Inspired by Adam Neely’s “7 Levels of Jazz Harmony” and Budjarn Lambeth’s xenharmonic wiki page
You’ve probably heard the term “microtonal music” thrown around — maybe in a YouTube rabbit hole, or from that one friend who won’t stop talking about Harry Partch. Most musicians assume it just means “slightly out of tune” or “weird quarter-tone stuff.” But the rabbit hole goes so much deeper than that.
The truth is, tuning is an iceberg. What we use every day — the 12 notes on a piano, the frets on a guitar — is just the tiny tip visible above the water. Below that surface lies an entire universe of alternative tunings, ranging from “almost identical to what you know” all the way to “music theory must be rebuilt from scratch.”
This article is your guided tour of that iceberg. We’ll go level by level, from the shallowest deviations from standard tuning to the most alien sonic territories imaginable. The levels are adapted from Budjarn Lambeth, a contributor on Xenharmonic Wiki (the internet’s home base for microtonal music theory).
One important note before we dive in: more “xenharmonic” does not mean better. A subtle Level 1 deviation can be just as beautiful and musically rich as a wild Level 13 experiment. This is a map, not a ranking.
A Quick Primer: What Is 12edo?
Before we talk about alternatives, let’s name what we’re departing from. The system used in virtually all Western pop, rock, jazz, classical, and electronic music is called 12edo — twelve equal divisions of the octave. “Equal divisions” means the octave is sliced into twelve perfectly equal steps, each one called a semitone. Every fret on a guitar, every key on a piano — that’s 12edo.
The reason we use it isn’t because it sounds the most beautiful (it doesn’t, actually). It’s because it’s a brilliant practical compromise: you can play in any key, transpose anything, and every instrument can stay in tune with every other instrument. Convenience won over purity centuries ago.
Everything below is measured by how far it departs from this familiar system.
Level 0 — Indistinguishable from 12edo
Examples: 12edo itself, slightly stretched piano octaves, some obscure equal temperaments so close to 12edo that even trained ears can’t tell the difference.
We start at the very surface of the iceberg. Level 0 isn’t really “microtonal” at all — it’s just 12edo, or something so close to it that nobody would ever notice. Technically, a piano with slightly stretched octaves (a common practice in piano tuning) falls here. The stretching is so subtle — less than 4 cents, where 100 cents equals one semitone — that it’s imperceptible to all but the most sensitive ears.
There’s nothing unusual to hear at this level. It’s included just to give us a reference point: the shore of the continent we’re about to leave.
Level 1 — Built on 12edo, But With Small Deliberate Departures
Examples: Pythagorean tuning, Schismic temperament, barbershop singing, classic blues
You’ve already heard Level 1 xenharmony. Every time a barbershop quartet locks into a perfectly resonant chord, they’re drifting slightly away from equal temperament into a zone called just intonation — tuning based on pure mathematical ratios rather than equal divisions.
Just intonation is the tuning system that nature hands you. When you pluck a guitar string, it vibrates not just at its main pitch but also at a series of higher pitches called harmonics — 2x the frequency, 3x, 4x, and so on. Tuning intervals to these natural ratios produces beatless, shimmering chords that equal temperament can only approximate.
Pythagorean tuning, used across much of medieval Europe, is built entirely from stacked perfect fifths. The fifths sound glorious; the thirds are a bit harsh — a trade-off that musicians debated for centuries.
Classic blues music also lives at Level 1. Those expressive blue notes — the slightly flattened thirds and sevenths — are genuinely microtonal in nature, bending toward ratios that 12edo doesn’t have. They feel emotional and “human” precisely because they exist between the cracks of the piano.
If you’ve sung in a choir, played blues guitar, or heard a barbershop group ring a chord until the walls seemed to vibrate — you’ve already experienced Level 1.
Level 2 — Still Familiar, But Audibly Different
Examples: Meantone temperament, 5-limit just intonation, the well temperaments of Bach’s era (Kirnberger, Vallotti, Werckmeister, Young)
Here’s where history gets interesting. For most of the Renaissance and Baroque periods, keyboards were not tuned to our modern equal temperament. They used systems like meantone temperament, which deliberately sacrificed perfect fifths in order to get beautifully pure major thirds.
