Don't know your FM from your LFO? You're going to need RA's tech glossary.
Additive
Algorithm (FM synthesis)
Aliasing
Analog synthesis
Arpeggiator
Attack Time
Auto-mapping
Auto-panning
Band-pass
Bit-crushing
Carrier (FM synthesis)
Cents
Chorus
Compressor
Cutoff Frequency
Decay Time
Delay
Detuning
Digital synthesis
Distortion
Dynamics processing
Effects return
Effects send
Envelope
Equalizer (EQ)
Expander
Filter
Flanger
Frequency Modulation
Gate
GUI
Harmonics
High-pass
Keyboard Tracking
Keymapping
Limiter
LFO
LFO Depth
LFO Rate
Low-pass
MIDI
Modular synthesis
Modulator (FM synthesis)
Monophony
Multiband compression
Multistage Envelope
Notch
Noise Generator
Octaves
Operator (FM synthesis)
Oscillator
Overdrive
Parallel routing
Phase
Phaser
Physical Modeling
Pitch correction
Pitch-shifting
Polyphony
Preset
Release Time
Resonance
Reverb
Ring modulation
Root Key (sampling)
Sample Rate
Sample Resolution
Sampling
Semitones
Self-Oscillation
Series routing
Shannon-Nyquist theorem
Sidechaining
Subtractive synthesis
Sustain Level
Tempo sync (LFO)
Time-based effect
Transposition
Tremolo
Vector
Wah-Wah
Waveform
Wavetable synthesis
Types of synthesis
Additive
Type of synthesis that uses arrays of individual sine waves at varying frequencies and amplitudes. Additive synthesis can be used to create new sonic textures or resynthesize recorded audio for further manipulation and editing.
Analog synthesis
Synthesis based entirely on analog circuitry as opposed to software-based emulations. The first commercially available analog synthesizers were designed by Bob Moog and relied on subtractive synthesis.
Digital synthesis
Based on computer technology, digital synthesizers generate their sounds via software using Digital Signal Processing (DSP) and/or other mathematical algorithms. Early forms of digital synthesis include Frequency Modulation (FM), sampling, wavetable and vector synthesis. Modern software synthesizers (sometimes referred to as soft synths) range from virtual emulations of analog/subtractive to physical modeling.
Frequency Modulation
Originally developed by John Chowning at Stanford in 1967, Frequency Modulation (FM) synthesis relies on arrays of operators (called carriers and modulators) that can be tuned to specific harmonics in order to generate tones. The most famous FM synthesizer is Yamaha's DX-7 (released in 1983), which brought FM synthesis to the masses. Modern software-based FM synthesizers include Ableton's Operator and Native Instruments' FM8.
Modular synthesis
Type of analog synthesizer that consists of separate components (modules) such as oscillators, filters, LFOs, envelopes and more exotic options like ring modulation generators, random voltage generators, and such. Using patch cables, users can configure these modules in any manner, creating extremely complex synthesizer architectures that are otherwise impossible to create.
Physical Modeling
Type of digital synthesis that mathematically models the physical components of an acoustic instrument to recreate its characteristics. Most physical models consist of two parts, the impulse (sometimes called the excitator) and the material. Types of impulse include mallet strikes, blowing, bowing, picking and so on. Materials include metal, pipes, glass, strings, wood, etc. By combining various impulses with materials, "impossible" instruments (like glass violins or 100-meter flutes) can be synthesized.
Sampling
Type of synthesis that uses digitally recorded audio as its basis. Sound is captured as a series of discreet voltages (called samples) via analog-to-digital converters (ADCs). These samples are then stored in digital memory and can be played back, edited, transposed in pitch and/or further manipulated via computer software. From there, the sample data is converted back into audio via digital-to-analog converters (DACs). The first commercially viable sampler was the Fairlight CMI, released in 1979.
Subtractive synthesis
Type of synthesis that uses different types of filters to subtract audio frequencies from oscillators or sampled material. The most basic configuration for a subtractive synthesizer is Oscillator > Filter > Amplifier.
Vector
Originally developed by Dave Smith, inventor of MIDI and the Prophet 5, vector synthesis relies on four oscillators in a two-dimensional plane as its mode of tone generation. The relative volume of each oscillator can be controlled in real-time via a joystick or automated via envelopes and LFOs for timbre-shifting effects. The two most famous vector synthesizers are the Prophet VS and the KorgWavestation.
Wavetable synthesis
First implemented in the PPG Wave 2 synthesizer in 1981, wavetable synthesis is based on digital arrays of closely related waveforms that can be scanned to create dynamic shifts in harmonic and/or frequency content. The term is often used interchangeably to describe any synthesizer technology that contains digital waveform data.
Synthesizer Terminology
Algorithm (FM synthesis)
Different configurations of modulators and carriers are known as "algorithms." On some FM synthesizers, these are user configurable. On others they are preset.
Aliasing
Sonic artifacts resulting from a recording's highest frequency being greater than half of its sampling rate. The modern effect known as "bit-crushing" recreates this sound for musical purposes.
Arpeggiator
Synthesizer feature which automatically steps through a sequence of notes based on an input chord, creating an arpeggio. Often the order and speed in which the notes play can be manipulated.
