Effects device (music)

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In music, an effects device is a device or plug-in for changing an audio signal . This can be done mechanically , electronically , digitally or in any combination. Additional effects are also added to conventional instruments using suitable devices.

Effects devices

An effects device cannot always be clearly assigned to a specific group, as different physical effects are often combined to achieve the desired effect.

Three compressors: at the top two single-channel (mono) compressors, at the bottom a two-channel or stereo compressor

Level-oriented effects devices

Level-oriented effects devices are usually dynamics processors . They use the level as a control signal. The most commonly used are the compressor , limiter, and gate . There are also other level-oriented effects, such as the chopper, tremolo and the transient designer . Effects such as the triggered cross-fading of the signal source onto different output channels (pan flip, ducking) are level-oriented.

Spectral modifying effects devices

This type of effects device makes changes in the frequency range . The spectrum- modifying effect devices include pitch shifter , harmonizer (occasionally also in formant-controllable form), ring modulator , vocoder ( talkbox ), phaser , Leslie loudspeaker and automatic pitch correction or intonator. Simple forms are fixed or variable filters ( equalizer , wah-wah )

Distorting effects devices

Distorters change the signal structure by adding overtones . Distorting effects are on the one hand distortion , fuzz or overdrive , which give the signal a typical sound known from distorted rock guitars through targeted overdriving. On the other hand, this includes the rectifier (not to be confused with rectifier ), the enhancer or the exciter , which enhance the signal in the overtone range without clipping. See also: Bitcrusher .

Two reverb units: Dynacord DRP 20 above, Yamaha SPX 900 below

Delay time-oriented effect devices

With this type of effect device, the change in the sound is produced by mixing the original signal with a delayed double, which, depending on the design , can lead to comb filter effects . The typical delay time-oriented effect devices are the reverb , the delay or echo , the chorus , vibrato and the flanger .

Time-oriented effects devices

Time shifters can be found among the time-oriented effects devices. Another group are sample-based effects devices, for which there are no generalized names. Such devices usually sample (store) the input signal during runtime and reproduce more or less changed time segments from it, which are faded into one another.

Stringed instruments

Boss DS-1 distortion pedal

Electric guitar, electric violin

Guitar effects devices are mostly operated by the guitarist himself during the game (also live). They can therefore be operated with the foot and stand on the floor in front of the guitarist. Therefore, they are often referred to as “floor effects”, “floor kicks” or similar. The term “pedal mine” / “ tell mine ” is also common - the Arbiter Fuzz Face Fuzz was reminiscent of a plate mine in the sixties with its round shape and foot switch .

The term “floor effect” is also used for complex multi-effects with several foot switches, whereas “floor kicks” rather refers to the simpler devices. Depending on the device, the foot control enables the effect to be switched on easily or continuous control using a pedal rocker; z. B. Wah-wah.

As an alternative to the floor effects, there are 19 "effect processors, which usually contain a large number of effects (or of higher quality) and are controlled by the guitarist using MIDI pedals. However, these effect processors are also increasingly found modified as floors Effects again.

Musical effects devices are often used in audio processing. Guitar effects are specially adapted to the needs of guitarists and the typical frequency spectrum of the guitar.

Ibanez CF7 floor effect unit chorus / flanger


Sustainer / Feedbacker Vibesware Guitar Resonator GR-1

Typical effects devices used with guitars are:

more special effects devices:

Old-school effects device use
  • "Envelope Filter", "Synth Wah", "Auto Wah"
  • Looper (sampler, phrase sampler)
  • "Slow Gear" or "Slow Motion" (swelling of the sound like a string instrument) * "Sustainer / Feedbacker" (electromagnetic actuators to excite vibrations in the guitar strings): E-Bow , Fernandes Sustainer, Guitar Resonator
  • Talkbox .

Loop-in path

versatile pedal board

In order to achieve the desired sound, the use of guitar effects requires special arrangements in the signal path. Level-changing effects such as volume pedal, compressor, distortion and wah-wah are usually switched between the guitar and the preamp. This has an influence on the overdrive behavior of the preliminary stage. Linear effects such as reverb, modulation effects and equalizers are usually switched to the loop-in path, i.e. H. between preamp and output stage so that they are not overdriven. This is handled differently depending on the individual use. For example, an equalizer can be switched in front of the preamp to explicitly change the sound of the guitar itself. Modulation and delay effects in the shape of a floor pedal are usually designed to be switched in front of the power amplifier. However, this arrangement requires a parallel or serial loop-in path on the guitar amp itself, which makes the internal amplifier signal between the preamp and output stage available via external connections. A serial loop-in option interrupts the internal signal path and guides the signal through the effect, while a parallel loop-in allows the effect to be added to the amplifier signal.

Electric bass, cello

Effects for electric basses hardly differ from those for electric guitars . However, they are often specially tailored to the low frequency spectrum of the electric bass.

Pedal board

Several effect devices are usually grouped into a pedal board in order to shorten the assembly and dismantling times and to facilitate the overview during operation.

Hammond organ

A typical effects device for the Hammond organ is the Leslie loudspeaker cabinet .

Wind instruments

In brass instruments such as trumpet and trombone , especially in jazz, dampers are used to influence and shape the sound, for example the wah-wah.


  • Hubert Henle: The recording studio manual. 5th edition, GC Carstensen Verlag, Munich, 2001, ISBN 3-910098-19-3
  • Helmuth Lemme: Guitar amplifier sound. 1st edition, Richard Pflaum Verlag, Heidelberg, Munich, 1995, ISBN 3-7905-0717-2
  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich et al. 2006, ISBN 3-446-40198-9 .
  • Rolf Beckmann: Manual of PA technology. Basics, components, practice. 2nd Edition. Elektor-Verlag, Aachen 1990, ISBN 3-921608-66-X .

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