An introduction to the Xenharmonic Alliance Monthly Tunings group — and why they might change how you hear music
If you’ve spent any time studying music theory, you know that the twelve notes of the piano keyboard feel inevitable. They’re baked into how we talk about chords, scales, keys, and harmony. But here’s something most music theory classes don’t mention: the choice to divide the octave into twelve equal steps is just that — a choice. And a surprisingly large community of composers has decided not to make it.
The XA Monthly Tunings group on Facebook is one of the most active corners of that community. Every month, its roughly 475 members vote on an alternative tuning system, then spend the next four weeks composing, improvising, theorising, and sharing whatever they discover in it. The results range from haunting baroque-style fugues to wild electronic improvisation — all in tuning systems that most musicians have never heard of.
What is the Xenharmonic Alliance?
The Xenharmonic Alliance (XA) is a social group for musicians interested in “xenharmonic” music — meaning music that uses tuning systems other than 12-tone equal temperament (12edo, the standard tuning of the modern piano). The Alliance was originally founded around 1958 in Los Angeles by Ivor Darreg and Glen Prior, and has grown into a worldwide community spread across Facebook groups, a Discord server, and a collaboratively edited wiki called the Xenharmonic Wiki.
The Monthly Tunings group is a focused offshoot of the main XA Facebook group. It was founded by Antoine Beaudet, who still administrates it alongside Claudi Meneghin. Each month, Meneghin posts a poll, members nominate and vote on a tuning system, and everyone dives in together.
What do they actually mean by “a tuning”?
This is where it helps to know a little theory. In standard Western music, we use 12-tone equal temperament: the octave is divided into 12 equally spaced semitones, and every key sounds the same (just transposed). This system is a compromise — it makes every key playable, but slightly mistuned relative to the pure acoustic intervals (perfect fifths, major thirds, etc.) found in nature.
Microtonalists explore what happens when you use a different number of equal divisions, or a completely different underlying logic. The group’s past tuning choices give you a sense of the range:
- 19edo — 19 equal divisions of the octave. Major thirds are strikingly pure; minor thirds are very close to their just intonation equivalents. Chord progressions feel similar to 12edo but with a sweeter, slightly melancholy colour.
- 22edo — 22 equal divisions. Fifths are slightly sharp. The system supports a variety of temperaments not available in 12edo, and major thirds come out notably sharp, giving harmonies a brighter, almost tense quality.
- 31edo — Often considered the friendliest entry point for classical musicians, since its diatonic scale works just like meantone and its major thirds are exceptionally pure.
- Porcupine temperament — not an equal division at all, but a “regular temperament” with its own internal logic (more on this below).
The group doesn’t just pick equal divisions of the octave, either. They’ve explored just intonation subgroups, historical temperaments, tunings generated by the Fibonacci sequence, and even something called Bohlen-Pierce, which divides a perfect twelfth (rather than an octave) into equal steps.
March 2026: Porcupine Temperament
At the time of writing, the group is working through Porcupine temperament — and it’s a good example to dig into, because it illustrates how different the logic of these systems can be from anything in standard theory.
In standard meantone (the theoretical basis of 12edo), intervals chain together via stacked fifths. The circle of fifths is foundational: C–G–D–A–E–B–F#… and eventually back to C. Porcupine works on a completely different principle.
Porcupine temperament is generated by a slightly flat minor whole tone — about 160 to 165 cents (recall that a regular whole tone is 200 cents, and a semitone is 100 cents). Two of these generators stacked together represent a minor third (6/5), and three of them represent a perfect fourth (4/3). This means the perfect fourth is divided into three equal steps — a feature called an “equal tetrachord” that is characteristic of porcupine’s scales. Xenharmonic Wiki
Why does this matter musically? Because the system of chords and progressions that emerges is genuinely different from anything in common practice harmony. The defining comma that porcupine tempers out is 250/243 (sometimes called the “porcupine comma”). Xenharmonic Wiki In practical terms, this means three stacked minor thirds land on a perfect fourth — a relationship that doesn’t exist in 12edo at all. Chord progressions in porcupine feel like they’re following a different gravitational logic; familiar-sounding triads appear, but they connect to each other in unexpected ways.
In this month’s group activity, members have already been exploring that strangeness. Claudi Meneghin composed a short baroque-style fugue for oboe, clarinet, and bassoon in a porcupine well temperament (a tuning where the porcupine generator varies slightly across the scale, in the tradition of Bach-era well temperaments). Juhani Nuorvala shared a composition exploring the characteristic “three minor thirds equal two perfect fourths” bass line — what you might call the porcupine equivalent of a lament bass. Member Budjarn Lambeth posted a piece in porcupine[15], using 59edo as the underlying equal temperament.
