Effects unit facts for kids
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An effects unit (also called an effects processor or effects pedal) is an electronic device that changes how a musical instrument or other sound source sounds. It does this by processing the audio signal. Think of it like adding a filter or a special effect to a photo, but for sound!
Many common effects exist. For example, distortion makes electric guitars sound "gritty" or "rock and roll." Volume pedals and compressors change how loud or soft a sound is. Wah-wah pedals and graphic equalizers change the "color" of the sound by adjusting different frequencies. Other effects create swirling sounds like chorus or flangers. Some change the pitch, while others create echoes like reverb and delay.
Most modern effects use solid-state electronics or digital signal processors. Older effects, like Leslie speakers, might use mechanical parts or vacuum tubes. Effects often come as stompboxes, which sit on the floor and are turned on or off with your foot. They can also be built into guitar amplifiers, instruments like the Hammond B-3 organ, or larger tabletop units for DJs. Many are also used as audio plug-ins in computer music programs.
Musicians, audio engineers, and record producers use effects during live shows or in the studio. They are most often used with electric guitars, bass guitars, or electronic keyboards. However, you can use effects with almost any sound, including acoustic instruments, drums, and even voices!
Contents
Understanding Effects: Key Terms
An effects unit has many names, like "effect box" or "effects pedal." The short form "F/X" or "FX" is also common. A pedal you control with your foot is often called a "stompbox."
When sound goes into an effects unit without any changes, it's called "dry." After the effect changes the sound, it's called "wet."
Musicians who use many pedals often put them on a guitar pedalboard. This makes it easier to set up and pack away their gear. It also protects the pedals when traveling. If a musician has many effects in a rack mounted case, it's called an "effects rack" or "rig."
Different Types of Effects Units
Effects units come in various shapes and sizes. They can be used for live shows or in the studio. Some use analog circuits, some use digital electronics, and some use both! During a live show, the effect connects to your instrument's sound path. In the studio, the sound from an instrument or mixer goes into the effect.
Stompboxes: Pedals for Your Feet
Stompboxes are small boxes, usually made of plastic or metal. They sit on the floor so you can press a footswitch to turn them on or off. Most stompboxes are rectangular. They usually have one footswitch, a few knobs to control the sound, and a light to show if the effect is on.
For example, a distortion pedal might have knobs for how much distortion, the tone, and the overall volume. A chorus effect pedal might have knobs for how deep and fast the effect is. Some stompboxes are more complex, with many footswitches, knobs, and even small screens.
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An effects chain is when you connect two or more stompboxes together. This creates a path for your sound. When a pedal is off, the sound usually goes straight through it without being changed. This lets musicians combine effects in many ways without having to plug and unplug cables during a performance.
Musicians often put compression, wah, and overdrive pedals at the start of the chain. Chorus, flanger, and phase shifter pedals usually go in the middle. Time-based effects like delay and reverb are often at the end. If you use many effects, you might get unwanted noise. A noise gate pedal can help reduce this noise.
Rackmount Units: For Studios and Big Stages
Rackmount effects units are larger, flat metal boxes. They are designed to be screwed into a special frame called a 19-inch rack. These racks are standard in the music technology world. Rackmount units are usually 19 inches wide and come in different heights.
A rackmount unit might have the same circuits as a stompbox, but often they are more complex. They usually contain several different types of effects. You control them with knobs and buttons on the front, or sometimes with a separate foot controller.
Rackmount effects are most common in recording studios and for front of house live sound mixing at concerts. Musicians might use them on stage to hold many effects and other gear. They are often kept in strong cases called "road cases" for protection during travel.
Multi-Effects and Tabletop Units
A multi-effects (MFX) device is a single unit that contains many different electronic effects. These devices let you save combinations of effects as "presets." This means a musician can quickly switch between different sounds during a show. Multi-effects units usually include distortion, chorus, flanger, phaser, delay, looper, and reverb.
Pedal-style multi-effects can be simple, with just a couple of effects, or large and expensive, with many pedals and knobs. Rack-mounted multi-effects units can be placed in the same rack as other audio equipment.
A tabletop unit is a type of multi-effects device that sits on a desk. You control it with your hands. The Pod guitar amplifier modeler is an example. Digital effects for DJs are often tabletop models, so they can be placed next to a DJ mixer and turntables.