The result? Keys that sounded different from one another. Playing a piece in C major on a meantone-tuned harpsichord felt warm and stable. Pushing into, say, F# major revealed a harsh, clashing interval called the “wolf fifth.” This wasn’t a bug — it was a feature. Each key had its own character, its own emotional colour.
The well temperaments — developed by figures like Werckmeister and Kirnberger — were a refinement: all keys became usable (solving the wolf problem), but not all keys sounded the same. Many scholars now believe Bach’s Well-Tempered Clavier was written deliberately to exploit these key-to-key differences in character.
This music sounds very familiar to modern ears — it uses the same twelve pitch names — but there’s a warmth, a “bloom” to the consonant chords that 12edo lacks. Level 2 is the taste of history.
Level 3 — Familiar Melodies, Novel Harmonies
Examples: Diminished temperament, Flattone temperament, Ripple temperament
At Level 3, melodies still feel like home — you can still hear familiar scale shapes and phrase patterns — but the harmonies are starting to sound genuinely strange. You might hum along, but the chords underneath will feel odd, spiced, different from anything in your playlist.
Diminished temperament, for example, organizes music around diminished seventh chords rather than major and minor triads. If you’ve ever played a horror movie soundtrack or some jazz that uses the symmetrical diminished scale, you’ve touched on similar sonic territory. This extends that into a whole tuning.
Flattone temperament squashes the fifths even further than meantone did, producing a sound that’s woozy and peculiar — like meantone pushed past its comfort zone.
Level 3 is a good entry point for adventurous composers who want something that listeners can follow melodically, but find surprising harmonically.
Level 4 — Familiar Tunes, Dramatically Different Chords
Examples: Superpyth temperament, Flattertone, Oceanfront temperament
Now the harmonies have flipped completely. You could still sing a scale or a simple melody in a Level 4 tuning and feel oriented. But if someone tried to play a major or minor chord underneath you, it would sound baffling — it’s there, but pulled so far from what your ear expects that it registers as alien.
Superpyth is a good example: it’s built like Pythagorean tuning (stacked fifths), but the fifths are made wider than pure rather than narrower. This produces major thirds that are stretched well beyond 12edo’s already-wide major thirds. The result sounds “futuristic” or “robotic” to some ears — tense, bright, and completely unlike Western pop harmony.
A Level 4 composer can write melodies that a layperson might recognize as “a tune,” but the harmonic world underneath would give that same layperson a headache. In the best possible way.
Level 5 — Lots of New Territory, Familiar Stuff Still Present
Examples: 17edo, 19edo, 22edo, 24edo (quarter tones), expanded temperaments like Meantone[19], Superpyth[17]
This is where we leave the world of 12-note scales and enter systems with more notes — and crucially, more harmonic colour. 24edo, which divides the octave into 24 equal steps, is where you get the quarter tones used in Arabic and Turkish maqam music. Quarter tones are probably the most famous “microtonal” thing most people have heard of.
But 17edo and 19edo are arguably even more interesting for Western musicians. Both preserve recognizable major and minor scales, and retain good approximations of perfect fifths. But each adds new intervals not present in 12edo — different flavours of third, additional chromatic colours.
19edo in particular has an almost meantone-like feel, and has attracted composers who want the full harmonic vocabulary of Western music plus new expressive possibilities. Guitarist Marc Sabat and composer Joel Mandelbaum have both worked in 19edo. You can hear familiar harmonic logic operating, but with extra colours and unexpected twists.
At this level, many of your 12edo melodies and harmonies still work — they’re just not the whole story anymore.
Level 6 — Familiar Shapes Mostly Gone, Mixed Harmonics
Examples: Mohajira temperament, Orwell temperament, Sensi temperament, Harry Partch’s Genesis Scale, full 7-limit and 11-limit just intonation scales
Now we’re really in new territory. The melodic shapes you grew up with are mostly gone. Some of the harmonic intervals will still sound familiar — you might recognize a fifth, or a major third — but many will be completely unfamiliar, pointing at ratios and resonances that standard music theory doesn’t even have words for.
