Western equal temperament divides the octave into 12 equal half steps. Most of the world's music does not. Learning to hear microtones, quarter tones, and alternative tuning systems expands the ear's range and challenges its deepest assumptions.
EQUAL TEMPERAMENT AS ONE CHOICE AMONG MANY
The Western 12-tone equal temperament system — in which the octave is divided into 12 equal semitones, each 100 cents wide — is a compromise tuning adopted gradually in Europe from the 17th to 19th centuries. It enables instruments to play in all 24 major and minor keys without retuning, at the cost of slightly mistuning every interval except the octave. A pure (just intonation) perfect fifth spans 702 cents; an equal-tempered fifth spans 700 cents. The difference is small but audible to trained ears, particularly in sustained chords.
The adoption of equal temperament as the Western standard does not mean it is universal. Most musical traditions outside Western Europe use different pitch systems, many of which divide the octave into more than 12 pitches or use intervals that fall between the piano's keys. The Arabic maqam system, the Turkish makam system, Iranian radif, Indian classical music (both Hindustani and Carnatic), and many African and Southeast Asian traditions all use microtones — intervals smaller than the Western half step.
MICROTONES AND QUARTER TONES
A quarter tone is half of a Western semitone — 50 cents. Many Middle Eastern and Central Asian music systems use quarter tones as standard intervals. In the Turkish makam tradition, the octave is theoretically divided into 53 equal parts (each called a comma, approximately 22.6 cents), allowing for intervals of 1, 2, 3, 4, 5, and 9 commas. In practice, the most common intervals are 9 commas (tanini, a whole tone), 8 commas (büyük mücenneb), 5 commas (küçük mücenneb) and 4 commas (bakiye). These distinctions produce the characteristic sound of maqam-based music — slightly different from anything in the Western equal-tempered system.
For Western-trained ears, microtones initially sound "out of tune." This is a learned perception, not an inherent acoustic reality. The intervals are not wrong; they are simply unfamiliar. With exposure and study, the ear gradually adjusts and begins to perceive the expressive nuances of microtonal systems: the way a slightly lowered note creates an emotional colour impossible in equal temperament, or the way a raised note creates a brightness beyond the Western scale.
HINDUSTANI AND CARNATIC INTONATION
In North Indian classical music (Hindustani) and South Indian classical music (Carnatic), the precise intonation of each note in a raga depends on its function within that raga — the same pitch class may be slightly higher or lower depending on whether it is ascending or descending, or depending on its melodic context. The phrase 'komal Re' (flat Re) in a given raga may be intonated slightly differently from 'komal Re' in another raga. This contextual intonation is fundamental to the expressive character of raga music and is transmitted entirely aurally — there is no notation system that captures these microintonational nuances.
SELF-DIRECTED LISTENING EXERCISES FOR MICROTONAL AWARENESS
Listen to Turkish classical music (Ottoman classical music) and focus on melodies: identify moments where a note seems to sit between the piano's keys. Do not try to label it; simply accept that it is a valid pitch. Repeat this with Persian classical music (dastgah music) and with recordings of Carnatic voice (such as M.S. Subbulakshmi or D.K. Pattammal). Over time, the ear begins to hear these intervals not as out-of-tune approximations but as precise, expressive pitch choices.
JUST INTONATION AND PYTHAGOREAN TUNING
Before equal temperament, Western music used various non-equal tuning systems. Pythagorean tuning (attributed to Pythagoras, ca. 500 BCE) uses pure perfect fifths (frequency ratio 3:2) to generate all other intervals. The resulting major third is wider than the just-intonation major third (5:4) and sounds noticeably brighter and more strained. Pythagorean tuning was dominant in medieval European music and produces a distinctive sound for medieval polyphony performed on period instruments.
Just intonation uses small-integer frequency ratios for all intervals: octave 2:1, fifth 3:2, fourth 4:3, major third 5:4, minor third 6:5, major sixth 5:3, and so on. Just intonation produces the purest possible consonant intervals but has a fundamental problem: not all keys are equally usable. A keyboard tuned in just intonation in C major will sound out of tune in any other key. This problem is what motivated the gradual development of temperament systems leading to equal temperament.
