Glossary · 64 terms

Music words, defined plainly

The synth, theory and recording words you meet in manuals and videos, each with a one-line answer first and a little more after.

A

Add9 chord Theory: An add9 chord is a major or minor triad plus the ninth: the note a whole step above the root, placed an octave higher. Cadd9 is C E G D, a C major chord with a D added and no 7th.
ADSR Synthesis: ADSR is the four-stage envelope that shapes a synth note over time: Attack (how fast it rises), Decay (how fast it falls to the sustain level), Sustain (the level held while the key is down) and Release (how long it fades after you let go).
Arpeggiator Instruments: An arpeggiator is a synth or keyboard feature that takes the notes of a chord you hold and plays them one at a time in a repeating pattern, such as up, down or random, locked to the tempo.
Arpeggio Theory: An arpeggio is a chord played one note at a time. A C major arpeggio plays C, E and G in turn, often with the C above on top, going up, down or in a repeating pattern.
Autoharp Instruments: An autoharp is a stringed instrument played by pressing a chord bar and strumming. Felt pads under the bar mute every string that is not in that chord, so one strum across all the strings sounds only the chord you picked.
AUv3 Recording: AUv3 (Audio Unit version 3) is Apple's plugin format for iPhone, iPad and Mac. An AUv3 instrument or effect comes inside a regular App Store app and can also load inside a host app, such as GarageBand, as the sound or effect on one track.

B

Blues scale Theory: The blues scale is the minor pentatonic plus one extra note, the flat 5th, for six notes in all. In A it is A C D Eb E G. The added Eb is a blue note, a deliberate rub that gives blues and rock riffs much of their grit.
Borrowed chord Theory: A borrowed chord is a chord taken from the parallel key, the major or minor key with the same home note. In C major, Fm, Ab and Bb are common borrowed chords from C minor, and they give a plain progression a bittersweet or cinematic color.
BPM Recording: BPM (beats per minute) measures tempo: how many beats happen in one minute. At 60 BPM a beat lands every second; at 120 BPM, every half second. A higher number means faster music.

C

Cadence Theory: A cadence is the chord move that ends a musical phrase, the way punctuation ends a sentence. In C major, G to C (V to I) is a full stop, F to C (IV to I) is the softer amen ending, and stopping on G leaves the phrase hanging like a question.
Chord progression Theory: A chord progression is the series of chords a song or section moves through, usually a short pattern that repeats. C, G, Am, F is a progression, written I V vi IV in Roman numerals so it can be played in any key.
Chorus Synthesis: Chorus is an effect that blends a sound with a slightly delayed copy of itself whose delay time slowly wavers. The copy drifts a little in pitch, so one instrument sounds wider and thicker, like a small group.
Circle of fifths Theory: The circle of fifths arranges the 12 major keys like a clock, each a perfect fifth above the one before. C sits at the top with no sharps or flats. Clockwise from C, each key adds a sharp; counterclockwise, each adds a flat, until the two sides meet at F# and Gb.
Click track Recording: A click track is a metronome you hear in headphones while you record or perform: a short tick on every beat at a set tempo, so every take and layer lines up with the same beat. A count-in is the clicks you hear before recording starts, usually one bar.
Cutoff frequency Synthesis: The cutoff frequency is the frequency, in hertz, where a filter starts turning sound down: everything above it on a low-pass filter, everything below it on a high-pass. On a low-pass, a lower cutoff sounds darker and a higher one sounds brighter.

D

DAW Recording: A DAW (digital audio workstation) is software for recording, editing, arranging and mixing music on a computer, tablet or phone. GarageBand, Logic Pro, Ableton Live and FL Studio are all DAWs.
Delay Recording: Delay is an effect that plays back what you just played a moment later, once or many times, so you hear it echo. Time sets the gap between repeats, feedback sets how many repeats you get, and mix sets how loud they are.
Detune Synthesis: Detune sets one oscillator slightly out of tune with another, usually by a few cents (hundredths of a semitone). The two waves drift in and out of step, and the pair sounds thicker and warmer than one oscillator on its own.
Diatonic Theory: Diatonic describes notes and chords that belong to a key's seven-note scale. In C major the diatonic notes are C D E F G A B, and the diatonic chords are C, Dm, Em, F, G, Am and Bdim.
Diminished chord Theory: A diminished chord is a triad built from two stacked minor thirds: a root, a minor third and a flat fifth. Bdim is B D F. It sounds tense and unstable, and it usually leads straight into another chord.
Dorian mode Theory: Dorian is the natural minor scale with its sixth note raised a semitone. A Dorian is A B C D E F# G A, the same as A natural minor with F# in place of F, and that one note makes it sound minor but warmer and less sad.
Drive Synthesis: Drive turns up the signal going into a filter or a distortion stage until the peaks of the waveform flatten, which adds new harmonics. A little makes a synth warmer and thicker, and a lot makes it gritty and distorted.