Built-in Effects: Part of Your Gear
Effects are often built right into instrument amplifiers and even some instruments. Electric guitar amplifiers often have built-in reverb, chorus, and distortion. Acoustic guitar and keyboard amplifiers usually have reverb. Some acoustic amps also have chorus, compression, and equalization. Older guitar amps often had tremolo and vibrato effects.
Built-in effects might offer less control than separate pedals. For example, a bass amp might just have an on/off switch for its compressor. A separate pedal would give you more ways to adjust the sound.
Instruments with built-in effects include Hammond organs, electronic organs, electronic pianos, and digital synthesizers. These often have reverb, chorus, and vibrato. Some acoustic-electric and electric guitars also have built-in preamps or equalizers.
A Brief History of Sound Effects
The first sound effects were created in recording studios. Engineers would place microphones in special echo chambers to make music sound like it was played in different rooms. In the 1940s, musicians like Les Paul started experimenting with tape recorders to create echo and unique sounds.
In 1941, DeArmond released the first stand-alone effects unit, the Model 601 Tremolo Control. Early stand-alone effects were often big and expensive. The first popular portable effect was the 1958 Watkins Copicat, a tape echo effect made famous by the band The Shadows.
Effects in Amplifiers
Effects built into tube-powered guitar amplifiers were the first effects musicians used regularly outside the studio. From the late 1940s, Gibson started adding vibrato to their amps. The 1950 Ray Butts EchoSonic amp had a tape echo, which became popular with guitarists like Chet Atkins. Fender also made amps with tremolo and vibrato.
Distortion wasn't planned at first. Guitarists found they could get a "warm" distorted sound by turning their tube amplifiers up very loud. In the 1950s, musicians like Willie Johnson and Chuck Berry started experimenting with this sound. Link Wray's 1958 song "Rumble" inspired many young musicians to explore distortion. By 1966, Marshall Amplification was making amps known for their distorted "crunch" sound.
The Rise of Stompboxes
The invention of the transistor made it possible to create small, portable stompboxes. Transistors were smaller and more stable than vacuum tubes. The first transistorized guitar effect was the 1962 Maestro Fuzz Tone pedal. It became hugely popular after The Rolling Stones used it in their 1965 hit "(I Can't Get No) Satisfaction".
In 1967, Warwick Electronics made the first wah-wah pedal. That same year, Roger Mayer created the first octave effect, which Jimi Hendrix used on songs like "Purple Haze". In 1968, Univox started selling the Uni-Vibe pedal, which mimicked the sound of Leslie rotating speakers. Jimi Hendrix and Robin Trower loved this pedal. In 1976, Boss Corporation released the CE-1 Chorus Ensemble, the first chorus pedal. By the mid-1970s, many solid-state effects pedals were available.
In the 1980s, digital rackmount units became popular. Musicians often recorded "dry" tracks and added effects later. However, the success of Nirvana's 1991 album Nevermind brought stompboxes back into fashion. Some grunge guitarists would connect several fuzz pedals to a tube amplifier. Musicians like J Mascis of Dinosaur Jr. continued to use analog effects pedals throughout the 1990s.
Effects pedals have even been celebrated in song titles and band names, showing their importance in music history!
How Effects Change Your Sound
Musicians use many different techniques to change their sound. Here are some of the most common types of effects.
Distortion Effects: Adding Grit and Warmth
Distortion, overdrive, and fuzz effects make a sound "warm," "gritty," or "fuzzy." They do this by changing the shape of the sound's waveform. This adds new sounds called harmonics or inharmonic overtones. Distortion effects are sometimes called "gain" effects because early distorted guitar sounds came from turning up tube amplifiers very loud.
- Distortion pedals create a strong, often "hard" clipping sound.
- Overdrive pedals create a "soft" distortion, similar to a tube amp turned up. They can sound clean at low volumes and distorted at higher volumes.
- Fuzz pedals clip the sound until it's almost a square wave, making a very distorted or "fuzzy" sound. The The Rolling Stones' song "(I Can't Get No) Satisfaction" famously used a fuzz effect.
Some popular distortion pedals include the Boss DS-1 Distortion and Ibanez Tube Screamer. Famous fuzz pedals include the Arbiter Fuzz Face and Electro-Harmonix Big Muff. While mostly used with guitars, distortion effects can also be used with keyboards, drums, and vocals.
Dynamics Effects: Controlling Volume
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Dynamics effects change the volume of an instrument. These were some of the first effects available to guitarists.
