Rhythm & Meter

Hemiola

Pronounced hem-ee-OH-luh

Definition

A hemiola is a rhythmic regrouping in which two bars of triple meter are heard as three groups of two, so the accents shift from 3+3 to 2+2+2. It is especially common just before cadences in Baroque music.

A hemiola makes the meter seem to change for a moment without any change of time signature. In 3/4, two bars normally group as ONE-two-three ONE-two-three. In a hemiola, the same six beats are grouped as ONE-two ONE-two ONE-two, as if one large bar of 3/2 had been laid across the bar line. The listener feels the beat broaden, and then the music settles back into its normal triple meter.

First, a grand staff in 3/4 in G major, five bars. Bar 1: treble quarter notes G4 B4 D5 over a dotted half note G2. Bar 2: E5 D5 C5 over a dotted half note C3. Bar 3: treble half note B4 and quarter note C5 tied into bar 4; bass half note G2 and quarter note C3 tied into bar 4. Bar 4: treble quarter C5 and half note A4; bass quarter C3 and half note D3. Bar 5: dotted half notes G4 and G2. The counts under the treble read 1 2 3, 1 2 3, 1 3, 5, 1. Second, a treble line: a bar of 3/2 with half notes B4 C5 A4 counted 1 2 3, then a bar of 3/4 with a dotted half note G4. — Bars 1 and 2 move in ordinary 3/4, ONE-two-three. In bars 3 and 4 the half notes and the tie across the bar line group the six beats in twos instead: counting six quarter notes across the two bars, the notes start on 1, 3 and 5, and the chords move G, C, D before the cadence on G. The second line shows how those two bars feel: one bar of 3/2 with three half-note beats, then the cadence back in 3/4.

How to spot one

On the page, a hemiola usually shows up as half notes, or notes tied across the bar line, that break the usual three-beat pattern: a half note on beat 1, a note tied over the bar line, and another half note to finish. The harmony and the bass line help too: in a hemiola the chords often change every two beats instead of every three.

Where you hear it

Hemiolas are a hallmark of Baroque music in triple meter. Minuets, courantes and many arias and choruses broaden into a hemiola just before a cadence. Brahms was famously fond of them and used them throughout his music, sometimes over long stretches. The same 3:2 regrouping is part of everyday rhythm in much Latin American music, where 6/8 (two groups of three) and 3/4 (three groups of two) alternate or sound together; "America" from Bernstein's West Side Story is a well-known example of that alternation.

Hemiola, syncopation and polyrhythm

A hemiola is a kind of large-scale syncopation: the accents fall where the meter does not expect them, but here whole beats regroup rather than a single note being displaced.
When the 3+3 and 2+2+2 groupings sound at the same time in different parts, the result is a 3-against-2 polyrhythm, sometimes called a vertical hemiola.

Playing a hemiola

Do not fight it. Let the half notes and ties lean the music into twos, play the bar line lightly, and arrive firmly on the next downbeat. A helpful way to count the two hemiola bars is to count six quarter notes, "1 2 3 4 5 6", with the weight on 1, 3 and 5, then return to "1 2 3" in the following bar.

Common questions

What is the difference between hemiola and syncopation?

Syncopation displaces individual notes or accents off the strong beats. A hemiola regroups whole beats: two bars of three are heard as three groups of two, so for a moment the meter itself seems to change.

What is the difference between hemiola and polyrhythm?

A hemiola usually happens in one part, one grouping after another. When groups of three and two sound at the same time in different parts, it is a polyrhythm, sometimes called a vertical hemiola.