Attack Time
The initial stage of an envelope. This parameter determines how the note begins.
Auto-mapping
Ability to automatically assign hardware control to software parameters.
Band-pass
Band-pass filters allow a range of frequencies to pass, while attenuating frequencies outside that range.
Carrier (FM synthesis)
The operator that generates the audible tone. The waveform for this tone is modified by the values of the modulator.
Cents
Unit of measurement for tuning. There are one hundred cents in a semitone.
Cutoff Frequency
The frequency at which a filter begins attenuation. In the case of band-bass and notch filters, this parameter governs the center frequency of the filter's range.
Decay Time
Immediately follows the attack stage. The decay stage determines how long it takes for the note's volume to transition to the sustain level.
Detuning
Adjustment of oscillator or sample pitch in very small increments (usually cents) to match the pitch of other instruments or create chorusing effects in multiple oscillator configurations.
Envelope
A series of parameters that control the contour of each note played. That is, how the note begins, sustains and ends. The most common type of envelope is called an ADSR (attack-decay-sustain-release). The most common parameters to be modulated by an envelope are amplifier loudness, filter cutoff frequency and pitch.
Filter
Synthesizer component that subtracts frequencies from the oscillator signal. The four most common types of filter are: low-pass, high-pass, band-pass and notch.
GUI
Graphical User Interface. Interface that allows users to interact with programs though graphical icons and visual indicators.
Harmonics
Series of integer-related sine waves at varying amplitudes that create different timbres. Each waveform generates a specific set of harmonics, giving it a unique character.
High-pass
High-pass filters attenuate frequencies below the cutoff frequency, while passing those above it.
Keyboard Tracking
This parameter allows the filter cutoff to track the pitch of a keyboard for tuned filtering effects.
Keymapping
The process of mapping multiple sampled recordings to different ranges of a keyboard, often for the purpose of recreating a more authentic recreation of a recorded acoustic instrument. Also used for mapping specific drums to different keys.
LFO
Low-frequency oscillator. Used for modulating the value of given synthesizer parameter in a repeating manner.
LFO Depth
Intensity of LFO modulation.
LFO Rate
Frequency of low frequency oscillation; rate of repetition.
Low-pass
The most common type of filter mode. Low-pass filters attenuate frequencies above the cutoff frequency, while passing those below it.
MIDI
Musical Instrument Digital Interface. Industry standard protocol that enables electronic music instruments, computers and other electronic equipment to communicate and synchronize. MIDI does not transmit audio signal—it sends event messages and control signals for parameters.
Modulator (FM synthesis)
The operator that modifies the harmonic and/or frequency content of the carrier.
Monophony
Only one note can be played at any given time.
Multistage Envelope
Some complex envelopes include additional stages beyond the attack, decay, sustain and release.
Noise Generator
Oscillator in a synthesizer that produces a noise signal, typically white or pink.
Notch
Notch filters attenuate a range of frequencies, while passing those frequencies outside that range.
Octaves
Unit of measurement for pitch. Every time the frequency of a waveform doubles, the pitch goes up an octave. A piano's range is seven octaves plus a minor third.
Operator (FM synthesis)
The primary digital component of an FM-based synthesizer. Traditionally, an operator consists of a sine wave generator and a dedicated amplitude envelope. Operator coarse tuning values correlate to the harmonic series.
Oscillator
Analog or digitally based waveform generator that can be tuned to different pitches and used as the starting point for further synthesis.
Phase
Defines a point in time on a waveform's cycle. Often used to indicate the point at which a waveform's cycle begins. The unit of measurement for phase is "degrees."
Polyphony
Multiple notes can be played simultaneously.
Preset
Sometimes referred to as "patch" or "program," a preset is a set of memorized values that are assigned to the various parameters in a synthesizer. For example, one preset may be a collection of settings to recreate the sound of a trumpet, whereas another preset may sound like a guitar.
Release Time
This parameter determines how long it takes for the modulated parameter to return to its nominal value after the key is lifted.
Resonance
Sometimes referred to as emphasis or Q, the resonance parameter creates an amplitude peak centered at the cutoff frequency. Extreme amounts of resonance create a squelching effect, akin to the trademark sound of a Roland TB-303 Bass Line synth.
Root Key (sampling)
The key at which a sample plays back at its original recorded pitch. For most samplers, the initial default root key is middle C.
Sample Rate
The rate at which voltages are sampled, converted into digital information, and stored in memory. The sampling rate determines the frequency range of a given audio recording, based on the Shannon-Nyquist theorem.
Sample Resolution
Also known as "bit depth," the sample resolution determines the range of possible values that can be used to describe the amplitude (loudness) for a given sampled voltage. For example, an 8-bit sample resolution yields 256 loudness values whereas a 16-bit sample resolution yields 65,536 values. Higher resolution results in greater dynamic range in a recording.
Semitones
A chromatic half-step. There are twelve semitones in an octave.
Self-Oscillation
Occurs when the resonance of a voltage controlled filter is set so high as to cause the filter circuitry to generate a sine wave independently of any triggers.