Harry Partch is the most famous composer at this level. His 43-tone Genesis Scale is built entirely from just intonation up to the 11th harmonic — ratios involving the prime numbers 2, 3, 5, 7, and 11. The result is a rich, bizarre harmonic world: chords that shimmer with physical resonance, but bear no resemblance to anything you’d hear on the radio.
Mohajira temperament has a Middle Eastern flavour and centres heavily around neutral thirds — intervals exactly halfway between major and minor thirds, not found in 12edo at all. It’s the sound of a whole different harmonic universe.
Level 6 is where you need to genuinely retrain your ear. You can’t rely on pattern recognition from 12edo. You have to learn to hear new things as beautiful on their own terms.
Level 7 — Still Has Octaves and Fifths, But Forces the Unfamiliar
Examples: Porcupine temperament, Magic temperament, Blackwood temperament, 5edo, 7edo, 10edo, 15edo
Things are getting truly alien. Level 7 tunings still preserve octaves (the 2:1 ratio — the most fundamental consonance in music) and recognizable fifths (3:2), but force you deep into unfamiliar harmonic and melodic territory. There simply aren’t enough familiar intervals available to fall back on.
5edo (five equal divisions of the octave) sounds like something from a gamelan — pentatonic, spacious, and haunting. 7edo sounds like a strange 7-note world where every interval is somewhere “between” its 12edo equivalent. Porcupine temperament breaks the octave into seven roughly equal steps that don’t correspond to any Western scale.
The composer Easley Blackwood wrote etudes in many of these systems, and his Blackwood temperament is designed to highlight those strange, dreamy properties of 10edo. Listening to Level 7 music, you feel vaguely like you recognize the grammar of music — there are phrases, cadences, things that feel like resolutions — but the vocabulary is entirely foreign.
Level 8 — Fifths or Octaves Start to Behave Weirdly
Examples: Mavila temperament, Carlos Beta, Carlos Gamma, 9edo, 16edo, 23edo
Composer Wendy Carlos (famous for Switched-On Bach and the Tron and The Shining soundtracks) designed several alternative equal temperaments specifically to explore what happens when the most sacred cows of Western harmony — the octave and the perfect fifth — stop working reliably.
Carlos Beta divides the octave into steps of about 63.8 cents each, producing 18.8 steps per octave. The fifths are so compressed that they start sounding ambiguous. Carlos Gamma goes further, with steps around 34.2 cents.
Mavila temperament is perhaps the most notorious Level 8 system: it produces a “diatonic” scale, but with the intervals inverted from what you expect. Major and minor are swapped. What sounds like it should resolve, doesn’t. The “right” notes feel wrong, and vice versa.
At Level 8, you often need to use specially designed or electronically altered timbres — inharmonic sounds whose overtones match the unusual tuning rather than clashing with it. The timbre and the tuning have to be co-designed.
Level 9 — No Fifths, Very Weak Octaves, or Both
Examples: Insect temperament, Didacus temperament, no-3s subgroups of just intonation, 8edo, 11edo, 13edo
The perfect fifth — the interval that has anchored virtually all of human harmony for at least 2,500 years — is completely absent at Level 9. Either the tuning system doesn’t produce anything close to a 3:2 ratio, or octaves are so weak and compromised that they barely function.
8edo (eight equal divisions of the octave) is a symmetric system of whole tones — like the whole-tone scale, but stranger. 11edo produces intervals that sit uncomfortably between everything familiar. 13edo sounds like a metallic alien scale, used in the work of experimental composer Cryptic Ruse.
Without fifths to anchor harmony, composers at this level are pushed toward higher prime harmonics — intervals based on 7:4, 11:8, 13:8, and above. This forces genuinely new ways of thinking about consonance and tension. Even inharmonic electronic timbres struggle here.
Level 9 is deep water.
Level 10 — No Octaves At All
Examples: Bohlen-Pierce scale, Carlos Alpha, Canopus temperament, no-2s subgroups of just intonation
This is where the iceberg truly plunges into darkness. At Level 10, the octave itself — the 2:1 ratio, the interval so fundamental that notes an octave apart share the same letter name — is completely gone.
