# Guitar/Effects Pedals

**Effects pedals** are electronic or digital devices that modify the
tone, pitch, or sound of an electric guitar. Effects can be housed in
effects pedals, guitar amplifiers, guitar amplifier simulation software,
and rackmount preamplifiers or processors. Electronic effects and signal
processing form an important part of the electric guitar tone used in
many genres, such as rock, pop, blues, and metal. All these are inserted
into the signal path between an electric instrument and the amplifier.
They modify the signal coming from the instrument, adding \"effects\"
that change the way it sounds in order to add interest, create more
impact or create aural soundscapes.

Guitar effects are also used with other instruments in rock, pop, blues,
and metal, such as electronic keyboards and synthesizers. Electric bass
players use bass effects, which are designed to work with the
low-frequency tones of the bass.

## Distortion-related effects

!Boss DS1 distortion
pedal Distortion is an
important part of an electric guitar\'s sound in many genres,
particularly for rock, hard rock, and metal. A distortion pedal takes a
normal electric guitar signal and combine harmonic multiplication and
clipping through the use of analog circuitry to create any number of
sounds ranging from a mild vintage blues growl to a 1960s psychedelic
fuzz sound to the sound of an highly overdriven tube amp in a metal
band. Distortion is essential to the powerful sound of heavy
metal music.

There are several different types of distortion effects, each with
distinct sonic characteristics. These include overdrive/distortion (or
vacuum tube-style distortion), overdrive/crunch, fuzz, and hi-gain.

### Overdrive Distortion

Overdrive distortion is the most well known of all distortions. Although
there aren\'t many electronic differences between a distortion an
overdrive, the main audible one is that a distortion does exactly as the
name suggests; distorts and clips the signal no matter what volume is
going through it, the amount of distortion usually remains relatively
the same. This is where an overdrive differs. Most overdrives are built
to emulate the sound of a tube amp overdriving and therefore give the
player control of the clipping through dynamics. This simply means that
the effect gives a clean sound for quieter volumes and a more clipped or
distorted sound for louder volumes.

While the general purpose is to emulate classic \"warm-tube\" sounds,
distortion pedals such as the ones in this list can be distinguished
from overdrive pedals in that the intent is to provide players with
instant access to the sound of a high-gain Marshall amplifier such as
the JCM800 pushed past the point of tonal breakup and into the range of
tonal distortion known to electric guitarists as \"saturated gain.\"
Although most distortion devices use solid-state circuitry, some \"tube
distortion\" pedals are designed with preamplifier vacuum tubes. In some
cases, tube distortion pedals use power tubes or a preamp tube used as a
power tube driving a built-in \"dummy load.\" Distortion pedals designed
specifically for bass guitar are also available. Some distortion pedals
include:

-   MXR Distortion+: A distortion which is capable of having a very
    subtle, soft clipping, right through to a heavily overdriven sound
    favoured by many modern day heavy and death metal guitarists.
-   Pro Co Rat
-   Boss DS-1 Distortion
-   Marshall Guv\'nor
-   Line 6 Dr. Distorto
-   T-Rex Engineering\|T-Rex Engineering\'s Bloody Mary
-   Digitech Hot Head
-   Danelectro FAB Distortion

### Overdrive/Crunch

!Ibanez Tube Screamer
pedal

Some distortion effects provide an \"overdrive\" effect. Either by using
a vacuum tube, or by using simulated tube modeling techniques, the top
of the wave form is compressed, thus giving a smoother distorted signal
than regular distortion effects. When an overdrive effect is used at a
high setting, the sound\'s waveform can become clipped, which imparts a
gritty or \"dirty\" tone, which sounds like a tube amplifier \"driven\"
to its limit. Used in conjunction with an amplifier, especially a tube
amplifier, driven to the point of mild tonal breakup, short of what
would be generally considered distortion or overdrive, these pedals can
produce extremely thick distortion sounds much like those used by Carlos
Santana or Eddie Van Halen. Today there is a huge variety of overdrive
pedals, and some of them are:

-   Ibanez Tube Screamer (TS-9 and TS-808): an overdrive which was built
    to work with the harmonics of a push-pull tube amp. This effect was
    made famous by blues guitarist Stevie Ray Vaughan but was and is
    used by hundreds of prominent guitarists since it\'s invention.
-   BOSS SD-1 Super Overdrive
-   BOSS BD-2 Blues Driver
-   BOSS OD-3 Overdrive
-   Line 6 Crunchtone
-   DigiTech Bad Monkey
-   N-audio Firesound V3
-   Danelectro FAB Overdrive

### Fuzz

!Arbiter Fuzzface, a fuzz
pedal. Fuzz was
originally intended to recreate the classic 1960\'s tone of an
overdriven tube amp combined with torn speaker cones. Oldschool guitar
players (like Link Wray) (citation needed) would use a screwdriver to
poke several holes through the paperboard part of the guitar amp speaker
to achieve a similar sound. Since the original designs, more extreme
fuzz pedals have been designed and produced, incorporating octave-up
effects, oscillation, gating, and greater amounts of distortion.

