The pitch of a note is determined by its frequency, and frequency can vary within a continuous spectrum. And yet, in the western music tradition, we only use frequencies with discrete values. That’s not a bad thing, but it implies a whole world of possibilities not explored. Microtonal music, also known as xenharmonic music, sets out to make use of the unused frequencies.
I recently tried listening to a lot of microtonal music, because I discovered that you can find lots of it through the microtonal tag on Bandcamp. Sure, a lot of it isn’t very good because anyone can put music on Bandcamp, but there were enough gems that I continued to peruse the tag. I’ll share just two examples. First, I selected Brendan Byrnes, because I think his music has the most pop appeal, while also being unapologetically microtonal.
I showed Brendan Byrnes to a few people, and some of them couldn’t tell that he was making use of microtonal frequencies at all. It seems fairly obvious to me, because I have enough ear training to tell when a note is out of tune (even if I can’t identify the note). But not everyone has that ability. So for my second example, I tried picking something that was so in your face, that it would be hard to miss even if you don’t have any musical training. I present Cryptic Ruse:
These two examples are from the psych-pop and prog-metal genres respectively. In looking for microtonal music, I very quickly learned that you can combine it with any genre. There’s microtonal folk, microtonal classical, microtonal hip hop, microtonal punk, microtonal psychedelic rock, microtonal drone, microtonal black metal, and so on. Of course, the most common genre tends to be electronic, because it’s easy to make electronic sounds of any frequency, while most other instruments would have to be specially customized.
If you’d like to find other examples, I also suggest The Mercury Tree, Sevish, ILEVENS, ZIA, and King Gizzard and the Lizard Wizard.
I don’t want to emphasize the theory of microtonal music too much, because you don’t really need to understand it to enjoy it. Nonetheless, some basic understanding helps us appreciate it more. Also, I like talking about math if you haven’t noticed.
Listening to music is a bit like staring down a cemetery with perfectly aligned gravestones:
Patterns emerge: along certain directions, gravestones seem to line up. The directions where they line up are related to rational numbers, and so it is with music. Certain pitches seem to line up because the ratio between their frequencies is close to a rational number. Technically every number is close to a rational number, but we care most about the rational numbers with small numerators and denominators (e.g. 2/1, 3/2, 4/3, 5/4, 6/5, and 5/3). Typically, the smaller the denominator, the more consonant the pitches sound together, and the higher the denominator, the more dissonant the pitches sound together.
That is a bit of a simplification. There are objective ways to measure consonance and dissonance (see this paper or that one), and it doesn’t just depend on the denominator, but I won’t bore you with the details. Note that “dissonant” is not the same as “bad”, and basically all music relies on some degree of dissonance.
Since our tuning system is based on pitches that are evenly spaced from one another, you might think hitting rational numbers is easy. But in fact, our musical system is based on pitches that are evenly spaced on a log scale. Our system takes an octave (the ratio 2/1), and divides it into 12 equal parts. This tuning system gets very close to the all-important 3/2 ratio, and most people can’t even hear a difference that small. But it’s not quite there.
In microtonal music, there are two common ways to select an alternative tuning system. One way is called “just intonation”–simply select the ratios you want, and play them exactly. This is the method used in the Brendan Byrnes example. The other way is called “equal divisions of the octave” or EDO. The standard tuning system is 12 EDO, but microtonal artists use other tunings like 19 EDO, 22 EDO, 24 EDO, and so on. The Cryptic Ruse example uses 15 EDO.
There are also more exotic systems, and if you’d like to learn more, I recommend 12tone on youtube, who really likes talking about it.
Finding microtonality everywhere
One possible response to all this, is that so-called “microtonal” music is really about westerners rediscovering musical possibilities that have been used in musical traditions everywhere in the world since ancient times. And yes, that’s precisely what it is. No getting around that.
But one of the most interesting things I learned from all this, is that among the world traditions that use microtonality… one of them is the American musical tradition! Specifically, blues has a tradition of “blue notes”, which are in between the pitches used in a standard tuning system. Note that both rock and jazz were derived from blues, and blues derived from African American traditions. Microtonality continues to be used in popular music today, most often by vocalists, although we don’t often talk about it.
So I was thinking back to one of my old favorites, Pyramid Song by Radiohead. I used to wonder what the high note at the 0:31 mark was, whether it was G sharp or G natural. And after my exploration into microtonal music, I came to a quiet realization: it’s neither. I’ve been listening to, and loving microtonality for a long time without realizing it.