Effects
Effects are analogue or digital devices that intentionally change the sound of a signal or recorded audio. This page covers the core and advanced parameters for time-based effects (reverb and delay), modulation effects (vibrato, tremolo, chorus, flange and phaser), distortion, vocal effects (vocoder and talk box) and lo-fi effects.
An effects processor, whether it be in the form of a plugin, a rack-mounted effects unit, a pedal or built into a synthesiser, takes the original sound, changes the sonic quality of the sound (in different ways depending on what the effect is) and then produces an output.
There are two parameters or controls that are present on all effects processors; the wet/dry control and the bypass control.
The wet/dry control determines the balance between the wet (processed) signal and the dry (original) signal in the output signal.
The bypass control allows you to disengage the effect that you’ve just applied so that you can easily compare it to the raw/original sound.
In your DAW, all of these effects can be added either via an insert or via a send. An effect insert will affect only the channel that the plugin is assigned to. On the other hand, you can put an effect on an auxiliary track instead and then send the signal to that track. This is a convenient way of affecting multiple tracks with the same effect, as all of the tracks can be sent to one auxiliary channel and be affected in the same way.
Reverb
Reverb, short for reverberation, is “the ambience found within a sound. Either an acoustic space or an artificially created effect.”
In other words, reverb is the effect of sound being reflected back to a listener’s ears from surrounding objects. An example of reverb in the ‘real world’ would be making a loud sound in a space such as a cathedral or concert hall.
Now imagine shouting into a cave – a second or two later, you hear it echo back again. This is not reverb, but echo. The time between each reflection is 50ms (super fast) or lower for reverb, and any time longer than that is classed as an echo.
The structure of reverb is made up of three parts; the original sound, early reflections (including first reflection) and reverb tail/decay. The reflections arrive at your ears at slightly different times because they are reflecting off different objects at different distances. The waves gradually lose energy the sound decays.
When recording, it is common practice to record in a ‘dead’ room (no reflections or reverb due to absorbent surfaces) because you are less likely to pick up unwanted noise and you are less likely to get phasing issues. The only problem with this is that it can sound unnatural, so that’s where artificial reverb comes in – it puts your sound in a ‘place’. It gives the impression that the musicians are playing in a natural acoustic environment.
Types of reverb
Room: Calculated by algorithms, this effect applies reverb to the signal that you would hear in a typical room. You can change the size of the room by changing the reverb time.
Hall: Also calculated by algorithms, this effect makes it sound as though your signal was recorded in a hall.
Plate: The signal is fed onto a large metal plate via a drive transducer and then picked up again with pickup transducers. Available in plugin form as well as physical plate form.
Spring: Works in a similar way to plate reverb but it’s a suspended spring rather than a plate.
Gated: Reverb tail is cut short by a noise gate, instead of allowing it to naturally decay in amplitude over time.
Reversed: Takes the reverb tail and reverses it.
Reverb Parameters
Reverb time/decay: Determines the time that to takes for the sound to decay. The sound has decayed, or the reverberations have stopped, when the sound pressure level has decreases by 60 dB. This measurements is known as RT60 (reverb time 60db).
Pre-delay: Used to change the time (in milliseconds) between the original sound and the first audible reflections.
Early reflections level: Allows you to change the loudness of the early reflections. The louder they are, the smaller the “room” will seem.
Diffusion: This parameter controls that distance between the early reflections. The higher the diffusion level, the closer the reflections are to one another, creating a thicker sound. A low diffusion level will create a more open sound.
Damping: Increasing the damping level will reduce the level of high frequencies on the reverb tail, therefore making it sound as if the room had softer surfaces (carpets) in it rather than hard surfaces (wood flooring)
High and low frequency attenuation: Allows you to decide which frequencies are affected by the reverb. High frequency dampening comes under this parameter umbrella and attenuates the frequencies of the wet signal at the higher end of the frequency spectrum.
Delay
Delay is “the process of delaying a sound electronically and then playing it back after a fixed period of time. Normally blended with the original signal to create an echo effect.”
While many producers use the words delay and echo interchangeably, echo is actually a type of delay, as not all delays are echos, as you will see from the list below of types of delay.
Types of delay
Single tap: Each tap is a repetition of the original sound. With this delay type, you only get one repetition of the signal.
Multi-tap: This delay type allows you to have multiple taps. On most DAWs you can control how many taps you have and when they occur.
Slapback: A very short singular tap, usually occurring only 40-120 milliseconds after the original sound.
Timed: This type of delay allows you to have control over when/how often a tap occurs. You can set it to a note value so that it plays in time with your track.