The most famous Level 10 system is the Bohlen-Pierce scale, developed independently in the 1970s by three different people (two of whom were microwave engineers, which feels appropriate). Instead of organizing pitches around octaves, it organizes them around the tritave — a 3:1 ratio, which is an octave plus a perfect fifth. The scale divides the tritave into 13 equal steps.
The result sounds simultaneously logical (it has chords, melodies, even cadences) and utterly, irreducibly alien. Specialized Bohlen-Pierce clarinets have been built to play this music. It’s one of the most radical musical experiments of the 20th century — and it sounds oddly musical once your ear adjusts.
Without octaves, your entire sense of register, transposition, and harmonic equivalence must be rebuilt from nothing. Level 10 forces composers to question the very foundations of what music is.
Level 11 — No Octaves, No Double Octaves, No Twelfths
Examples: Antipyth temperament, Auk temperament, Halftone temperament, 24ed5, 33ed5
At Level 11, we lose not just the octave (2:1) but also the double octave (4:1) and the tritave or twelfth (3:1). These are the three most physically powerful consonances in the harmonic series — the intervals produced by the simplest possible string length ratios. When all three are absent, every last remnant of conventional music theory ceases to apply.
The organizing intervals of these systems are built around the ratio 5:1 (two octaves plus a major third), or other higher-prime ratios. Systems like 24ed5 and 33ed5 divide this interval equally.
Remarkably, there are still consonances at Level 11 — still intervals that sound smooth and resonant, still combinations of notes that work together. The harmonic series runs infinitely; simple ratios don’t stop at 2:1 and 3:1. But finding them, and building a musical language around them, requires starting from first principles.
This is music theory archaeology — sifting through the harmonic series for hidden treasures, with no map inherited from the past.
(Note: Level 12 is deliberately absent — a fun little in-joke for the microtonal community!)
Level 13 — Beyond Harmony Entirely
Examples: 1ed230c, 1ed330c, 1ed370c
And here, at the very bottom of the iceberg, we arrive at a place where the concept of “harmony” — of intervals with simple ratios, of consonance and dissonance based on the harmonic series — no longer applies at all.
Level 13 tunings are not organized around any simple mathematical ratios. Scales like 1ed230c divide an interval (230 cents — slightly less than 2.5 semitones) into a single step, and repeat. The interval is specifically chosen such that when it stacks, there’s no octave, no fifth, no simple relationship to the harmonic series whatsoever.
To make music at this level, everything must be invented from scratch. Instruments, timbres, harmony, melody, rhythm — all of the assumptions built into every instrument, every tuning device, every music theory textbook — are useless. You’re not extending Western music theory. You’re building a completely alien music from the ground up.
Whether that alien music can be beautiful is an open question. The answer is probably yes — but you’d need to spend a long time immersed in the tuning to discover how to speak its language.
So What Does This Mean For You?
Most working musicians will find their most fertile ground somewhere between Level 1 and Level 7. Extended just intonation, 22edo, 31edo, meantone — these are rich territories that are genuinely accessible to anyone with some music theory knowledge and a good ear.
If you want to start exploring, here are some practical entry points:
Listen: Seek out music by artists like Sevish (who works in various EDOs), Wendy Carlos, Harry Partch, and Ben Johnston. YouTube is full of microtonal rabbit holes.
Experiment: Scale Workshop is a free browser-based app that lets you hear any tuning system on a virtual keyboard instantly. No theory knowledge needed — just curiosity.
Read: The Xenharmonic Wiki is the most comprehensive resource on the internet for microtonal theory. It can be dense, but the beginner’s guides are genuinely helpful.
Play: Modern software synths and DAWs (particularly Bitwig Studio and Surge XT) have built-in microtonal support. You can retune your existing plugins with tools like MTS-ESP.
The 12 notes we’ve been handed aren’t the whole of music. They’re just one door. Behind every level described above is another door, opening onto a territory that remains mostly uncharted.
The iceberg goes down a long, long way.
This article was inspired by Budjarn Lambeth’s “13 Levels of Xenharmony” page on the Xenharmonic Wiki, and by Adam Neely’s excellent “7 Levels of Jazz Harmony” video.
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