Some classic fuzzbox pedals include:

-   Sola sound MK 2 tonebender
-   Univox supa-fuzz
-   Mosrite fuzzrite
-   Dallas Arbiter Fuzz Face: This was a favorite of Psychedelic rocker
    Jimi Hendrix who shot this pedal to stardom as he did himself.
-   Electro Harmonix Big Muff: Probably the most popular fuzz effects
    ever designed, the Big Muff is also often used as a sustain pedal
    and sounds excellent in combination with a wah wah.

### Hi-Gain

Hi-Gain (descended from the more generic electric guitar amplification
term high-gain) is the sound most used in heavy metal. High gain in
normal electric guitar playing simply references a thick sound produced
by heavily overdriven amplifier tubes, a distortion pedal, or some
combination of both\--the essential component is the typically loud,
thick, harmonically rich, and sustaining quality of the tone. However,
the Hi-Gain sound of modern pedals is somewhat distinct from, although
descended from, this sound. The distortion often produces sounds not
possible any other way. Many extreme distortions are either hi-gain or
the descendents of such. The Mesa Boogie Triple Rectifier Series of amps
are an example.

Some Hi-Gain Pedals Include:

-   BOSS MT2 Metal Zone
-   DigiTech Death Metal
-   Danelectro FAB Metal
-   Electro Harmonix Metal Muff with Top Boost
-   MXR Dime Distortion: Used by Dimebag Darrell.
-   Suhr Riot

### Power-tube pedal

A Power-Tube pedal contains a power tube and optional dummy load, or a
preamp tube used as a power tube. This allows the device to produce
power-tube distortion independently of volume; therefore, power-tube
distortion can be used as an effects module in an effects chain.

### Power attenuator

A Power attenuator enables a player to obtain power-tube distortion
independently of listening volume. A power attenuator is a dummy load
placed between the guitar amplifier\'s power tubes and the guitar
speaker, or a power-supply based circuit to reduce the plate voltage on
the power tubes. Examples of power attenuators are the Marshall
PowerBrake and THD HotPlate.

## Filtering-related effects

### Equalizer

!Behringer EQ700 graphic
equalizer

An equalizer adjusts the frequency response in a number of different
frequency bands. A graphic equalizer (or \"graphic EQ\") provides slider
controls for a number of frequency region. Each of these bands has a
fixed width (Q) and a fixed center-frequency, and as such, the slider
changes only the level of the frequency band. The tone controls on
guitars, guitar amps, and most pedals are similarly fixed-Q and
fixed-frequency, but unlike a graphic EQ, rotary controls are used
rather than sliders.

Most parametric EQ pedals (such as the
1 Boss PQ-4)
provide semi-parametric EQ. That is, in addition to level control, each
band provides either a center frequency or Q width control. Parametric
EQs have rotating controls rather than sliders.

Placement of EQ in a distortion signal processing chain affects the
basic guitar amp tone. Using a guitar\'s rotary tone control
potentiometer is a form of pre-distortion EQ. Placing an EQ pedal before
a distortion pedal or before a guitar amp\'s built-in preamp distortion
provides preliminary control of the preamp distortion voicing.

For more complete control of preamp distortion voicing, an additional EQ
pedal can be placed after a distortion pedal; or, equivalently, the
guitar amp\'s tone controls, after the built-in preamp distortion, can
be used. An EQ pedal in the amp\'s effects loop, or the amp\'s tone
controls placed after preamp distortion, constitutes post-distortion EQ,
which finishes shaping the preamp distortion and sets up the power-tube
distortion voicing.

As an example of pre-distortion EQ, Eddie Van Halen places a 6-band MXR
EQ pedal before the Marshall amplifier head (pre-distortion EQ). Slash
places a Boss GE-7, a 7-band EQ pedal, before his Marshall amp. This
technique is similar to placing a Wah pedal before the amp\'s preamp
distortion and leaving the Wah pedal positioned part-way down, sometimes
mentioned as \"fixed wah,\" (pre-distortion EQ), along with adjusting
the amp\'s tone controls (post-distortion EQ).

If a dummy load guitar-amp configuration is used, an additional EQ
position becomes available, between the dummy load and the final
amplifier that drives the guitar speaker. Van Halen used an additional
EQ in this position. This configuration is commonly used with rackmount
systems.

Finally, an EQ pedal such as a 10-band graphic EQ pedal can be placed in
the Insert jack of a mixer to replace the mixer channel\'s EQ controls,
providing graphical control over the miked guitar speaker signal.