Ping pong: This delay bounces across the stereo field, normally starting on the left and then the next tap on the right.
Automatic double tracking (ADT): Not technically a type of delay but useful to know about. It creates the feeling of multiple voices by copying the signal and delaying the copy by between 10-50 milliseconds. This is almost inaudible (as a delay effect) but can help to thicken up a signal.
Parameters
Delay time: The time between each repeat.
Feedback: How many repeats/taps you get.
Tempo sync: Allows you to select which note value you want your delay to sync to. Can be anything from the crotchet beat, to the quaver beat or to a semi-quaver triplet beat.
Delay pan: This parameter allows you to decide from where in the stereo field the delayed signal will come from. Can be automated to created ping-pong delay.
EQ: This control allows you to decide which frequencies of the dry signal are being affected by the delay effect, and by how much. They can either be attenuated or boosted.
Vibrato
Vibrato is “an effect that is created by the modulation of pitch.”
Parameters
Rate: The speed at which the pitch changes.
Depth: The variation in pitch.
It's always good to have an example of each effect from a song that you know so that you can remember what it sounds like. I chose Mac DeMarco’s “Treat Her Better” as my example, but DeMarco uses vibrato on his guitar parts in pretty much all of his songs.
Listen to the guitar part in this song. DeMarco uses a slow vibrato rate on the main guitar part.
Tremolo
Tremolo is “an effect that is created by the modulation of volume.”
Parameters
Rate: the speed at which the volume changes.
Depth: the variation in volume.
In this song, tremolo is used on the lead guitar part.
Chorus
Chorus is “a modulation effect that simulates multiple instruments or voices performing simultaneously by duplicating an audio signal. This creates a ‘shimmering’ or ‘thickening’ effect. One copy of the signal is slightly delayed and is also slightly detuned using an LFO. The wet and dry signals are then recombined."
Put in simpler terms, to create the chorus effect, multiple copies of the original signal are made, delayed, pitch shifted, and mixed back in with the original signal.
Chorus is considered to be a modulation effect because the delay time is modulated by an LFO. Modulation “literally means ‘changing'.” In this context, this means that the delay time (time between original signal and delayed signal) varies.
Parameters
Rate: Measured in Hz, this parameter allows you to control the speed at which the delay time does a full cycle, as shown by the gif above. If you set the rate at 2Hz, the delay would go from zero to the maximum, to the minimum and back to zero twice per second.
Delay: Allows you to set the (average) delay time (in milliseconds)
Depth: Allows you to set the range of delay time (maximum and minimum)
You can hear chorus being used in the first few seconds of this song on the guitar.
Flanger
A flanger is “a modulation based effect that is created by altering the phase relationship between two signals by modulating a short delay. Flanging creates a distinctive tone caused by comb filtering."
A flanger is very similar to chorus because the original signal is duplicated, delayed and then mixed back in with the original signal. However, there are some differences between the two:
The time between the modulated delay signal and the original source signal is smaller in a flanger than in a chorus.
A flanger only has one delayed signal, whereas a chorus may have two or more.
In a flanger, some of the processed signal may be fed back into the processor; this never happens in a chorus.
Chorus also pitch shifts the signal, but this doesn’t happen in a flanger.
Flanger has the same parameters as chorus does.
Here is an example of the use of flanger. Go to 2:42 and listen to the drum solo.
Phaser
A phaser is an “effect that modulates an audio signal in-and-out of phase to create an aurally pleasing effect of certain frequencies being amplified and reduced.”
If you don't know what phase is, read this page first!
The original signal is copied, and this copy is passed through a series of all-pass filters which alter the phase of certain parts of the frequency spectrum. The phase-shifted signal/frequencies can be shifted to varying degrees, as shown by the diagrams above. If the signal was shifted at 180º however, the sound would cancel out and you wouldn’t be able to hear anything.
This phase-shifting around certain frequencies cause notches to form, which are narrow bands of the frequency spectrum that are completely cut/made inaudible. A series of these notches are called a comb filter. An LFO moves the positions of theses notches which is what makes this filter a modulation filter.
The phase difference between the original signal and the phase-shifted signal causes some frequencies to be amplified and some frequencies to be attenuated or cut completely.
Parameters
Rate: Allows you control the speed at which the LFO modulates the notches.
Depth: Allows you to control the degree to which the notches are modulated.
Billy Joel makes use of the phaser on the main piano part in “Just the Way You Are”
Wah-wah
The wah-wah effect is “an effect that is created by the modulation of a band pass filter to adjust the amount of treble/bass within a sound. Commonly adjusted with a foot controller.”
