Interview: Reilly Smethurst

Australian-born musician and writer Reilly Smethurst recently delivered talks at dBs Music Plymouth and Bristol, delving into his work with microtonal music and its wider applications to modern music. We joined Reilly to discuss how his work in the field has grown over the years, the inspirations along the way and co-inventing a brand new scale. 

Could you tell us a little about how you first got into music, how you’ve progressed over the years and where it has led to you being now?

Family members forced me to attend piano lessons when I was four years old: “The child cannot know what is good. He must be properly initiated.” I am grateful for this! Decades later, musical harmony still strikes me as something profound. I studied music to PhD level, and I’m still not bored by it.

You’re known for your research and application of microtonality. Could you give a brief explanation of what microtonal music is for those who’ve not encountered it?

A microtone is a little note. The common note sizes are tones and semitones. Conventional guitars and pianos can play six equal-sized tones to the octave. A semitone is half a tone; so conventional instruments can play 12 equal-sized semitones to the octave. The most common microtone is a tone divided into four equal-sized quartertones. It is here that problems emerge. Equal semitones are popular; equal quartertones are not.

Reilly Smethurst delivering his talk in the Neve Room at dBs Music PlymouthAt dBs Music, I briefly spoke with staff and students about scales from Northern India and Turkey. These scales allow musicians to play notes that are smaller than a semitone. Smaller than a semitone does not necessarily refer to a semitone cut into two equal quartertones. What if microtones from successful, non-European pieces of music are smaller than equal quartertones? How many pieces of music can you name that use equal quartertones? If you cannot think of many, you are not alone! This is a good starting point.

What happens if one ditches “little notes” and instead uses notes that are larger than a semitone? One of my favourite experimental scales – invented in the 1970s by a German physicist named Heinz Bohlen – uses notes that are roughly 145% the size of a semitone. This appeals to musicians, because scales with lots of “little notes” are difficult to learn and play.

What was it that initially drew you to delve into microtonal music and exploring new scales?

In the twentieth century, many music theorists and experimental musicians dedicated time to equal quartertones and quickly became dissatisfied. See, for example, a brilliant music theorist who passed away in 2016, Ervin M. Wilson. The tremendous amount of work produced by people dissatisfied with equal quartertones amuses me. This is the opposite of Oprah-style, positive inspiration!

Given the historical background, my approach to musical scales is not surprising. As a kid learning piano, I loved music made from equal tones and semitones. Most people do. As a teenager, I noticed that experimental music made from equal quartertones is often neglected or unloved. As an adult, I am not content to echo the success of equal tones and semitones, and I do not wish to repeat the failures of equal quartertones; so I have to find alternatives. It is not easy, but it is also not impossible.

What are some of your favourite examples of musicians fusing together different scales?

I understand the gist of your question, but the word “fusing” is tricky. If you ask kids to play a piece of music in the key of E Major at the same time as a piece in E-flat Major, this counts as “fusing together different scales”; but most kids will complain that the result sounds wrong. Here, purity is preferable to fusion. On this note, I can recommend Michael Harrison’s Revelation: Music in Pure Intonation – a solo piano album based on just one unconventional scale.


Your question can be approached from a different angle. To play a C Major scale, you only need seven notes. Kids call them Do, Re, Mi, Fa, Sol, La, Ti. A conventional piano’s temperament, as I just explained, divides the octave into 12 points. Seven of these points are close enough to the desired notes: Do, Re, Mi, Fa, Sol, La, Ti.

An alternative temperament, which dates back to sixteenth-century Europe, divides the octave into 19 points. Seven of these points are close enough to the desired notes. The same can be said for the 22 Hindustani shrutis or the 24 non-equal quartertones from Turkish conservatories: in each case, seven points from the scale are close enough to the desired notes.

What does this all mean? Some scales or temperaments contain seven-note subsets that are identical or close enough to Do, Re, Mi, Fa, Sol, La, Ti. This is what allows anyone from The Beatles to Paul Simon to make excursions to places like India and South Africa, respectively, without making kids complain that there is a clash or something very wrong with the music. This is what blogs may refer to as a successful “fusion”.

Your question can be approached from yet another angle. In 2012, Brendan Byrnes released an album called Micropangaea. The album features a number of unconventional scales and temperaments, played by custom-fretted guitars and custom-tuned synthesisers. It is thus akin to a catalogue of different scales. Some people from dBs Music might enjoy music from the album; others will think it sounds wrong. Aphex Twin’s Selected Ambient Works: Volume II and Nine Inch Nails’ Ghosts I-IV are two popular albums that use unconventional scales and temperaments.

It became apparent that you’d need custom instruments to put your research into practice, so you commissioned others to modify an electric guitar, bass, mandolin and bowed strings to accommodate the new scale format. Was it a difficult process?

The situation in 2020 is not the same as it was when I began. Today, musicians can use Aaron Spike’s FretFind2D to generate custom fretboard designs. They can then forward the specifications to a luthier that can make guitar necks with unconventional fretboards. If one sticks with Fender-style guitars and basses with “bolt-on” necks, then nothing drastic has to change except the position of each fret on the instrument’s neck. The guitar’s body can remain untouched! It is thus more difficult to make a conventional guitar from scratch than it is to alter the positions of a guitar’s frets.