Equalization-related effects pedals include Wah, Auto-Wah, and Phase
Shifter. Most EQ pedals also have an overall Level control distinct from
the frequency-specific controls, thus enabling an EQ pedal to act as a
configurable level-boost pedal. Some EQ pedals include:

-   MXR M-108 10-band Equalizer
-   BOSS GE-7 Equalizer

### Wah-wah

!Boss V-Wah pedal

A wah-wah pedal is a moving bandpass filter whose frequency center is
controlled by the musician via a rocker pedal. This filter boosts the
frequencies in the instrument signal around the moving frequency center,
allowing the musician to emphasize different areas of the frequency
spectrum while playing. Rocked to the bass end of the spectrum, a
wah-wah pedal makes a guitar signal sound hollow, without upper
harmonics. On the other end of the sweep, the filter emphasizes
higher-end harmonics and omits some of the low-end \"growl\" of the
natural instrument sound. Rocking the pedal while holding a note creates
a sound that goes from growl to shriek, and sounds like a crying baby,
which is how the effect got its name and also the reason behind the
Crybaby line of wah-wah pedals. The wah-wah pedal, used with guitar, is
most associated with 1960s psychedelic rock and 1970s funk. During this
period wah-wah pedals often incorporated a fuzzbox to process the sound
before the wah-wah circuit, the combination producing a dramatic effect
known as fuzz-wah.

Some wah-wah pedals include:

-   Dunlop Cry Baby
-   VOX V847 Wah Wah
-   Danelectro Trip-L Wah

### Auto-Wah / Envelope Filter

!Musitronics Mu-Tron III
pedal An
Auto-Wah is a Wah-wah pedal without a rocker pedal, controlled instead
by the dynamic envelope of the signal. An auto-wah, also called more
technically an envelope filter, uses the level of the guitar signal to
control the wah filter position, so that as a note is played, it
automatically starts with the sound of a wah-wah pedal pulled back, and
then quickly changes to the sound of a wah-wah pedal pushed forward, or
the reverse movement depending on the settings. Controls include wah-wah
pedal direction and input level sensitivity. This is an EQ-related
effect and can be placed before preamp distortion or before power-tube
distortion with natural sounding results. Auto-Wah pedals include:

-   Electro-Harmonix Q-Tron
-   MXR M-120 Auto Q
-   Keeley Electronics Nova Wah
-   Danelectro French Fries Auto-Wah
-   Mu-Tron III

### Talk Box

Early forms of the talk box, such as the Heil Talk Box, first appeared
in Country Music circles in Nashville in the 1940\',s 1950\'s, and
1960\'s, by artist like swing band pedal steel player Alvino Rey, Link
Wray (\"Rumble\"), Bill West, a Country Music steel guitar player and
husband of Dottie West, and Pete Drake, a Nashville mainstay on the
pedal steel guitar and friend of Bill West. Drake used it on his 1964
album Forever, in what came to be called his \"talking steel guitar.\"
The device used the guitar amplifier\'s output to drive a speaker horn
that pushed air into a tube held in the player\'s mouth, which filters
and thereby shapes the sound leading to a unique effect. The singer and
guitarist Peter Frampton made this effect famous with hit songs such as
\"Do You Feel Like We Do\" and \"Show Me the Way,\" as did Joe Walsh on
\"Rocky Mountain Way.\" On Van Halen\'s cover of \"You Really Got Me\"
Eddie Van Halen uses a talk box after the guitar solo to make a sound
similar to a person having sex. Newer devices, such as Danelectro\'s
Free Speech pedal, use a microphone and vocoder-like circuit to modulate
the frequency response of the guitar signal. Some Talk Boxes include:
The Dunlop Heil Talk Box, Rocktron Banshee, and Peter Frampton\'s own
company,Framptone.

## Volume-related effects

### Volume pedal

A Volume pedal is a volume potentiometer that is tilted forward or back
by foot. A volume pedal enables a musician to adjust the volume of their
instrument while they are performing. Volume pedals can also be used to
make the guitar\'s notes or chords fade in and out. This allows the
percussive plucking of the strings to be softened or eliminated
entirely, imparting a human-vocal sound. Volume pedals are also widely
used with pedal steel guitars in country music. It has also been used to
great effect in rock music; the Pat McGee Band\'s live version of
\"Can\'t Miss What You Never Had\" on General Admission illustrates what
the pedal is capable of. Some volume pedals are:

-   Ernie Ball Stereo Volume Pedal
-   Boss FV-50H Foot Volume
-   VOX V850 Volume Pedal

### Auto-Volume/Envelope Volume

Just as an Auto-Wah is a version of a Wah pedal controlled by the
signal\'s dynamic envelope, there is an envelope-controlled version of a
volume pedal. This is generally used to mimic automatically the sound of
picking a note while the guitar\'s volume knob is turned down, then
smoothly turning the knob up, for a violin-like muted attack. An example
is:

-   Boss SG-1 Slow Gear

### Tremolo

Tremolo is a regular and repetitive variation in gain for the duration
of a single note, which works like an auto-volume knob; this results in
a swelling or fluttering sound. This effect is very popular in
psychedelic and trip-hop music. The speed and depth of the flutter are
usually user-controlled.This is a volume-related effects pedal. This
effect is based on one of the earliest effects that were built into
guitar amplifiers. Examples include:

-   Demeter TRM-1 Tremulator
-   Boss TR-2 Tremolo
-   Electro-Harmonix Worm
-   Line 6 Tap Tremolo
-   Danelectro Cool-Cat Tremolo

### Compressor

!Marshall ED-1 Compressor effects
pedal A
compressor acts as an automatic volume control, progressively decreasing
the output level as the incoming signal gets louder, and vice versa. It
preserves the note\'s attack rather than silencing it as with an
Envelope Volume pedal. This adjustment of the volume for the attack and
tail of a note evens out the overall volume of an instrument.
Compressors can also change the behaviour of other effects, especially
distortion. when applied toward the guitar, it can provide a uniformed
sustained note; when applied to instruments with a normally short
attack, such as drums or harpsichord, compression can drastically change
the resulting sound. Another kind of compressor is the optical
compressor which uses a light source (LED or lamp) to compress the
signal.

Some compressor pedals are:

-   Boss CS-3 Compression Sustainer
-   MXR M-102 DynaComp
-   Diamond Compressor (optical compressor)
-   Line 6 Constrictor
-   T-Rex Engineering\'s CompNova
-   Electro-Harmonix Black Finger (optical compressor)
-   Aphex Punch Factory Optical Compressor
-   TC Electronic Hypergravity Compressor (parallel compressor)

## Time-based effects

### Delay/Echo

!Boss DD3 digital delay
pedal
A Delay or Echo pedal creates a copy of an incoming sound and slightly
time-delays it, creating either a \"slap\" (single repetition) or an
echo (multiple repetitions) effect. Delay pedals may use either analog
or digital technology. Analog delays often are less flexible and not as
\"perfect\" sounding as digital delays, but some guitarists argue that
analog effects produce \"warmer\" tones. Early delay devices actually
used magnetic tape to produce the time delay effect. U2\'s guitarist,
The Edge, is known for his extensive use of delay effects. Some common
Delay pedals are:

-   Boss DD-6 Digital Delay
-   Boss DD-20 Giga Delay
-   Line 6 DL-4 Delay Modeler
-   Line 6 Echo Park
-   T-Rex Engineering\'s Replica
-   TC Electronic Flashback Delay
-   Danelectro FAB Echo

Another technology that is used in Delay units is a feedback circuit,
consisting of a tracking oscillator circuit to hold a note of the last
interval, and after amplifying the signal, send it back to the input
side of the delay. While it was first associated with Boss DF-2 Super
Feedbacker & Distortion, currently, the signal feedback circuit is
employed by Delay pedals, and if used under \"hold\" mode (As in Boss
DD-3) it will provide a sustain effect instead of a simply delay effect.

### Looping

Extremely long delay times form a looping pedal, which allows performers
to record a phrase or passage and play along with it. This allows a solo
performer to record an accompaniment or ostinato passage and then, with
the looping pedal playing back this passage, perform solo improvisations
over the accompaniment. The guitarist creates the loop either on the
spot or it is held in storage for later use (as in playback) when
needed. Some examples of loops effects are:

-   Boss RC-1 & RC-3 Loop Stations
-   Boss RC-300 Loop Station
-   DigiTech JamMan Looper
-   Boomerang Looper
-   TC Electronic Ditto

### Reverb

!DigiTech DigiDelay effects
pedal Reverb
is the persistence of sound in a particular space after the original
sound is removed. When sound is produced in a space, a large number of
echoes build up and then slowly decay as the sound is absorbed by the
walls and air, creating reverberation, or reverb. A plate reverb system
uses an electromechanical transducer (actuator), similar to the driver
in a loudspeaker, to create vibration in a plate of sheet metal. A
pickup captures the vibrations as they bounce across the plate, and the
result is output as an audio signal. A spring reverb system uses a
transducer at one end of a spring and a pickup at the other, similar to
those used in plate reverbs, to create and capture vibrations within a
metal spring. Guitar amplifiers frequently incorporate spring reverbs
due to their compact construction. Spring reverberators were once widely
used in semi-professional recording due to their modest cost and small
size. Due to quality problems and improved digital reverb units, spring
reverberators are declining rapidly in use. Digital reverb units use
various signal processing algorithms in order to create the reverb
effect. Since reverberation is essentially caused by a very large number
of echoes, simple DSPs use multiple feedback delay circuits to create a
large, decaying series of echoes that die out over time.