Shannon-Nyquist theorem
States that the highest frequency that can accurately be sampled is one-half of the sampling rate. Thus, to sample a sound that contains frequencies up to 20 kHz, the sampling rate must be a minimum of 40 kHz.
Sustain Level
The sustain parameter determines the level at which the note will be held until the key is lifted.
Tempo sync (LFO)
Synchronizes LFO rate to the tempo of the song. Different note values can be selected for different rhythmic effects.
Transposition
A change in pitch, measured in semitones.
Waveform
A sampled or cyclical (repeating) change in amplitude that reproduces a recorded sound or generates a specific series of harmonics and/or set of frequencies.
Effect terminology
Auto-panning
LFO-modulated motion effect that cyclically moves an audio signal between the left and right speaker channels.
Bit-crushing
Also known as bit reduction, this effect is derived from the distortion and artifacts created by sample aliasing.
Chorus
Thickening effect based on a short, LFO modulated delay. Results range from mild detuning to very synthetic wobbling sounds.
Compressor
Dynamics processor that reduces the volume of a signal when the signal crosses a specified threshold. Often used to add impact and punch to drums and other percussive instrumentation.
Delay
An effect that records audio, holds it in memory for a specified period of time, then replays it. Primarily used for echo, but also serves as the basis for flanging, chorus and rudimentary reverb-like effects.
Distortion
Effect derived when audio exceeds the analog or digital headroom of a signal chain, resulting in clipping. Sometimes referred to as "saturation."
Dynamics processing
Type of effect that modifies the loudness characteristics of an audio signal. Common dynamics effects include compression, gates, expanders and limiters.
Effects return
Audio channel that contains effects that can be utilized by multiple audio channels via effects send routing.
Effects send
Method for sending multiple audio channels to a single effect in varying amounts.
Equalizer (EQ)
Processor used to adjust the volumes of various frequency ranges for creative or corrective purposes.
Expander
A more flexible form of gate, with additional parameters for modifying the intensity of the effect.
Flanger
Effect based on extremely short, LFO modulated delays. Often used for imparting a jet-like sound to sweeps, but can also be used for resonating metallic effects.
Gate
Dynamics processor that works in an inverse manner to compression. When a signal falls below a specified threshold, the gate reduces the loudness, sharply cutting off the volume of a signal. Originally designed for minimizing unwanted background noise in a track, gates are now commonly used for chopped audio effects.
Limiter
An extreme form of compression that can be used to maximize the volume of a track or mixed audio. Used extensively for polishing finished mixes during the mastering stage of production.
Multiband compression
A modern effect that applies two or more compressors to an audio signal. Each compressor governs a different frequency range of the original signal. For example, a user can apply different amounts of compression to the lows, mids and highs, discretely. Often used in the mastering stage of production for improving the overall balance of frequencies in a mix.
Overdrive
A subtler version of distortion, derived from more moderate clipping. Often attributed to the use of vacuum tubes or digital models of various analog signal paths.
Parallel routing
Method for routing effects so that one audio signal feeds multiple discrete effects simultaneously.
Phaser
Using a series of notched filters, phasers create a sweeping effect similar to flangers, but smoother and sometimes more organic sounding.
Pitch correction
Sometimes called pitch-quantizing, this is more modern version of pitch-shifting that also adjusts the formant characteristics of a signal to minimize unwanted tonal artifacts. Thanks to advances in digital processing, pitch correctors can "force" a recorded instrument to stay in key or be transposed to an entirely new key. The most famous examples of pitch correctors are Antares Auto-Tune and CelemonyMelodyne.
Pitch-shifting
Effect that changes the pitch of a signal in real-time by recording the audio digitally, then modifying the data to raise or lower the pitch. Early versions of this effect dramatically altered the tonal characteristics of a signal, creating "chipmunk" effects or "Darth Vader" effects, depending on the direction of the shift.
Reverb
Used for emulating the sound of acoustic ambiences. Most modern reverbs can simulate everything from small rooms to cavernous halls.
Ring modulation
Ring modulators take the input of two signals, then output two additional signals (four total) that are tuned to the sum and difference of the original two pitches. The can result in extremely metallic and/or dissonant effects.
Series routing
Method for routing consecutive effects so that the output of each feeds the next effect in the signal chain. Sometimes referred to as "serial routing."
Sidechaining
Primarily used in dynamics processing, sidechaining allows a second, differing signal to serve as the control source for compression, gating, etc. For example, a bass instrument can be sidechained off a kick drum, so that every time the kick drum hits the bass is lowered in volume. This allows the kick to remain prominent in the mix, despite sharing the same frequency range as the bass.
Time-based effect
Type of effect that relies on one or more delays (or related algorithms) to provide various processing options. Time-based effects include flanging, chorus, echo and reverb.
Tremolo
Similar to auto-panning, this effect creates a single-channel (mono) undulation in signal volume/loudness. Can also be used for gating effects if the processor's LFO allows for square wave or sawtooth options.
Wah-Wah
Based on a sweepabalebandpass filter with an emphasized resonant peak, wah-wah effects are often applied to rhythm guitars for '70s era funk and disco production styles.
