What are microtones in music?

18 March 2025, 10:56 | Updated: 19 March 2025, 09:49

What are microtones, and why are they not an everyday part of classical music? We explore the history and mysteries of the ‘notes in between the notes’.

Music is broadly defined as humanly-organised sound, and in that organisation of sound, we need to create some specificity around how we refer to the sounds we organise into our music.

Sounds can be categorised around certain qualities they have, including length, pitch and attack. And they are also categorised into where they fit in the established building blocks of music, including where they fit in certain scales.

Scales are established sequences of notes built from tones and semitones – tones being seen as ‘whole’ intervals between notes, and semitones being ‘half’ intervals between notes. On the piano, each octave is divided into a set pattern of tones and semitones.

Read more: What is a scale in music?

But what about the notes in between these notes? If we hummed a ‘glissando’, or ‘slide’ between these notes, what would those notes be called?

Those are microtones. But what makes them different, and why are they not a standard part of the music we hear on a daily basis?

We explore the mysteries and properties of the notes between the notes, and find out why they’re not an everyday part of classical music.

Read more: What’s the difference between a sharp and a flat note?

What are microtones?

Microtones are pitches in music that sit outside the standard notes of a Western music scale.

They are not found on a standard Western piano keyboard, and should instead be imagined as any of the infinite possibilities of notes you might hear in between any two consecutive piano notes, or notes in standard scales.

They are the notes in between the notes.

The most useful dictionary definition of microtone that we’ve found is in the in The New Grove Dictionary of Music and Musicians, which describes it as “any musical interval or difference of pitch distinctly smaller than a semitone”, going on to give examples of divisions of the octave into more than 12 parts, and musics of ancient Greece and beyond.

Microtonal music is therefore music written to include microtones as well, or instead, of standard tones and semitones.

In the glossary on his Rest Is Noise website, music critic Alex Ross defines microtonal music as “music that uses intervals smaller than the semitone, or uses a tuning system other than the equal-tempered system that has been standard in Western music for the last couple of centuries.”

They have the potential to sound like ‘out of tune’ notes to ears used to Western music, especially when heard alongside the conventional notes of the piano keyboard.

Read more: Useful music theory terms

This piano doesn't have any black keys

What is the difference between a microtone and a quarter tone?

While a microtone refers to any tone imaginable in between the standard notes we use in Western music scales and find on Western keyboards, a quarter tone is more specific and refers to an interval that is half a size smaller than an interval of a semitone.

The notion of quarter tones sitting in between semitone intervals had previously been established by composers like Pierre Boulez, Julián Carrillo and George Enescu from the late 19th century onwards who divided the octave into 24 intervals (finding a pitch between every of the 12 in a standard Western chromatic scale), but MacCarthy needed to take this further to explain the infinite possibilities of all tones and intervals discernible by the human ear.

Where does the term microtone originate?

Confusingly, quarter tone was – and still is at times – used as shorthand to refer to any note smaller than a semitone, but it’s not really specific enough.

The Irish violinist, singer, writer, and authority on Indian music, Maud MacCarthy, was one of the turn-of-the-century thinkers who needed a way to expand music vocabulary to correctly categorise the notes with tiny intervals between them heard in the music she was exposed to. In Indian classical music the word ‘shruti’ defines a microtonal note that sits outside the pitches heard in standard Western music, and in around 1912 MacCarthy landed on using the term ‘microtone’ to translate the concept into English language.

Before that, as early as 1895, Mexican composer Julián Carrillo, had used the more specific terms ‘microtone’ and ‘microtonality’ when referring to music using notes outside the standard 12-note scale.

And other composers have come up with definitions for the notes in between the notes, including the Russian composer Ivan Wyschnegradsky, who used the term ‘ultra-chromatic’ to refer to any intervals smaller than a semitone, and ‘infra-chromatic’ for intervals that are larger than a semitone.

Theorist Marek Žabka liked to use ‘subchromatic’ while American composer Ivor Darreg has opted for ‘xenharmonic’ to refer to his system of scales using notes outside the standard notes of the modern piano.

Read more: What are the keys in music?

How are microtones notated?

Microtones are indicated in music scores using symbols that look similar to standard sharps and flats in notated Western music. Microtones lower than a flattened note often have a flat sign, but flipped backwards, or what looks like a double flat sign, while microtones higher than a sharpened note often have a sharp sign that’s got an extra side (‘double sharp’), or a little cross sign.

Other variations have been devised to communicate the essence of something being ‘like a sharp’ but higher or lower than a standard sharp, or ‘like a flat’ but lower or higher than a standard flat.

Who were the pioneers of microtonal music throughout history?

Pioneers in modern microtonal music include 20th-century American composers Harry Partch and Mildred Couper, who both refused to be confined to the 24 chromatic notes of Western music and instead opted to divide the octave up in 43 pitches and 176 respectively, and they were contemporaries of composers like Charles Ives and Terry Riley in the US, and Béla Bartók, Karlheinz Stockhausen and Pierre Boulez in Europe; all modernists who played with tone and pitches, and experimented beyond the standard notes of Western scales.

But microtonality, finding the notes in between the notes, hasn’t just been the preoccupation of modernist composers closer to our generations.

Renaissance composers wanted to experiment with which pitches they wrote with too. The Italian composer and theorist Nicola Vicentino, writing in the 16th century, worked with microtonal intervals and even built a special keyboard known as the archicembalo with extra keys – 36 in total – to access microtones.

Are there microtones in pop and rock music?

Yes, many artists working today outside classical music, from pop and rock, to Jazz, have experimented with microtones.

Read more: 7 pop songs that deploy microtones ingeniously

Several kings and queens of pop have snuck microtones into their songs, including Dua Lipa, whose ‘Good in Bed’ features microtones in its rickety pianistic hook as well as the chorus. And the iconic opening of Nancy Sinatra’s ‘These Boots Are Made For Walking’ is built from microtonal intervals. Have a listen.

Another big hit, Jet’s ‘Are You Gonna be my Girl’ features microtones, and Australian rockers King Gizzard and the Wizard Lizard are obsessed with microtones, releasing several albums dedicated to them. Try ‘Rattlesnack’ for a good sonic example of these little notes in between.

Other singer-songwriters and icons of popular culture have been known for using microtones, including Paul SImon, Jacob Collier, Aphex Twin, and the experimental Texan rock band Spoon.