Examples of reverb pedals include:

-   DigiTech DigiDelay
-   Electro-Harmonix Holy Grail
-   Boss RV-5 Digital Reverb
-   Line 6 Verbzilla

## Modulation-related effects

### Rotary Speaker

Before such effects are available electronically, these are accomplished
by the use of Rotary speakers, by spinning the speakers and/or place a
rotating baffle in front of it. This creates a doppler effect, and
depend on the speed of the rotation, translate into phasing, flanging,
chorus, vibrato, or even tremolo.

-   Leslie Speakers: This is a unit that contains a bass speaker that
    blare into a rotating baffle, and a horn speaker that rotate like a
    siren. Originally designed for Hammond organs, they are also favored
    by guitarist; some say that no electronic effects can duplicate its
    sounds.
-   Fender Vibratone: This is a simplified version of Leslie Speaker,
    containing only a 10\" speaker that blare into a rotating baffle.

All the electronic-based effects can duplicate the sound of a rotating
speakers, as all the following effects differ based on speed, volume,
and modulation. In fact, it is not uncommon for a pedal to be capable of
doing two or more of modulation effects.

### Phase Shifter (Phaser)

!Digitech Hyper Phase effects
pedal

A Phase Shifter creates a complex frequency response containing many
regularly-spaced \"notches\" in an incoming signal by combining it with
a copy of itself out of phase, and shifting the phase relationship
cyclically. The phasing effect creates a \"whooshing\" sound that is
reminiscent of the sound of a flying jet. This effect dominates the
sound in the song Star Guitar by Chemical Brothers. The song was not
played with any guitars but you can hear the phasing effect. The
instrument being phased was actually a synthesizer. Some electronic
\"rotating speaker simulators\" are actually phase shifters. Phase
shifters were popular in the 1970s, particularly used with electric
piano and funk bass guitar. The number of stages in a phase shifter is
the number of moving dips in the frequency response curve. From a sonic
perspective, this effect is equalization-oriented. However, it may be
derived through moderate time-based processing. Some phaser pedals
include:

-   MXR M-101 Phase 90
-   BOSS PH-3 Phase Shifter
-   Electro-Harmonix Small Stone
-   Moog\] MF-103 12 Stage Phaser
-   DigiTech Hyper Phase

### Vibe (Univibe)

A Vibe or Univibe pedal reproduces the sound of a rotating speaker by
synchronizing volume oscillation, frequency-specific volume oscillation,
vibrato (pitch wavering), phase shifting, and chorusing in relation to a
non-rotating speaker. The modulation speed can be ramped up or down,
with separate speeds for the bass and treble frequencies, to simulate
the sound of a rotating bass speaker and a rotating horn. This effect is
simultaneously a volume-oriented effect, an equalization-oriented
effect, and a time-based effect. Furthermore, this effect is typically
related to chorus. Some vibe pedals also include an overdrive effect,
which allows the performer to add \"tube\"-style distortion. This effect
is the most closely related to a rotary speaker. Some Vibe-only pedals
include:

-   BBE Soul Vibe
-   Voodoo Lab Microvibe

Some vibe-chorus pedals include

-   Dunlop Univibe
-   Dunlop Rotovibe
-   BBE Mind Bender

### Vibrato

A vibrato pedal cyclically changes the pitch of the signal, giving the
impression that the guitar is out of tune. The depth of the effect, the
speed and the overall level of the effect can be controlled by
potentiometers. Although similar in name and able to achieve similar
sounds at high speed settings, a vibrato is different from a Vibe pedal.

Examples of vibrato-only pedals:

-   TC Electronic Shaker Vibrato
-   Malekko Omicron vibrato
-   Subdecay Siren pitch vibrato
-   Zvex Verter Instant LoFi Junky
-   Boss VB-2w Vibrato

Some chorus and modulation pedals inclue a vibrato section that can be
combined with chorus, vibe or rotary.

### Flanger

A Flanger simulates the sound effect originally created by momentarily
slowing the tape during recording by holding something against the
flange, or edge of the tape reel, and then allowing it to speed up
again. This effect was used to simulate passing into \"warp speed,\" in
sci-fi films, and also in psychedelic rock music of the 1960s. Flanging
has a sound similar to a phase-shifter, but different, yet is closely
related to the production of chorus.

The first pedal-operated flanger designed for use as a guitar effect was
designed by Jim Gamble of Tycobrahe Sound Company in Hermosa Beach, CA,
during the mid 1970s. Last made in 1977, the existing \"Pedalflangers\"
appear occasionally on eBay and sell for several hundred dollars. A
modern \"clone\" of the Tycobrahe Pedalflanger is sold by Chicago
Iron.Famous users of this Flanger effect include Randy Rhoads and Eddie
Van Halen, coincidentally they both used the MXR M-117R flanger and
Eddie Van Halen even has his own signature model now.