F

FM synthesis Synthesis: FM synthesis makes sound by letting one oscillator, the modulator, push the pitch of another, the carrier, up and down hundreds or thousands of times a second. The ratio between them picks the overtones and the FM amount sets how bright the tone is.

H

Harmonic minor Theory: Harmonic minor is the natural minor scale with its seventh note raised a semitone. In A, G becomes G#: A B C D E F G# A. That raised note turns the minor v chord into a major V (E in place of Em in A minor), which pulls hard back to the home chord.
High-pass filter Synthesis: A high-pass filter lets the frequencies above its cutoff pass through and turns down the ones below it, so it thins out the low end of a sound. Mixing EQs often call it a low-cut filter.

I

Interval Theory: An interval is the distance in pitch between two notes. Its size is counted in semitones and its name comes from the letter names it spans: C up to E covers C, D and E, so it is a third, and at 4 semitones it is a major third.
Inversion Theory: An inversion is a chord played with a note other than the root at the bottom. C major in root position is C E G; first inversion puts E lowest (E G C) and second inversion puts G lowest (G C E).

K

Key signature Theory: A key signature is the group of sharps or flats written at the start of every line of sheet music, telling you which notes are raised or lowered all the way through. One sharp, F#, means G major or E minor; none means C major or A minor.

L

Latency Recording: Latency is the delay between playing a note and hearing it, such as the gap from tapping a pad to the sound leaving your speaker or headphones. Most players don't notice a delay under about 10 milliseconds, and the longer it gets past that, the harder it is to play in time.
LFO Synthesis: An LFO (low-frequency oscillator) is a slow repeating wave, usually under 20 Hz, that a synth uses to move one of its own settings up and down on a loop: pitch for vibrato, volume for tremolo, or filter cutoff for a wah or wobble.
Looper Recording: A looper is a pedal or app that records a short musical phrase and plays it back over and over, so you can record more parts on top and build a whole arrangement by yourself, one layer at a time.
Low-pass filter Synthesis: A low-pass filter lets the frequencies below a set point, the cutoff, pass through and turns down the ones above it, so it makes a sound darker and more muffled. It is the main filter on most synthesizers.

M

M4A file Recording: An M4A file is an audio-only MPEG-4 file, usually holding sound compressed with AAC. Voice Memos and many other iPhone apps save recordings as .m4a, and most phones and computers play it without extra software.
MIDI Recording: MIDI (Musical Instrument Digital Interface) is the standard language electronic instruments, controllers and apps use to talk to each other. It sends performance messages, such as which note to play, how hard and when to stop, and carries no sound of its own.
Mode Theory: A mode is a scale made by playing the major scale from a different starting note and treating that note as home. On the white keys, D to D is Dorian, E to E Phrygian, F to F Lydian, G to G Mixolydian, A to A Aeolian (natural minor) and B to B Locrian.

N

Ninth chord Theory: A ninth chord is a seventh chord with one more note stacked on top: the ninth, which is the scale's second note an octave up. Cmaj9 is C E G B D, C9 is C E G Bb D and Cm9 is C Eb G Bb D.

O

Omnichord Instruments: The Omnichord is an electronic chord instrument that Suzuki introduced in 1981. You press a button to pick a chord, then brush a touch strip called the strum plate to play that chord's notes like harp strings, often over a built-in rhythm.
Oscillator Synthesis: An oscillator is the part of a synthesizer that makes the raw sound: a wave that repeats at a steady rate. The rate sets the pitch you hear and the shape of the wave sets the basic tone.
Overdub Recording: An overdub is a new part recorded on top of an existing recording while you listen back to it. Record chords, then add a bassline over them, then a melody: each added layer is an overdub.

P

Patch Synthesis: A patch is one complete synth sound: the setting of every knob, switch and slider that makes it, usually saved so you can call it back. Preset and program mean nearly the same thing, and many apps just call it a sound.
Pentatonic scale Theory: A pentatonic scale is any scale with five notes per octave. The usual two are the major pentatonic, a major scale without its 4th and 7th (C D E G A), and the minor pentatonic, the same notes starting on the 6th (A C D E G).
Portamento Synthesis: Portamento is a smooth slide in pitch from one note to the next. On a synth the knob is labeled Glide or Portamento, and it sets how long the slide takes, from a quick scoop of a few milliseconds to a slow swoop of a second or more.
Power chord Theory: A power chord is two notes, a root and the fifth above it, often with the root doubled an octave up. C5 is C and G. With no third it is neither major nor minor, and it stays clear under heavy guitar distortion.
Pulse width modulation Synthesis: Pulse width modulation (PWM) means moving the width of a pulse wave while a note plays, usually with an LFO. As the width changes, overtones fade in and out, and a single oscillator takes on a shimmering, chorus-like sound.

