Audio Effect Types & Their Uses

Distortion effects produce harmonics by removing parts of a signal to create a new waveform. This is either through pushing a circuit past its regular operating level, or judiciously chopping squarish bits out the signal proper. Distortion is no-nonsense vibe with the power to excite any instrument into a cooler, grittier version of itself.

Saturation adds warmth to a signal by producing even-order harmonics. Saturators tend not to dramatically change the character of a sound, making them perfect for use on vocals, drums, and other acoustic instruments. Add saturation to synthesisers, vocals and masters to breath 'life' and 'feeling' into them.

Overdrive produces more extreme even-order harmonics by pushing the signal and having it soft 'clip' the loudest parts. Overdrive was born in 1940s tube amps and it remains a crucial element of any electric guitar effects chain. A little works well on most things: dirtying up synths, 'compressing' vocal shouts, and making snares 'sizzle'.

Distortion is overdrive through the lens of solid-state transistors. It creates 'hard' clipping, which results in odd-order harmonics for considerably more aggressive signal alteration.

Distortion is a rock guitarist's best friend, makes bass lines writhe like demon worms, and generally adds crackle to whatever you put it on.

Fuzz takes the transistor angle runs with it. It mangles a signal into a unique, 'squarish' waveform and then uses a frequency multiplier to add complex harmonic overtones. Fuzz beautifully disintegrates synth patches, 'digitises' percussion into moody samples, and is of course one of the guitar's most iconic effects.

Bit-crushing is a unique distortion effect that lowers the number of volume levels available to express an audio signal. This 'down-sampling' of the bit-rate creates a 'pixellated' sound full of harsh edges and strange artefacts. Bit-crushers are perfect for dark synths and industrial percussion, or for 'chip-tuning' lead guitar.

Boost is simply increasing the volume level of a signal. While not a distortion effect itself, placing a boost in front of a clipping circuit allows you to tailor how much of the signal gets cut off and turned into harmonics. Try placing a boost in front of your tube amp, dirt pedals or fuzz boxes for wild results (just remember to start small).

Stereo effects move sounds left and right in the stereo field through a combination of physical panning between speakers and psycho-acoustic tricks. They add 'width' to a mix when there is asymmetry between the two speakers, or 'phantom mono' when the signals are identical. Use stereo effects to help craft the space your music resides in.

Auto-pan lets you apply automation to the stereo positioning of a signal. It 'crossfades' the percentage split between the left and right speakers over a user-defined time, subdivision of the tempo, or other modulation source. Use it to create rotating soundscapes, a sense of movement, or to draw the listener's focus.

Stereo imaging widens (or narrows) a signal through panning as above, but also through the use of psycho-acoustics. By doubling a mono signal, placing it left & right, and subtly delaying one side, stereo imagers create 'phase cancellation'. This tricks our brain into thinking the sound comes from beyond the 90-degree width of the speakers.

Parallel imaging is actually a technique that mimics the effects of a stereo imager. By following the above steps in your DAW, you can achieve similar results without having to load up another plugin. The power of parallel imaging is that you can process each side of the image separately, and exert greater control over the subsequent soundscape.

Mono summing is a simple utility effect that takes a stereo signal and converts it to mono. This is invaluable for preventing unwanted phase cancellation on crucial elements of a mix. Use mono summing on stereo samples, especially kick and bass, or on the master to check for unwanted noise, phasing, or other 'frequency-crowding' problems.

Time-based effects copy a signal and delay the onset of the subsequent signal to create variations on the echoes which naturally occur in nature. They can range from perfect digital replications to muddy after-effects with little relation to the source material. Time-based effects add 'depth' to a signal and are thus crucial mixing tools.

Room reverb takes a physical (or algorithmic) room with desirable sonic characteristics and projects a signal into it. A microphone then captures the resultant sound as it bounces around the angles and surfaces. Room reverb is great for giving a signal a sense of space that it may not otherwise possess.

Plate reverb trades a room for a literal (or virtual) sheet of steel held aloft by tense springs. A special transducer projects the signal onto the metal plate and another picks it up again. The unnatural sound of plate reverbs is perfect for blending with room reverb, creating bright 'slapbacks', or building alien soundscapes.

Spring reverb uses the same principle but with a tense spring strung inside a sealed 'tank' (or an emulation thereof). They tend to have a dark, 'bouncy' tone with a lot of low end. Use spring reverb on moody (especially surf) guitars, layer it on room recordings for extra vibe, or smash it with noise to create shuddering thunderstorms.

Convolution reverb takes the vast power of modern Digital Signal Processors (DSPs) uses it to create Matrix-esque simulations of physical (or imaginary) spaces. These possess far more detail than algorithmic room reverbs though may not be as 'musically-tuned'.

Convolution reverbs are perfect for SFX, dark electronic music, and 'live' emulations.

Digital delay records a signal and plays it back for a defined number of repeats at defined volume levels. The 'perfect' nature of these repeats gives them an unnatural quality that can turn a mundane signal into a new instrument. Experiment with digital delay on mid-/high-register electronic sounds, clean guitars, or abstract vocals.

Echo seeks to better mimic the dark, degraded repeats found in nature through the use of analogue tape machines or bucket brigade devices. Their analogue (or emulated) nature creates imperfect repeats heavy on 'colour'. Apply echo to lead lines to add space around an instrument while keeping the original signal in the foreground.

Ping-pong delay is a type of stereo delay that uses an LFO to pan the delayed signal left and right at defined intervals. This creates width whilst also drawing the listener's attention to the 'moving' signal. Ping-pong delay adds rhythm to percussion, fractures vocals, and turns pads into a seething sonic confluence.

Asynchronous delay is another stereo delay that places its repeats to the left and right. The difference is that the left and right signals have separate parameter controls so they sound like two unique delays. Use asynchronous delay to disorientate listeners as instruments get locked in evolving patterns of call and response.

Frequency Modulation effects increase and/or decrease the pitch of a signal over a specified period of time. This is achieved through applying an LFO to the pitch of the original signal or a delayed double. Frequency Modulation effects change the timbre and 'vibe' of a signal without drastically altering its emphasis or timing.

Chorus mixes a signal with a slightly-delayed second signal, to which an LFO modulating the pitch has been applied. This creates a 'shimmering' effect as subtle phase cancellation occurs between the two signals. Add chorus to long notes for a dreamy quality, to short notes for vibe, or to vocal takes for extra strength and body.

Vibrato also uses an LFO to modulate pitch, but only of the original signal. It produces a 'warbling' effect which can become quite choppy as the rate of the LFO is increased. Apply subtle vibrato to voices and instruments to emulate acoustic vibrato techniques or warped records, or crank the depth to create underwater ray guns.

Pitch Shifting (AKA pitch transposition) is a broad term under which effects like vibrato fall. It's included here to represent the extreme pitch effects available to synthesists who apply modulation directly to the frequency of their oscillators. Use pitch shifting for dizzying soundscapes, evolving timbres, and emergent melodies.

FM Synthesis modulates the frequency of an audible signal (the carrier) by an inaudible one (the modulator). It is useful for creating timbres that are difficult to achieve with other forms of synthesis. Explore FM for bell-like percussion, glassy electric pianos, and cutting kick and bass that's one knob turn from atonal madness.