Examples:

-   Boss BF-3 Stereo Flanger
-   Line 6 Liqua Flange
-   MXR M-117R Flanger
-   Danelectro FAB Flange
-   Electro Harmonix Deluxe Electric Mistress

!Ibanez CF7 chorus/flanger effects
pedal

### Chorus

Chorus splits your guitars signal in two, then second signals pitch is
then delayed and/or modulated in pitch and mixed back in with the dry
signal. The effect sounds like several guitarists playing the same thing
at the same time resulting in a wide swelling sound. Some common chorus
pedals are:

-   Boss CE-1 Chorus Ensemble (the original chorus effect pedal, and
    first device released by Boss)
-   Boss CH-1 Super Chorus
-   Electro-Harmonix Small Clone
-   Ibanez CF-7 Chorus/Flanger
-   Line 6 Space Chorus
-   MXR M-134 Stereo Chorus
-   TC Electronic Stereo Chorus /Flanger /Pitch Modulator
-   Danelectro FAB Chorus

### Rotary Speaker Simulator

Despite the numerous different analog devices, it is very rare for them
to be able to duplicate all aspects of a Leslie speaker. Thus, Rotary
Speaker Simulator are always going to be digital, utilizing modelling
algorithms to model the relations between the rotating horns and bass
baffle. And how the sound bounce around the cabinet. As Leslie also have
an amplifier section, most of these typically have overdrives to
simulate that aspect. Some of these pedals can even accept keyboard\'s
input.

-   Boss RT-20 Rotary Ensemble Pedal: This is one of the few pedals that
    is capable of modelling all aspect of a Leslie Speaker.
-   Line 6 Rotomachine: Also a modelling pedal, it is available in a
    compact pedal size.
-   DLS Roto-Sim: Hybrid of analog with DSP modelling.

## Pitch-related effects

### Pitch Shifter/harmonizer

**Pitchshifters** change the pitch of the note played via a
user-specified amount. The range of pitch deviation depends on the
equipment used, but many pedals are capable of raising and lowering the
pitch two octaves above and below the fundamental
pitch. The amount of pitch deviation can be set or controlled via a foot
pedal (which typically offers smooth, continuous pitch control).
Typically, such function will be used with the original signal,
resulting in a **Harmonizer**: the pitch is altered and combined with
the original pitch to create two or more note harmonies. These harmonies
are typically programmed in discrete integer
multiples of the fundamental tone. When used with an expression pedal,
it provides a smooth, abeit slightly digital, bend-like effect. Pitch
shifters can also be used to electronically \"detune\" the instrument.
Some examples are:

-   Digitech Whammy
-   Boss PS-5 Super Shifter
-   Electro Harmonix Harmonic Octave Generator

### Octaver

!Electro-Harmonix Polyphonic Octaver Generator effects
pedal
An Octaver mixes the input signal with a synthesised signal whose
musical pitch is an octave lower or higher than the original. Effects
that synthesize intervals besides octaves are referred to as harmonizers
or pitch shifters. These are frequently used in bands without a bass
player. Octave Up pedals include:

-   Ampeg Scrambler
-   Electro Harmonix POG (Polyphonic Octave Generator)

Octave Down pedals include:

-   Boss OC-3 Super Octave
-   Electro-Harmonix Octave Multiplexer

### Octave fuzz

!MXR M-103 Blue Box (octave down fuzz
pedal)")
An Octave fuzz is a fuzz with an analog octave (up or down). The Octavia
is one of the first octave pedals ever produced. Unlike octavers, the
level of the octave cannot be controlled separately from the fuzz:
increasing the gain makes the octave louder.

Octave up fuzzes include:

-   Roger Mayer Octavia
-   Chicago Iron Tycobrahe Octavia
-   Catalinbread *Octapussy*
-   Electro Harmonix Octavix
-   Fender Blender
-   Foxx *Tone Machine*

Octave down fuzzes include:

-   MXR M-103 Blue Box

## Other effects

### Feedbacker/Sustainer

While audio feedback in general is undesirable due to the high frequency
overtone, when controlled properly, it can provide true sustain of the
sound (instead of using a distortion/compressor to make quiet notes
louder, or a feedback of a signal in a circuit as in a delay unit).
Several approaches have been used to produce guitar feedback effects,
which sustain the sound from the guitar:

-   The most primitive form, as used by Jimi Hendrix, is to use the
    feedback created when the guitar is played in front of a
    loudspeaker.
-   The neck pickup is used as a driver to push the strings based on the
    bridge pickup, such as the Sustainiac Sustainer and Fernandes
    Sustainer.
-   A string driver can be mounted on a stand as in the Vibesware Guitar
    Resonator, which is driven by the selected guitar pickup(s).
    Feedback start, stop and harmonics can be controlled here by
    positioning the drivers distance to the strings and the position
    along the guitar neck while playing.
-   A signal amplifier that powers a headstock transducer, which in turn
    send feedback vibration down the string, as in Sustainiac\'s Model
    C.
-   A handheld string driver can contain a pickup and driver, as in the
    EBow.
-   A dedicated high-gain guitar amp can be used in the control room,
    without a microphone, as a footswitch-controlled string feedback
    driver. The microphone is placed on the speaker cabinet of the main
    guitar amp in the isolation booth or live room.

### Switcher/Mixer (or \"A/B\" pedal)

A switcher pedal (also called an \"A/B\" pedal) enables players to run
two effects or two effects chains in parallel, or switch between two
effects with a single press of the pedal.

Some switcher pedals also incorporate a simple mixer, which allows
mixing the dry guitar signal to be mixed with an effected signal. This
is useful to make overly processed effects more mild and natural
sounding. Examples of the use of the mixer function include:

-   A wah can be mixed with dry guitar to make it more mild and
    full-bandwidth, with less volume swing.
-   A compressor can be mixed with dry guitar to preserve the natural
    attack of the dry signal as well as the sustain of the compressor.
-   Two overdrive pedals can be blended together.
-   A strong phaser effect can be mixed with dry guitar to make it more
    subtle and musical.

Some examples of switcher pedals include:

-   Dunlop A/B pedal
-   Loop Master

Some examples of Switcher/mixer pedals include:

-   BOSS LS-2 Line Selector

### Noise Gate

A noise gate allows a signal to pass through only
when the signal\'s intensity is above a set threshold, which opens the
gate. If the signal falls below the threshold, the gate closes, and no
signal is allowed to pass. A noise gate can be used to control noise.
When the level of the \'signal\' is above the level of the
\'noise\', the threshold is set above the level of
the \'noise\' so that the gate is closed when there is no \'signal\'. A
noise gate does not remove noise from the signal: when the gate is open,
both the signal and the noise will pass through.

Noise gates are also used as an effect to modify the envelope of
signals, removing gradual attacks and decays.

Examples of noise gate pedals include:

-   BOSS NS-2 Noise Suppressor
-   MXR M-135 Smart Gate

### Boosters

There are three types of boosters.

-   The first are signal boosters. These give a gain boost to the signal
    running through it and appear to make the guitar louder. They are
    known as **clean boosts**.
-   The second are frequency boosters. These are similar to the signal
    boosters but instead of boosting the whole signal, they boost one
    specific frequency range. These include treble boosters.
-   The third are harmonic boosters. These boost certain harmonics
    within the wave and can sometimes give a gritty, octave sound (in
    either direction)

A boost pedal can be used to make the guitar louder (set up last in the
effect chain, often in the effects loop of a distorted amp), or to
increase the gain of an overdriven amplifier. Before distortion, a
booster only increases the saturation, not the volume.

## Bass Effects

### Sound conditioner

Bass effects that condition the sound, rather than changing its
character are called \"sound conditioners.\" Gain booster effects pedals
and bass preamplifier pedals increase the gain (or volume) of the bass
guitar signal. Bass preamplifiers for double basses are designed to
match the impedance of piezoelectric pickups with the input impedance of
bass amplifiers. Some double bass preamplifiers may also provide phantom
power for powering condenser microphones and anti-feedback features such
as a notch filter (see \"Filter-based effects\" section below).

Volume pedals are volume potientiometers set into a rocking foot
treadle, so that the volume of the bass guitar can be changed by the
foot. Compression pedals affect the dynamics (volume levels) of a bass
signal by subtly increasing the volume of quiet notes and reducing the
volume of loud notes, which smooths out or \"compresses\" the overall
sound. Limiters, which are similar to compressors, prevent the upper
volume levels (peaks) of notes from getting too loud, which can damage
speakers. Noise gates remove hums and hisses that occur with distortion
pedals, vintage pedals, and some electric basses.

### Bass Distortion

Bass distortion effects preamplify the signal until the signals\'
waveform \"clips\" and becomes distorted, giving a \"growling\",
\"fuzzy\" or \"buzzing\" sound. Until the late 1980s, distortion effects
designed specifically for electric bass\' low range were not commonly
available in stores, so most electric bass players who wanted a
distortion effect either used the natural overdrive that is produced by
setting the preamplifier gain to very high settings or used an electric
guitar distortion pedal. Using the natural overdrive from an
amplifier\'s preamplifier or a guitar distortion effect has the side
effect of removing the bass\' low range (low-pitched) sounds. When a
low-range note is amplified to the point of \"clipping\", the note tends
to go up an octave to its second harmonic, making deep bass notes sound
\"tinny\".

