© 2025 Juergen A. Riedelsheimer. All rights reserved.

 

Musica non grata: What Happens When We Break the 12-Tone Rule?

 

Have you ever listened to a song you know and loved, only to hear it performed in a way that made it feel beautifully unfamiliar? That might be your brain meeting microtonality - specifically, a tuning system like 31 equal octave divisions (31-EDO). We grow up immersed in 12-tone equal temperament (12-TET), the standard Western system that divides the octave into 12 equal parts. But what happens when we divide it into 31 steps instead? Suddenly, you can explore sonic spaces between the notes - intervals more precise, expressive, and, at first, alien to our ears. But this isn’t just an experiment in sound - it’s an experiment in how the brain adapts to musical unfamiliarity.

 

Why 31-EDO?

31-EDO is not just arbitrary. It provides excellent approximations of just intonation intervals, particularly major thirds and minor sevenths. While 12-TET is a compromised system, 31-EDO gives us richer harmonic color, finer control of dissonance, and access to impossible intervals in the 12-tone world. 31-EDO has roots in the Renaissance theorist Nicola Vicentino, who envisioned expanded tonal palettes long before modern electronic instruments made them possible. In his 1555 treatise, L’antica musica ridotta alla moderna prattica, Vicentino proposed dividing the octave into 31 parts using a specially designed keyboard instrument. Today works like Introduction to Microtonal Music illustrate how modern composers and theorists continue to explore such systems for their theoretical refinement and expressive potential.

 

Listening and the Brain

From a neuroscience perspective, unfamiliar tunings like 31-EDO initially create prediction errors. Our brain is adaptive; however, if we are used to listening to 12-tone music, our brain expects particular familiar chord progression to resolve in a certain, expected way. Likewise, if it doesn’t - at least not in how our brain has been trained it causes dissonance in our expectation patterns. Recent findings suggest that the anterior cingulate cortex (ACC), a brain area involved in error detection and conflict monitoring, plays a role in processing these musical surprises. EEG and fNIRS research show how theta and beta oscillations shift during microtonal listening. Beta oscillations are associated with stability and motor planning through inhibitory control, while theta oscillations reflect conflict detection or the need for cognitive adjustment and control. Together, these offer a window into how the brain negotiates unfamiliar sound worlds.

 

Radiohead in 31-EDO

One striking arrangement is a reinterpretation of Radiohead’s True Love Waits in 31-EDO. In this version, the harmonic shading shifts in nuanced and unexpected ways, deepening the emotional resonance of the piece. What’s especially compelling is the use of uniquely microtonal chords: sub minor 7 chords, sesquiflat chords, half-flat and half-sharp chords, supermajor 7 chords, and neutral chords. These cannot be created in traditional 12-TET and offer a vocabulary for emotion and motion that is not otherwise accessible. Musicians Stephen Weigel and Braelen show that microtonality doesn’t mean abandoning structure or coherence but expanding the palette. Their version integrates microtonal singing, jazz phrasing, and isomorphic keyboards like the Lumatone, showing how 31-EDO can be expressive and intuitive. Depending on their tuning relationships, consonant chords gain new dimensions of richness, sweetness, or tension. Microtonality here is not a gimmick - it’s a deeper lens into musical feeling.

 

 

Compositional Opportunities in 31-EDO

The 31-EDO tuning system makes it possible to modulate to half-sharp or half-flat chords, explore harmonic colors like supermajor and sub-minor intervals, and craft neutral chords that hover between major and minor tonalities. Beyond harmonic innovation, 31-EDO also expands the possibilities for voice leading and modulation in ways that 12-TET simply cannot. These additional tonal steps open up new expressive pathways and transitions that feel organic, surprising, or nuanced. This flexibility makes 31-EDO fertile ground for avant-garde experimentation and film scoring, jazz improvisation, and contemporary songwriting. Microtonal richness supports its harmonic complexity and emotional subtlety and offers composers novel ways to construct narratives through sound.

 

Why Does This Matter

Understanding and embracing microtonality has broader implications. It reflects cognitive flexibility: the brain’s ability to shift frameworks and learn to appreciate what once felt strange. It enhances cultural literacy since many non-Western traditions are built on microtonal systems. It also deepens our understanding of how the brain responds to surprise, ambiguity, and adaptation.

Even without formal training, listeners form tonal expectations in unfamiliar tuning systems through repeated exposure. You don’t need to be a theorist to appreciate 31-EDO music; you only need an open ear and a willingness to let go of what we think music "should" sound like. Let your ears wander. The spaces between the notes are where the music takes place. Hillis refers to how creativity often emerges in the liminal space between structure and chaos: the “space between the notes” where new possibilities unfold (2021).

 

 

References:

 

Bridges, B. (2013). A critical theory and creative practice of microtonal music composition and performance: Vols. 1 & 2 (Doctoral dissertation, University of Western Sydney). University of Western Sydney ResearchDirect. 

 

Mencke, I., Omigie, D., Wald-Fuhrmann, M., & Brattico, E. (2019). Atonal music: Can uncertainty lead to pleasure? Frontiers in Neuroscience, 13, Article 979. 

 

Sabat, M. E., & Tenney, J. (Eds.). (2019). Introduction to microtonal music. Frog Peak Music.

 

Hasegawa, R. (2018). Hearing the tonality in microtonality. Music Theory Online, 24(3). 

 

Hillis, N. (2021). Creativity, chaos theory, and the space between the notes: The artist’s journey. Self-published. https://www.artistsjourney.com

 

EBSCO Fulltext. (2025). The effects of microtonality on listener expectations and preference: A review of neuroaesthetic research.