WELL TEMPERAMENT
The "well-tempered" tuning that Bach championed in his Well-Tempered Clavier (1722, 1742) was not equal temperament but one of several unequal but usable systems that allowed playing in all 24 keys with acceptable intonation. Each key sounded slightly different — some keys were brighter, some darker — and Bach exploited these differences for expressive effect. The preludes and fugues of each key in the WTC have distinct moods partly because the tuning gives each key a unique character.
This key-character tradition was lost with the adoption of equal temperament, where all keys sound identical except for their absolute pitch height. Some early-music performers today still use well-tempered tunings for performing Bach and other Baroque keyboard music.
CENTS NOTATION
Cents are a logarithmic unit for measuring musical intervals: 100 cents = one equal-tempered semitone; 1200 cents = one octave. Cents notation allows precise specification of pitch differences smaller than a semitone. A pure perfect fifth is 702 cents; an equal-tempered fifth is 700 cents — a 2-cent difference. A pure major third is 386 cents; an equal-tempered major third is 400 cents — a 14-cent difference. The latter is the largest tuning compromise in equal temperament and is the reason equal-tempered chords sometimes sound slightly "brittle" to ears sensitive to pure intonation.
MICROTONAL COMPOSERS IN THE WEST
Several 20th-century Western composers explicitly composed for microtonal tunings. Harry Partch (1901-1974) developed a 43-tone-per-octave just intonation system and built custom instruments to perform his music. La Monte Young (b. 1935) has composed pieces using extreme just intonation ratios. Ben Johnston (1926-2019) wrote string quartets requiring extended just intonation. Wendy Carlos's electronic music explored alpha and beta scales — equal divisions of the perfect fifth rather than the octave.
Microtonal music challenges Western listeners precisely because it requires accepting pitch relationships outside the familiar 12-tone system. Patient listening, often with repeated hearings, gradually reveals the internal logic of these tuning systems.
INDIAN CLASSICAL VOCAL TECHNIQUE
North Indian (Hindustani) and South Indian (Carnatic) classical vocal traditions develop pitch precision to extraordinary levels. Singers spend years training the ear and voice to produce specific intonations of each scale degree within each raga. The ornaments (gamaka in Carnatic, meend in Hindustani) involve precise microtonal sliding, bending, and shaking of pitch — techniques that have no analogue in Western classical singing.
For ear training, listening to recordings of Hindustani and Carnatic singers reveals what is humanly possible in pitch control. Subbulakshmi's recordings of the kriti repertoire, Pandit Bhimsen Joshi's recordings of khyal, and the recordings of Kishori Amonkar all demonstrate microtonal precision that astonishes Western-trained ears.
GAMELAN AND OTHER NON-WESTERN TUNINGS
Indonesian gamelan ensembles use specific tunings unique to each instrument set. The two main gamelan scales — slendro (a 5-tone approximately equal division of the octave) and pelog (a 7-tone unequal scale) — are neither just intonation nor equal temperament. Each gamelan ensemble is tuned slightly differently from every other, with the specific tuning being part of the instrument set's identity.
Thai classical music uses a 7-tone equal-tempered scale (each interval 171 cents, slightly different from Western intervals). Persian classical music uses quarter-tone-like intervals in specific dastgah (modal frameworks). Each tradition's tuning system reflects its own aesthetic and theoretical principles.
LEARNING TO HEAR ACROSS CULTURES
The transition from Western equal-tempered hearing to multi-cultural pitch awareness is gradual but profound. Initially, non-Western intonation may sound "off." With sustained listening (months to years), the ear adapts: the perception of "in tune" expands to include the precise intonations of each tradition. This expanded ear is not a loss of Western pitch precision but an addition of new perceptual capacities.
For structured study, university ethnomusicology programmes provide the most rigorous frameworks. For self-directed study, the Smithsonian Folkways Recordings catalog contains thousands of field recordings from world music traditions, providing source material for systematic exploration of global pitch systems.
SOURCES & FURTHER READING
Signell, Karl. Makam: Modal Practice in Turkish Art Music. Asian Music Publications, 1977. Nettl, Bruno. The Study of Ethnomusicology. University of Illinois Press. Chapter on tuning systems. Strutt, John William (Lord Rayleigh). Theory of Sound. Dover reprint. — Acoustic foundations of tuning and intervals. Parncutt, Richard. Harmony: A Psychoacoustical Approach. Springer, 1989.