Effects unit
An effects unit, effects processor, or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing.
Not to be confused with Software effect processor.
Common sound effects include distortion/overdrive, often used with electric guitar in electric blues and rock music; dynamic effects such as volume pedals and compressors, which affect loudness; filters such as wah-wah pedals and graphic equalizers, which modify frequency ranges; modulation effects, such as chorus, flangers and phasers; pitch effects such as pitch shifters; and time effects, such as reverb and delay, which create echoing sounds and emulate the sound of different spaces.[1][2]
Most modern effects use solid-state electronics or digital signal processors. Some effects, particularly older ones such as Leslie speakers and spring reverbs, use mechanical components or vacuum tubes. Effects are often used as stompboxes, typically placed on the floor and controlled with footswitches. They may also be built into guitar amplifiers, instruments (such as the Hammond B-3 organ), tabletop units designed for DJs and record producers, and rackmounts, and are widely used as audio plug-ins in such common formats as VST, AAX, and AU.
Musicians, audio engineers and record producers use effects units during live performances or in the studio, typically with electric guitar, bass guitar, electronic keyboard or electric piano. While effects are most frequently used with electric or electronic instruments, they can be used with any audio source, such as acoustic instruments, drums, and vocals.[3][4]
History[edit]
Studio effects and early stand-alone units[edit]
The earliest sound effects were strictly used in studio productions. Microphones placed in echo chambers with specially designed acoustic properties simulated the sound of live performances in different environments. In the mid to late 1940s, recording engineers and experimental musicians such as Les Paul began manipulating reel-to-reel recording tape to create echo effects and unusual, futuristic sounds.[24][25] In 1941, DeArmond released the Model 601 Tremolo Control,[26] the first commercially available stand-alone effects unit. This device produced a tremolo by passing an instrument's electrical signal through a water-based electrolytic fluid.[27] Most stand-alone effects of the 1950s and early 1960s such as the Gibson GA-VI vibrato unit and the Fender reverb box, were expensive and impractical, requiring bulky transformers and high voltages. The original stand-alone units were not especially in-demand as many effects came built into amplifiers. The first popular stand-alone was the 1958 Watkins Copicat, a relatively portable tape echo effect made famous by the British band, The Shadows.[28][29]