Essentially, the band filter with a medium sized Q value is modulated/moved across the frequency spectrum in a sweeping motion. Surprisingly enough, it creates a wah sound.
Parameters
Rate: The speed at which the filter is modulated.
Depth: The range of the modulation of the filter.
A notable use of wah wah is in Jimi Hendrix’s ‘Voodoo Child’ on the main guitar part.
Distortion
Distortion is when “an audio signal overloads and clips.” Sometimes it is an unwanted sound, but other times it is used for create effect.
Before solid-state amps, pedals and DAW plugins were available, the only way that you could create a distorted sound was to overdrive your amp (tube amp at the time) by setting the gain at a high level so that the sound distorted. It created a good sound but you had to play very loud for it to work, which wasn’t very neighbour or amp friendly.
In the early 60s, after years of producers trying to avoid it, distortion became a popular effect to have on your guitar. “You Really Got Me” by The Kinks was arguably the first commercially successful record that had distortion on the guitar. They achieved this iconic sound by slashing holes in the speaker cones in their amps.
When solid-state amps were invented, they often came with tone control so that you could distort your sound without it having to be horrendously loud. The difference between tube and solid-state amp distortion, however, is that tube amps clip the sound in a softer way than solid-state amps do, and most people seem to prefer tube amp distortion (soft clipping) over solid-state distortion (hard clipping).
When pedals were invented, you could then have the best of both worlds; the overdrive pedal allowed you to have the soft clipping sound of a tube amp without it having to be too loud. It was at this point that, as well as overdrive pedals, distortion pedals and fuzz pedals were invented (distortion and overdrive became two slightly different things). Compared to the overdrive pedal, the distortion pedal had a harsher sound to it with much more grittiness, much like the hard clipping sound of the solid-state amp. The fuzz pedal goes even further; the clipping is so hard that the waveform almost becomes squared, and it heavily saturates the sound as well, giving it a warm, fuzzy quality.
Parameters
Drive/gain: Controls the amount, or harshness, of the distortion.
Tone: Also sometimes labeled as filter, this control, or set of controls, allow you to change the tone. You can change the frequency response of low, mid and high frequencies, or alter the balance between them slightly, sort of like an EQ but more broad.
Vocal effects
Vocoder
The vocoder was originally designed to synthesise speech. It requires to signals, the carrier signal (a synthesised sound usually, like synth strings for example) and a modulator signal (your voice usually).
The modulator signal shapes the sound of the carrier signal. The modulator signal is passed through a filter bank, which analyses the harmonic qualities of the signal, and then, from these analysations, is split into multiple frequency bands. Each of these frequency bands has a bandpass filter applied to it and are tuned to the centre frequency. These filters are applied to the carrier signal, and then the levels of the filters are altered based on the harmonic qualities of the modulator signal.
Parameters
Depth: allows you to control the amount of frequency bands you have, kind of like the resolution of the sound.
Frequency: allows you to set the frequency range.
Talk box
Using a talk box involves amplifying the instrument that you want to make ‘talk’, sending the sound through a tube and using the musicians mouth to change the shape of the sound. The mouth acts like a filter and changes the frequency content.
While vocoders and talk boxes sound pretty similar, the differences lie in how the sound is made. In the talk box, the carrier signal is modulated by the musician themselves, however, the vocoder controls the carrier signal and the modulation signal internally. The talk box is also more popular in rock and soul music, where as the vocoder is more popular in electronic music.
Here is a video of Stevie Wonder playing a talk box.
Lo-fi
Due to the fact that it has emerged relatively recently (early 90s), lo-fi, short for low fidelity, is normally produced with easily accessible, and often cheaply available, digital technology. A large part of the ethos of lo-fi music is to create a feeling of nostalgia, which is achieved by adding analogue sounds and embracing any artefacts that may occur. Sometimes artefacts are added in on purpose. Here is a list of effects that you might add to a sound to make it sound lo-fi.
Bit-crushing: A bit-crusher reduces the resolution of the digital audio. It can distort the sound slightly and create a warmer quality to the sound.
Vinyl crackle: Pretty much what it says on the tin – adds the sound of vinyl crackle over the audio to make it seem as though the music were being played on vinyl.
Telephone EQ: Created by using a narrow bandpass filter around the mid frequencies, this effect it sound as though the audio is coming out of a telephone.
Vocal distortion: Again, pretty self explanatory. Adds distortion to the vocals and can create a more ‘muddy’ sound.
Found sounds: This is the use of recordings of sounds from objects that aren’t necessarily ‘musical.’