- Boost/Volume Pedal: A boost pedal makes your instrument louder. Musicians use them to increase volume for solos or to prevent sound loss in long effects chains. A Treadle-based volume pedal lets you adjust volume with your foot.
- Compressor: Compressors make loud sounds quieter and quiet sounds louder. They "compress" the range between the loudest and softest parts of a sound. This helps to make the volume more even.
- Noise gate: Noise gates reduce unwanted hum, hiss, or static. They turn down the volume when the sound falls below a certain level. This makes quiet sounds even quieter. A famous example is the gated drum effect in Phil Collins' song In the Air Tonight.
Filter Effects: Shaping the Sound's Color
Filter effects change the frequency content of a sound. They can make certain frequencies stronger or weaker.
- Equalizer: An equalizer lets you boost or cut specific frequency areas. Simple home stereos have bass and treble controls. Professional equalizers offer much more detailed control. They help engineers remove unwanted sounds or make an instrument stand out.
- Talk box:
A talk box sends your instrument's sound into your mouth through a tube. You can then shape the sound into words by moving your mouth. This makes it sound like your guitar is "talking." Famous songs using a talk box include Bon Jovi's "Livin' on a Prayer" and Peter Frampton's "Show Me the Way".
Peter Frampton using a Talk box. - Wah-wah: A wah-wah pedal creates vowel-like sounds (like "wah-wah"). You control it with a foot pedal that changes the sound's frequency spectrum. Wah-wah pedals are very popular with funk and rock guitarists.
- Auto-wah (or envelope filter): This effect changes the filter based on how loud you play. It's often used in funk and reggae music.
Modulation Effects: Creating Movement and Swirl
Modulation effects change a sound over time to create movement. Some split the sound into two, change one part, and then mix them back together.
- Chorus: Chorus pedals mimic the sound of many voices or instruments playing together. They split the sound, add a slight delay and vibrato to one part, and then mix it back with the original. Nirvana's "Come As You Are" features a well-known chorus effect.
- Flanger: A flanger creates a "whooshing" or "jet plane" sound. It adds a slightly delayed version of the sound to the original, creating a unique effect. Famous uses include The Police's "Walking on the Moon" and Van Halen's "Ain't Talkin' 'Bout Love".
- Phaser: A phaser creates a rippling sound by splitting the audio signal and changing the phase of one part. The keyboard parts in Billy Joel's "Just the Way You Are" use a phaser.
- Tremolo: A tremolo effect creates a variation in the volume of a sound. It makes the sound get louder and softer rhythmically. The guitar intro in The Rolling Stones' "Gimme Shelter" uses a tremolo effect.
- Vibrato: Vibrato effects create slight, rapid changes in pitch. This mimics how singers or violinists naturally vary a note. Guitarists sometimes confuse vibrato with tremolo. A "tremolo arm" on a guitar actually creates vibrato!
Pitch and Frequency Effects: Changing Notes
A pitch shifter (or "octaver") changes the pitch of each note you play by a set interval. For example, it can make every note sound an octave higher or lower. A guitarist could use one to play notes usually found on a bass guitar.
A harmonizer is a special type of pitch shifter. It combines the changed pitch with the original pitch to create a two or three-note harmony.
The DigiTech Whammy, released in 1989, was a popular digital pitch shifter. It creates a unique "wobbly" sound. Musicians like Tom Morello of Rage Against the Machine and David Gilmour of Pink Floyd have used it.
Time-Based Effects: Echoes and Loops
Time-based effects delay the sound, add reverb, or let you record and play back loops.
- Delay/Echo: Delay units create an echo effect by adding a copy of the original sound a short time later. This can be a single echo (called "slapback") or many echoes. The lead guitar in U2's "Where the Streets Have No Name" famously uses delay.
- Looper Pedal: A looper pedal lets you record a short musical phrase and play it back. You can create loops on the spot during a performance. A singer-guitarist can record backing chords, loop them, and then sing and play a guitar solo over them. Some loopers let you layer many loops to create the sound of a full band.
- Reverb: Reverb units make your sound seem like it's in a big space, like a hall or a cathedral. They do this by creating many echoes that slowly fade away. Early reverb effects were made by sending sound into a reflective room and recording it. Spring reverb systems, often found in guitar amplifiers, use a spring to create vibrations. Digital reverb uses computer programs to create these effects. Rockabilly and surf guitar music often use a lot of reverb.