Smethurst-Promo (1)

Reilly's custom fretted instruments and a decentralised scale diagram by Erv Wilson

For reasons that I will leave aside for now, I had to change my instruments’ open-string frequencies. This process is not uncommon. Conventional guitarists often drop their lowest string down a tone from E to D. If one needs to decrease the frequency of an open-string, then one should buy a higher-gauge string. If one needs to increase the frequency of an open-string, then one should buy a lower-gauge string. Each string’s tension should not deviate too far from the norm.

Synthesisers are even easier to re-tune than guitars. Look for software synths that accept GLY, SCL or TUN files (full list of microtonal software plugins). Some are free; some are expensive. Native Instruments’ Absynth, for example, accepts GLY files; Modartt’s Pianoteq accepts SCL files; Spectrasonics’ Omnisphere and Xfer Records’ Serum accept TUN files.

We should also mention that you co-invented an entirely new scale. Could you tell us a little more about how that came to be?

Reilly SmethurstThat didn’t happen until the final weeks of my PhD period in 2016, so it’s a pointy subject. Erv Wilson – I mentioned him earlier – invented a new type of scale called a Combination Product Set in the mid-1960s. Musicians often interpret a Combination Product Set as a scale with notes that fit within the span of an octave, then the scale can repeat at lower octaves and at higher octaves.

This is normal; but as Kraig Grady and David Keenan pointed out back in 2000-2001, the notes of a Combination Product Set do not have to be reduced to the span of an octave, and they do not have to repeat at the octave. Each note can be interpreted as singular. This theory may appeal to some; but in practice, it is a nightmare.

This particular nightmare fascinated me, so I persevered. I took the idea of a Combination Product Set with “singular” notes, and I came up with a set of 70 notes that do not exceed the range of a grand piano. Why did I do this? MIDI keyboards with 88 keys are not hard to find; and since 70 is a smaller number than 88, each note from my scale can be mapped to a MIDI keyboard. The resultant keyboard design is not easy to play; but it’s beautiful, so why say no?

The work you’ve done on microtonal music seems incredibly daunting to someone without much theoretical knowledge, but your talk quickly sparked ideas amongst both staff and students. How does it feel to see people connecting with your work and applying your techniques to their own work?

I appreciate this! I want to become a grandfather of music. A grandfather – fingers crossed – is less narcissistic than a father, insofar as he is less likely to identify a particular trait in a child and assert, “That’s me!” When I make music, I inevitably think, “That’s mine,” or, “I’m responsible for that,” like a father.

If I were to hear music that is made not by me, but by someone influenced by my work, I might feel partly responsible, but I am very unlikely to think, “That’s mine!” This is the position of the grandfather, and it might be the best possible.

We previously spoke about your desire to compose for film and television. What scores have really resonated with you recently?

'There Will Be Blood'. The score is as great as the title! When the same composer, Jonny Greenwood, scored a recent film called 'You Were Never Really Here', he tweeted #microtones. Listen to the beginning of “Sandy’s Necklace” from the soundtrack: humanity’s potential for ugliness and discord is infinite! We cannot call upon 12 semitones to represent this power forever. The 12 semitones have done an excellent job. They deserve to rest for a while.


I was born around the time of the 1986 Chernobyl nuclear disaster and the 1987 Wall Street crash. When I hear music like Hildur Guðnadóttir’s “Bridge of Death” and “Evacuation” from HBO’s Chernobyl series, I think, “This does not lie.” 

Do you feel there’s something new that microtonal music could bring to the world of scoring?

Yes. If kids are used to “happy” major thirds and “sad” minor thirds, what is in between happiness and sadness? Plenty of microtones! Film/TV directors want this. The problem is, few of them are aware that they want it.

What are your must-have tools for composing and producing your music?

My earlier recommendation is worth repeating. Find out if your computer’s synths accept GLY, SCL or TUN files, and if they don’t, download a free synth that you can re-tune. I first did this in 2011. I programmed a free software synth to play a basic, three-note chord. The notes came from an experimental scale that I had never heard in my life. I realised then, I must have more, as you put it.

What has been the proudest moment for you so far?

I can answer this question when I become a grandfather of music! There’s still time.

What’s next in the pipeline for you?

I just applied for a job in Europe; the Elektronmusikstudion in Stockholm offered me an Artist in Residence position for 2020; I hope to give a talk at IRCAM in Paris later this year; and I want to compose music for a monster in Amsterdam known as the Fokker Organ. The Fokker is an acoustic pipe organ with 31 notes per octave. Unlike most organs, it can be controlled via MIDI, so it doesn’t require a human performer.

One would have to be mad to use all of the Fokker’s available notes, so I am currently fine-tuning a process of rational discrimination. When there are limits in place, I will be free to compose.

What advice would you give to someone eager to turn their passion for music into a career?

“Passion” is an appropriate word! (The etymological meaning is “suffering”, hence the Passion of the Christ.) Most musicians know that the time between paid gigs is difficult, and the time between unpaid gigs is even worse. I’ve only met a few untroubled musicians: they are both experimental and conventional to an extreme. One hand whacks a fruit bowl for a sound-art commission while the other hand functions as a metronome for Primary School students. The point is this: if you can teach music between gigs, the downtime is less lonely.

Where can people learn more about you and listen to your work?

Until I finish my new album, these pieces from 2016 are the best I have to offer. My Wordpress blog has contact details and links to my music theory articles.


Catch up on all our interviews with the amazing guests that have paid a visit to dBs Music and pick up some valuable tips and advice. 

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