R

Relative minor Theory: The relative minor is the minor key that shares all its notes and its key signature with a major key. It starts on the major scale's 6th note, three semitones below the tonic, so A minor is the relative minor of C major.
Resonance Synthesis: Resonance is a filter control that boosts a narrow band of frequencies right at the cutoff frequency. A little adds bite, and a lot makes the filter whistle and gives sweeps their squelchy, vocal sound.
Reverb Recording: Reverb is the wash of sound that lingers after a note as it reflects off the walls of a room or hall. As an effect, it adds that sense of space to a dry recording or synth, from a small room to a long, cathedral-sized tail.
Rhodes piano Instruments: A Rhodes is an electric piano whose hammers strike thin metal tines, with pickups turning the vibration into a signal for an amplifier. It has a warm, bell-like tone and was a staple of 1970s jazz, pop and soul.
Roman numeral analysis Theory: Roman numeral analysis names each chord by the scale note it is built on. In C major, C is I, Dm is ii, G is V and Bdim is vii°. Uppercase means major, lowercase means minor, and ° means diminished.

S

Semitone Theory: A semitone, or half step, is the smallest step between notes in standard Western tuning: one piano key to the very next key, black or white, or one guitar fret to the next. Two semitones make a whole tone, or whole step, such as C to D.
Seventh chord Theory: A seventh chord is a triad plus a fourth note a seventh above the root. The three you meet most are the major seventh (Cmaj7: C E G B), the dominant seventh (C7: C E G Bb) and the minor seventh (Cm7: C Eb G Bb).
Slash chord Theory: A slash chord is a chord symbol with a bass note after a slash: the chord on the left, the lowest note to play on the right. C/G, read as C over G, is a C major chord with G at the bottom.
Strum plate Instruments: A strum plate is a touch strip on an electronic chord instrument. You pick a chord with one hand and brush the strip with the other to play that chord's notes one after another, like strumming harp strings. The Suzuki Omnichord calls it Sonic Strings.
Subtractive synthesis Synthesis: Subtractive synthesis starts with a wave full of harmonics, such as a sawtooth or square, and shapes it by filtering some of them away, usually with a low-pass filter whose cutoff and envelope set how bright each note is over time.
Suspended chord Theory: A suspended chord replaces the third of a triad with the 2nd or the 4th, so it is neither major nor minor. Csus2 is C D G and Csus4 is C F G, and both sound open and a little unresolved.
Synthesizer Instruments: A synthesizer is an electronic instrument that generates its own sound with circuits or software, then shapes it with controls such as filters and envelopes. Synths come as keyboards, desktop modules, computer plugins and phone apps.

T

Tonic Theory: The tonic is the home note of a key: step 1 of its scale and the note a melody sounds finished on. The chord built on it, the tonic chord, feels like home too. In C major the tonic is C and the tonic chord is C major (C E G).
Triad Theory: A triad is a three-note chord built by stacking two thirds: a root, the note a third above it and the note a fifth above the root. C major (C E G) and A minor (A C E) are triads, and so are most chords beginners learn first.

U

Unison Synthesis: Unison is a synth setting that plays several copies of every note at once, each slightly detuned and often spread across the stereo field. It turns one thin oscillator into a thick, wide sound.

V

Voice leading Theory: Voice leading is how each note of one chord moves to a note of the next. Smooth voice leading holds shared notes in place and moves the others as little as possible, so a progression sounds connected.

W

Waveform Synthesis: A waveform is the shape of a sound wave drawn over time; for a repeating wave, the shape of one cycle. On a synth it is the oscillator's basic shape, usually sine, triangle, sawtooth, square or pulse, and it decides which overtones a note carries and how loud each one is.
Wavetable synthesis Synthesis: Wavetable synthesis plays sound from a stored series of single-cycle waveforms, called a wavetable, and lets you move through that series while a note plays, so the tone morphs from one shape into the next.
White noise Synthesis: White noise is a random signal with the same power at every frequency, heard as a steady hiss with no pitch. Synths use a noise generator for hi-hats, snares, wind, breath and the scratchy attack of plucked sounds.
Wurlitzer electric piano Instruments: A Wurlitzer electric piano makes its sound with hammers striking flat metal reeds, which an electrostatic pickup turns into an electric signal. Its tone is reedy and punchy, and it growls when played hard. The 200 and 200A are the classic models.