There are many different types of effects pedals for guitars, and they can be used to add a touch of flavour to your tone or to transform it into something almost completely different. Combinations of pedals can be used to create a complex sound, although they need to be chosen with care so that it doesn’t just become a mess.
All of these pedals are very confusing for the guitar neophyte, and so this article summarises all of the standard kinds of pedals that you’re likely to see. They are grouped into families of pedals that work in similar ways. The descriptions are intentionally short to keep this article to a reasonable length.
Gain pedals mimic the distortion effects of tube amplifiers, where the sound signal degrades at high volumes by clipping, which is distortion of the top and bottom of the sound waves. There are three main types of overdrive pedal
Overdrive – mild clipping
Distortion – high clipping, more aggressive
Fuzz – vintage-sounding, with low clipping
The best known filter is a Wah pedal, which actually has a pedal rather than just a footswitch. It is an envelope filter which increases the volume of a certain frequency range as you move the pedal, creating a “wah” sound! Auto-wah pedals also exist which do this dynamically in response to the attack of the notes that you play.
A Talk Box creates a similar effect, but is controlled via a tube going to the players mouth. The sound is played through the tube and re-recorded with a microphone, and so the sound changes according to the shapes made by the mouth.
Equalisers (or EQ) allow you to change the strength of different frequencies – they split the frequencies into three or more separately adjustable bands (treble, mid and bass). This can usually also be done on the amp but an EQ pedal allows adjustments without going to the amp. EQ rack units can give you much finer control over the frequencies, with many more sliders controlling smaller frequency bands (31 band EQs seem to be the most granular that are commonly available).
Volume pedals simply change the volume. Like wah pedals, they have a variable pedal rather than a footswitch.
Boosters change the volume by a set amount, increasing volume cleanly although this can then make the sound distort more at the amp. Some boosters act on specific frequencies, such as a treble booster.
Compressor/sustain pedals even out (or normalise) the dynamic range (loudness) of the signal. A compressor will reduce the louder signals and a sustain will increase the volume of softer signals – the same pedal often does both.
Noise gates control the sound output by suppressing sound below a certain threshold, aimed at eliminating noise from the pickups when you are not playing.
There are several types of pedal that copy or replace the original guitar signal at a different pitch. The most common types are:
Octave – copies the sound an octave up or down
Pitch Shift – shifts the sound to a different pitch
Harmoniser – adds harmony parts at specific intervals in the chosen key.
All of these effects work by replicating and adjusting the signal a short time after the original.
A Phaser works at a delay of around 1-15ms
A Flanger works at a delay of around 15-30ms
A Chorus pedal works around 20-50ms, and will add other effects such as oscillating the pitch of the delayed signal to create a shimmering effect.
Vibrato pedals add vibrato to the sound, replicating the vibrato (fluctuating the pitch) that the player can make by bending the strings or using a whammy bar (incorrectly called a ‘Tremolo’ by Leo Fender!).
Tremolo pedals rapidly fluctuate the volume to sound like the string is being repeatedly picked.
Ring Modulators multiply the sound with another fixed signal called the carrier wave, creating wild, synthetic sounds. The original Dalek voices were created using a ring modulator!
Time Delay Effects
Reverb pedals add echoes to the signal, emulating different room sizes and filling out the sound. Many amps have reverb built in.
Delay pedals repeat the signal at selected intervals, sometimes multiple times and often decreasing in volume. They can be used to fill out the sound, or to repeat the sound at longer intervals and create a multi-layered sound.
Looper pedals will repeat a phrase ad infinitum, allowing you to play a basic phrase of several bars and then play another track over it.
This one’s simple – tuning pedals tell you when your guitar strings are in tune! They usually also cut the sound to the amp while you are tuning.
ABY / switchers
These pedals simply switch your signal from one output to another, e.g. if you want to swap between two different amp setups.
Pedals that combine the functions of several types of effects pedals, often with multiple controls or switches and with programmable presets.
There are some other, more esoteric types of pedals, and I haven’t covered power supplies or advanced switching systems. I also haven’t attempted to address how you should order your pedals, but there are plenty of articles and videos on that topic on the Internet.