the original. This alternating of speeds creates the classic sweeping effect of the flanger. There is flanger used boldly on the opening guitar riff to Heart’s ‘Barracuda’.

Noisegate’s pick:

Digitech Nautila Chorus Flanger

A stylish little stomp-box that combines the chorus sound and flanger effect into one pedal.

Electro-Harmonix Stereo Electric Mistress

Whilst most pedals made by Electro-Harmonix are analogue, this simple flanger pedal is actually digital. Don’t let this dissuade you though, even the purest of purists will have trouble distinguishing between this pedal and a class analogue flange.

Digitech Nautila Chorus Flanger

Vibrato and Tremolo

Often found sharing on effects pedal, vibrato and tremolo sound quite similar. They are actually two completely effects. Not actually a modulation effect but rather a dynamic effect, tremolo uses the variations in a note’s volume in order to produces a shuddering sound. Vibrato is a classic modulation effect, using small and fast shifts in a note’s pitch to make it sound as though it is vibrating. Guitarist’s often use a whammy bar to manually create vibrato on their instrument. A very famous example of the tremolo effect can be found on Tommy James and the Shondells’ track ‘Crimson and Clover’.

Noisegate’s pick:

TC Electronic Shaker Vibrato Pedal

Solid manufacturing and excellent quality control means that this TC Electronic pedal is guaranteed to operate in full flight directly from the factory. However it will respond well to user manipulations which can be controlled through the impressive TonePrint technology that is included in this pedal.

Digitech VENTURA VIBE Rotary/Vibrato

Inspired by vintage phaser-based Uni-Vibe effects, this pedal includes a pure pitch-based vibrato effect as well as a vintage-sounding rotary effect based on the Leslie speaker sound.

TC Electronic Shaker Vibrato Pedal

Behringer Ultra Vibrato UV300

The best we could find when it comes to ultra-budget vibrato pedals, this Behringer pedals aims for a 60s and 70s vibrato sound. It’s a very heavy hitting pedal with many choices of vibrato for such a basic pedal.

Octave Divider

Very simply, the octave divide plays your original signal back at a higher or lower octave. The most famous example of this is probably used by Jack White of the White Stripes, heard clearly in their song ‘Seven Nation Army’. For a band that didn’t have a bass player, the octave divider was useful in providing a wider range for the bottom end of the guitar.

Noisegate’s pick:

EarthQuaker Devices Tentacle Analog Octave Up Effects Pedal

An excellent boutique pedals range, EarthQuaker Devices have really, really gone back to basics with this octave pedal. It only offers one octave up. However keep in mind that this pedal is designed to be used as octave pedals were originally used, in combination with a good fuzz pedal. And since it’s analogue this pedal is very hi-fi in it’s sound quality and sensitive to your selection of pickups, tone setup and more.

WHAMMY-DT Digitech

Digitech DROP Compact Polyphonic Drop Tune Pitch Shifter

This pedal is dedicated solely to pitch shifting and allows a player to change their signal from only one semitone all the way down to a full octave.

WHAMMY-DT Digitech

The most complex pitch shifter of our picks, this pedal allows players to play with pitch in a number of ways and include an expression pedal for quirky squeals and monster dive bombs lower than any whammy bar would allow. Numerous settings all relating to pitch on this pedal, definitely for a deeper exploration!

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