Feedback and Sustain Effects
Audio feedback happens when amplified sound is picked up by a microphone or guitar pickup and played back through an amplifier, creating a loop of sound. While feedback is usually avoided, electric guitar players sometimes intentionally create it. They stand in front of their loud guitar amplifier to make sustained, high-pitched sounds. Guitarists like Jimi Hendrix pioneered this creative use of feedback in the 1960s.
The EBow is a small, handheld device that makes a guitar string vibrate continuously. This creates a sound similar to a cello or violin. It uses a special circuit to make the string resonate. Later EBow models can produce both sustain and overtone feedback.
Many compressor pedals are also called "sustainer pedals." When a note is played, it naturally loses energy and volume. A compressor pedal boosts the sound's signal, making the note last longer. Combined with distortion and a loud amplifier, this can create almost endless sustain.
Other Cool Effects
- Guitar amplifier modeling: This digital effect copies the sound of different amplifiers, especially vintage tube amps and famous speaker cabinets. It can even simulate different types of speakers and how microphones are placed.
- Pitch correction/Vocal effects: These effects use computer programs to fix singing that is slightly out of tune. They can also create unique vocal sounds, like the famous Autotune effect.
- Simulators: Simulators let electric guitars sound like other instruments, such as acoustic guitars, electric basses, or even sitars. A "de-fretter" effect can make a bass guitar sound like a fretless bass.
- Rotary speakers: These special speakers rotate to create unique audio effects. The rotating baffle creates a chorus-like sound. They are most famous for being used with the Hammond organ but are also used with other instruments and vocals.
Bass Effects: For Low Sounds
Bass effects are electronic units made for the low sounds of an electric bass or an upright bass. Examples include fuzz bass and bass chorus. Some bass amplifiers have built-in effects like overdrive or chorus. Upright bassists often use a bass preamplifier to boost and shape their sound.
Boutique Pedals: Unique and Handcrafted
Boutique pedals are made by smaller, independent companies. They are often produced in limited numbers and sometimes even hand-made. These pedals can be more expensive than mass-produced ones. They often use high-quality parts, have unique designs, and sometimes feature hand-painted artwork. Some boutique companies focus on recreating the sound of classic or vintage effects.
Modifying Effects: Customizing Your Sound
There's also a special market for modifying or "modding" effects pedals. People can get custom changes made to their pedals or buy already modified ones. Popular pedals like the Ibanez Tube Screamer and Boss DS-1 are often modified. Common changes include swapping out parts for higher-quality ones or adding new features.
Other Useful Pedals and Rack Units
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Not all stompboxes and rack-mounted devices are effects units. For example, electronic tuner pedals show if your guitar string is too sharp or flat. These tuners usually have an output so you can plug into your amp.
Rackmount power conditioners make sure your equipment gets clean, steady power. A rack-mounted wireless receiver lets a musician move freely on stage without cables. A footswitch pedal, like an "A/B" pedal, can switch your guitar signal between two amplifiers or two guitars.
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Guitar amplifiers and electronic keyboards often come with footswitches to turn their built-in effects (like reverb or distortion) on and off. These footswitches only contain a switch; the actual effect circuit is inside the amp. Some musicians use MIDI controller pedalboards to trigger sounds or control effect settings from their rack units or computers. A pedal keyboard uses pedals to play notes, usually basslines, but it's an instrument, not an effect unit.
Famous Effects Unit Makers
- BJFE/One Control
- Chase Bliss Audio
- Darkglass Electronics
- DOD Electronics
- Dunlop Manufacturing/MXR
- EarthQuaker Devices
- Electro-Harmonix
- Eventide Inc.
- Fulltone
- JHS Pedals
- Keeley Electronics
- Maxon Effects
- Meris
- Mooer Audio
- Morley Pedals
- Roland/Boss Corporation
- Seymour Duncan
- Source Audio
- Strymon
- TC Electronic/Behringer
- Tech 21
- Universal Audio
- Wampler Pedals
- Z.Vex Effects
- Zoom Corporation
See also
In Spanish: Unidad de efectos para niños
- Effects unit § Notes — a list of non-electronic audio effects
- Category:Audio effects
- Frequency divider
- Frequency mixer
- Nonlinear filter
- Outboard gear — effects units used in the context of audio mixing
- Sound effect
- Vintage musical equipment