The most common equal temperaments used to realise porcupine are 15edo, 22edo, and 37edo (which is 15 + 22 — these three EDOs are closely related through their shared support of porcupine).
A glance back: ten years of strange tunings
Looking at the group’s archive is like reading a history of xenharmonic exploration. A few highlights from the decade-plus of monthly tunings:
2016 saw the group work through Pajara temperament, Sensi, and Porcupine (which returns this March, nearly ten years later). Meneghin wrote fugues in nearly every tuning — a tradition he’s continued ever since.
2017 included Bohlen-Pierce in January (the scale that abandons the octave as its period of repetition), followed by Mavila, a temperament where the diatonic scale sounds like a “funhouse mirror” version of major/minor — because its generator, a slightly flat fifth, causes the large and small steps of the scale to swap roles compared to meantone.
2018 and 2019 explored a number of unusual systems: Monarda (a 12-note subset of a 17-limit rank-3 temperament), Polaris (a 17-note JI constant structure), and a tuning called 13.888edo — a non-integer EDO.
2020 included “Tunings using phi” (the golden ratio) and Miracle temperament, which has an unusually efficient generator that approximates a large number of just intervals with very few steps.
2024 featured Eagle 53, a temperament based on 53edo with an eagle-themed name; Orwell temperament; and a month of 34edo, in which someone arranged the Atlantis theme from the video game Banjo-Tooie.
2025 was particularly productive. Highlights included 55edo (historically used by some baroque composers as a theoretical basis for meantone), Peppermint-24 (a tuning with both sharp and flat versions of every interval), 70edo, 80edo, and 27edo. Meneghin arranged Chopin, Joplin, and Gesualdo into these systems; Budjarn Lambeth improvised in nearly all of them; and Herman Miller contributed compositions throughout the year.
Who are the main composers?
A handful of names appear across almost every month in the archive.
Claudi Meneghin is the group’s co-administrator and most prolific composer. He has a weakness for baroque forms — fugues, chaconnes, canons — and consistently applies them to whatever tuning the group has chosen, often with technically demanding results. His arrangements of existing repertoire (Bach, Chopin, Gesualdo, Joplin) into microtonal tunings are a recurring feature.
Herman Miller is a veteran of the xenharmonic community whose compositions appear in almost every year. His catalogue spans a wide range of styles, from ambient to structured counterpoint, and he has also contributed technical resources like Lumatone keyboard mappings for specific EDOs.
Budjarn Lambeth is a prolific improviser and wiki contributor who has been extremely active in the group since at least 2024, contributing improvisations each month — often multiple pieces per tuning, exploring different scales within the chosen system. Lambeth also regularly posts theoretical observations alongside the musical contributions.
Juhani Nuorvala is a Finnish composer who has appeared in the group during the current porcupine month, with a piece exploring porcupine in 22edo.
Hans Straub is an active theorist who contributes to the German Xenharmonic Wiki and recently assembled an entire album called Nights in Sixteen for January 2026’s 16edo month.
What equipment do they use?
One of the group’s stated interests is sharing tools and techniques, not just compositions. Members use a wide range of setups:
Software synthesisers (soft synths) are the most common approach — tools like Surge XT, ZynAddSubFX, and various VST instruments can be retuned using Scala (.scl) or TUN files. DAWs like Reaper handle microtonal MIDI more flexibly than most others.
Some members use the Lumatone keyboard, a large isomorphic keyboard whose hexagonal layout makes many microtonal scales more physically playable than a standard piano keyboard.
Others use custom physical instruments, retuned guitars, or software like Leimma and Scale Workshop to design and audition scales.
Why would this interest a “normal” musician?
If you’ve spent time learning conventional music theory, a lot of what makes microtonal music interesting is exactly the things that theory has made familiar. Chord progressions, voice leading, tension and resolution, modal colour — all of these concepts still apply in microtonal systems, but they behave differently. The fifth might be slightly sharp. The third might be in a different relationship to the root. The “leading tone” might not exist in the way you expect.
Working in a different tuning is a bit like learning to walk on a slightly different gravitational field: your instincts are still useful, but you have to rebuild your intuitions from scratch. Composers in the XA Monthly Tunings group are doing exactly that, every month, in a collaborative setting where everyone is exploring the same new territory at the same time.
The Xenharmonic Wiki is the best starting point for deeper reading: https://en.xen.wiki. And if you want to listen before you read, searching any of the tuning names above on YouTube will turn up a surprising amount of music.
The XA Monthly Tunings group is a private Facebook group. The main Xenharmonic Alliance group (XA II) is public and a good place to start if you want to join the community.
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