In the 1990s and 2000s, bass distortion effects became widely available.
These effects contained circuitry which ensured that the low-range bass
signal was maintained in the distorted bass tone. Bass distortion is
used in genres such as metal, thrash, hardcore, and punk.

Bass \"overdrive\" effects use a vacuum tube (or digitally-simulated
tube modelling techniques) to compress the top of the signal\'s wave
form, giving a smoother distorted signal than regular distortion
effects. Regular bass distortion effects preamplify the signal to the
point that it develops a gritty or \"dirty\" tone.

Fuzz bass effects are sometimes created for bass by using fuzzbox
effects designed for electric guitars. Fuzzboxes boost and clip the
signal sufficiently to turn a standard sine wave input into what is
effectively a square wave output, giving a much more distorted and
synthetic sound than a standard distortion or overdrive. Paul McCartney
of The Beatles used fuzz bass on \"Think for Yourself\" in the 1966
album \"Rubber Soul\"

### Filtered based effects

Filter based effects for bass include equalizer, phase shifter, wah and
auto-wah.

A **bass equalizer** is the most commonly used of these three effects.
It adjusts the frequency response in a number of different frequency
bands. While its function is similar to a tone controls on an amplifier,
such as rudimentary \"bass\" and \"treble\" frequency knobs, it allows
for more precise frequency changes. A rack-mounted bass equalizer, for
example, may have ten sliders to control the frequency range encompassed
by a regular \"bass\" frequency knob.

In comparison with an electric guitar equalizer, a bass equalizer
usually has a lower frequency range that goes down to 40 Hz, to
accommodate the electric bass\' lower range. Some bass equalizers
designed for use with extended range basses go even lower, to 20 Hz.
Equalizers can be used to change the tone and sound of the electric
bass. If the instrument sounds too \"boomy\", the bassist can lower the
frequency which is overly resonant, or if there is too much fingernail
or pick noise, the higher frequencies can be reduced.

**Notch filters** (also called band-stop filters or band-rejection
filters) are sometimes used with double basses. Notch filters are
filters that allow most frequencies to pass through unaltered, while
attenuating those in a specific range to very low levels. Notch filters
are used in instrument amplifiers and preamplifiers for acoustic
instruments such as acoustic guitar, mandolin, and bass instrument
amplifiers to reduce or prevent feedback. While most notch filters are
set manually by the user, there are also automatic notch filters which
detect the onset of feedback and notch out the frequency before damaging
feedback begins.

**Bass Phase Shifters** create a complex frequency response containing
many regularly-spaced \"notches\" in an incoming signal by combining it
with a copy of itself out of phase, and shifting the phase relationship
cyclically. The phasing effect creates a \"whooshing\" sound that is
reminiscent of the sound of a flying jet.

### Bass chorus

**Bass chorus** effects use a cycling, variable delay time that is short
so that individual repetitions are not heard. The result is a thick,
\"swirling\" sound that suggests multiple instruments playing in unison
(chorus) that are slightly out of tune. Bass chorus effects were more
common in the late 1980s, when manufacturers such as Peavey included
chorus effects in its bass amplifiers. In the 1990s and 2000s, more
sophisticated bass chorus effects devices were created which only apply
the swirling chorus effect to the higher parts of the bass tone, leaving
the instrument\'s low fundamental untouched.\[5\]

## Multi-Effects unit

A multi-FX unit is a single effects device that can perform several
guitar effects simultaneously. Such devices generally use digital
processing to simulate many of the above-mentioned effects without the
need to carry several single-purpose units. In addition to the classic
effects, most have amplifier/speaker simulations not found in analog
units. This allows a guitarist to play directly into a recording device
while simulating an amplifier and speaker of his choice.

!Boss GT-3 multi-effects
unit

A typical digital multi-effects pedal is programmed, with several memory
locations available to save custom user settings. Many lack the
front-panel knobs of analog devices, using buttons instead to program
various effect parameters. Multi-effects devices continue to evolve,
some gaining MIDI or USB interfaces to aid in programming. Examples
include:

-   Tech 21 Sans Amp - A line of analog effects with distortion and
    speaker simulation capability.
-   Line 6 POD XT Live
-   Behringer V-Amp Pro
-   DigiTech RP series
-   DigiTech GNX series
-   Boss ME-20, ME-50, GT-6, GT-8
-   Zoom G2, G3, G5 series
-   Vox Tonelab series
-   Roland VG series
-   Korg AX series

The quality of sound that is a major feature of separate pedals can
never be matched by a multi-effects unit but they are ideal for a
guitarist on a budget.

