Types of Guitar Effect Pedals
Distortion and Over Drive
The most popular effects pedal of all time. The type of distortion varies widely depending on the pedal from smooth and fuzzy to coarse and rough. If you are playing heavy metal, punk rock or some type of hard rock a distortion or overdrive pedal is essential.
Most distortion pedals work by emitting a square sound wave at the same frequency as the input from the guitar. The two are then blended together. The proportion of square wave to normal sound is then adjusted by a distortion dial. The more square the wave, the more distorted the guitar will sound. Many guitar amplifiers also come with built in distortion.
Common Controls on Distortion or Overdrive pedals:
- Level – adjusts the amount of volume.
- Presence – Produces bright high frequencies and fat low ones.
- Distortion or Overdrive – Adjusts the amount of distortion.
Phasing and Flanging
A phaser or flanger gives the guitar a rich sound that seems to blend up and down. A phaser works by splitting the sound signal from a guitar pick up into two. The two sound signals are then shifted to be out of phase with each other. This process is also known as phase shifting and is the basis of both flanging and phasing. The signals are put out of phase by altering the speed of one signal, which affects the pitch.
Common Controls on Phaser or Flanger Pedals:
- Manual – sets the delay time
- Depth – adjusts the sweep range; how far the sounds go ‘out of place’.
- Rate – Determines the sweep speed.
- Resonance – Controls the amount of feedback.
Noise gates cut out background noise and are essential for any type of serious recording. If you use several pedals it is useful to install a noise gate as the last pedal before the guitar amp.
Noise gates have a control called release time. This affects the speed with which the noise gate opens and closes. A fast release could create a more punchy sound by cutting the decay (the time it takes for a sound to fade), giving a brief clipped note.
Chorus effects are also accomplished through phase shifting, which can create delay and changes in pitch. Small changes in both can create the sound of one instrument sounding like many in unison. This gives a very full effect if strumming.
Common Controls on Chorus Pedals:
- Rate – varies the intensity.
- Depth – controls sweep width.
- Tone – boosts the treble.
Delay and Sampling
Delay foot pedals create delay digitally. This is a very versatile effect. It is possible to obtain resonant, echoey sounds as with reverb but you can also gain an audible echo. The volume and pit of this echo can be adjusted, as can delay time between echoes.
The echo is a digital recording, held temporary in the pedal’s memory. Many delay pedals take this one step further with a ‘hold’ facility which enables them to record or ’sample’ a riff or chord. It is then possible to play a different riff or chord over the sample as it repeats.
Common Controls on Delay and Sampling Pedals:
- Delay level – affects the volume of the delay.
- Feedback – adjusts the speed at which the signal is repeated.
- Delay Time – adjusts the speed at which the signal is repeated.
- Range – has four pre-set delay ranges which govern how pronounced the echo effect is.
- Hold – has three positions; off, unlatched and latched.
This device emphasizes a specific band of frequencies. The movements of the pedal control moves the band of frequencies up or down the audio spectrum, so the same note can sound ‘fat’ or ‘thin’.
This pedal was very popular in the late 1960’s, the most famous version called the ‘Cry Baby’, used extensively by Jimi Hendrix. With the ‘Wah Wah’ effect a wide variety of sounds can be achieved.
Compressors and Limiters
Compressors and limiters are used to reduce the dynamic range of a sound signal before it reaches a loudspeaker. An unsubtle form of manual compression would be to pull down a fader control during loud passages in a studio. The advantage of electronic devices is that they respond much quicker than the human ear to variations in volume.
Limiters are used in studios or in situations where excessive volume control could damage the human ear, loudspeakers or other equipment. They enable you to set a maximum volume threshold so that at high volumes the output remains constant. Compressors work along a similar principle. Instead of altering gain to preserve a fixed output level, the compressor changes the amplifier’s ratio. For example, before compression, the ratio is 1 to 1.
This means that if the input voltage rises by one volt. If a compressor changes the ratio to 2:1, the output voltage would only rise by half a volt for each one volt rise in output. In terms of playing, compressors help sustain without distortion and reduce differences in volume between strings, low and high notes, harmonics and real notes. It also gives a very ‘gutsy’ rhythm sound.
Common Controls on Compressor and Limiter Pedals:
- Sustain Control – determines the sustain time
- Tone Control – gives a variety of tone colors on the effect sound.
- Attack Control – determines the time the compressor takes to react to any
- excessive volume, so that even notes of a quick passage can be compressed.
- Level Control – adjusts the volume balance between the effect and normal signals.