The concept here is adapted from Dr. Tom Rhea's "Musical Devices" syllabus via drtomrhea.com. It is an extension of the teaching there; public, and multi-modal for people who learn by reading, listening, seeing, and manipulating.
Musical Devices
Each device below includes a definition accompanied by an interactive example.
Metrical Devices
We'll start with one of the most basic building blocks of music: rhythm.
Hemiola & Duplet
Hemiola refers to the ratio 3:2. While this could refer to other axes of musical variation, in rhythm this tends to mean three beats in the time of two.
Depending on the voice assigned to the hemiola, the effect can be quite different. In the example below, the hemiola is assigned to the bass voice, which makes the topline feel out of time.
Here, the hemiola is assigned to the topline, which makes the bass feel out of time.
Polyrhythm
A polyrhythm layers two rhythms with different subdivisions over the same span of time.
Polymeter & Subdivided Meters
In polymeter, different time signatures run in parallel while sharing the same beat. The bar lengths differ, so the downbeats only realign after the least common multiple of the two meters — for example, four bars of 7/4 lines up with seven bars of 4/4. Unlike polyrhythm, the subdivisions inside each measure do not align.
A 3/4-against-4/4 polymeter realigns every 12 beats.
A 5/4-against-4/4 polymeter realigns every 20 beats.
A 7/4-against-4/4 polymeter realigns every 28 beats.
Odd & Mixed Meters
Mixed meter alternates bars of different lengths — here 4/4 and 3/4 — to create a rolling, asymmetric pulse.
Compound & Simple Meters
Augmentation & Diminution
Augmentation lengthens the durations of a note (or widens its intervals); diminution does the opposite, shortening the durations or narrowing the intervals.
Motivic Devices
Motivic devices act on small musical ideas — phrases, chords, and gestures — by repeating, transforming, or transposing them.
Ostinato
An ostinato is a short motif or phrase that repeats continuously, lending grounding to a piece but sometimes verging on repetativeness.
Ground Bass
A ground bass is an ostinato in the bass: a short repeating bassline supports continuously varying melodic and harmonic material above it.
Canon & Stretto
Free Canon
Canon may or may not adhere to the quality of the leading voice (dux). While a typical a canon written with the quality of C major would be played back with the same intervals and in the same quality, a free canon would be played in a different key that lends a minor quality to the phrase.
Stretto
In stretto, an answering voice enters before the leading voice has finished its statement of the subject. The overlap usually intensifies the music.
Inversion & Mirror Images
Inversion flips a melody around a particular [pivot] pitch. Exact inversion preserves the literal intervals.
Scale-aligned inversion instead mirrors the melody within a key, snapping each pitch to the scale rather than to the original interval.
Retrograde & Reversed Audio
Retrograde plays a musical idea backwards.
Arpeggio & Broken Chord
Block Chords
Block chords are played by sounding all notes of a chord simultaneously.
Broken Chords
Broken chords, by contrast, are a series of chord notes played in sequence, like this common left-hand piano accompaniment.
And like left-hand piano accompaniment, broken chords can serve to keep rhythm while allowing enough space for a melody to be played.
When the pattern becomes more complex, a broken chord starts to verge on melody rather than rhythm.
Pedal Point & Drones
A pedal point is a sustained or repeated pitch held against changing harmony above or below it. Drones serve a similar role with a more continuous, sustained character.
Dominant Pedal Point
In the key of C, pedaling the 5th scale degree (G) and resolving to the 1st scale degree (C) creates tension and release. The highlighted regions mark the pedal tones.
Tonic Pedal Point
A tonic pedal sustains the 1st scale degree while harmony moves above it.
Inverted Pedal Point
Internal Pedal Point
Drones
Drones are similar to pedal points, though may be any note, and tend to be more sustained than the sometimes staccato nature of pedal points.
Modulation
Step Up & Step Down
A whole-step or half-step shift of a phrase or chord progression. Used for modulation between keys, or to create tension and release by moving chromatically through chords that don't fit the prevailing diatonic scale.
Chromatic Tones
Chromatic Passing Tones
Passing Chords
Passing chords are out-of-key chords that give interest to two potentially predictable in-key chords.
Melodic Intervals
Spatial Devices
Spatial devices are about placement: which voice sounds when, where it sits in the stereo field, and how voices interact across time and space.
Hocketing
Hocketing alternates a single melodic line between two or more voices, creating movement and depth in a composition.
The same idea with a bass voice underneath:
Klangfarbenmelodie
Klangfarbenmelodie ("tone-color melody") is closely related to hocketing, but the emphasis falls on alternating timbres and sonic texture rather than on entirely distinct instruments or voices.
Linear Drumming
Like hocketing, linear drumming prevents overlapping voices by only playing one voice at a time, but unlike melodic hocketing which tends to be written from a monophonic melodic idea, linear drumming tends to be useful in reducing complexity in a rhythmic piece.
The same material rewritten so no two voices sound at once:
Echo & Antiphony
Antiphony
Antiphony is a call-and-response style in which two groups (or voices) alternate musical phrases. It's the structural basis of antiphonal psalmody, kirtan, sea shanties, and many work and worship traditions of African and African-American music. See Antiphony for background.
Echo
Correlated & Uncorrelated Pans
Part-writing Motion
Spatialization
Pointillism
Pointillism (also called punctualism or "point music") is a mid-century European compositional style in which each note is treated as a discrete event, individually specified across pitch, duration, dynamics, and articulation. The result is music built from isolated points rather than continuous lines or gestures.