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The Microtone Zone

I’ve been interested in microtonal music for quite some time, and offer this article to shed a little light on an often misunderstood subject. I’ve played slide guitar for over twenty five years, during which time I have spent a considerable amount of time refining my intonation. Essentially, when playing slide, your guitar is a fretless instrument, as you're not pressing down on the frets to sound a pitch. The slide can be though of as a moveable fret.

In my early years of playing slide guitar, I would play a fretted note, then try to match that pitch with my slide. At some point in this process, it became obvious to me that there were some “in-between” notes that sounded really good, and so I worked on refining those as well. In particular, I noticed that both major and minor thirds sounded much better if I didn’t match try to match these to their closest fretted counterparts. For a long time, I merely described those notes as ones that I could feel in my spine when played right. Furthermore, for many years, when tuning my fretted stringed instruments, I always found that it never sounded quite right to my ears if I simply tuned to an electronic tuner. I’ve always had to temper certain strings differently depending on what key or tuning I was going to play in to get everything resonating with overtones the way I wanted.

Over the years, my spiritual pursuits have often led me to some interesting thoughts and questions. While reading Hazrat Inyat Khans’ Music of Life, he mentions the music of the spheres. This phrase stuck in my mind and I kept wondering what the music of the spheres might sound like. The first time I heard a recording of David Hykes and the Harmonic Choir in the early 1980s, I knew that I had found the answer. A good friend who had taken a workshop with him showed me the basic techniques of overtone singing, and I was hooked.

Whether overtone singing, or simply playing harmonics on a stringed instrument, you will notice if you compare these to fretted notes, or pitches on an equal tempered piano or keyboard synthesizer, that some of the harmonic pitches are not quite the same as the ET ones. On a guitar, play the harmonic on the 9th fret of your low E string. The note will sound as a G#. Try playing a fretted G# or your high E string, you will notice that they aren't the exact same pitch. This gives you an aural introduction into the phenomenon of just intonation. Just intervals such as thirds and sixths are approximately 15 cents off from their equal tempered counterparts, a considerable deviation indeed. Here's a chart showing the intervals in cents of five limit just intonation, plus a couple of seven limit intervals that I find particularly useful in folk music.


interval ratio cents from root note

root 1/1 ------------------------ 0

minor 2nd 16/15 ----------------------111.7

major 2nd 9/8 ------------------------203.9

minor 3rd 6/5 ------------------------315.6

major 3rd 5/4 ------------------------386.3

perfect 4th 4/3 ------------------------498.0

diminished 5th 45/32 -------------------590.2

perfect 5th 3/2 ------------------------702.0

minor 6th 8/5 ------------------------813.7

major 6th 5/3 ------------------------884.4

minor 7th 9/5 -----------------------1017.6

major 7th 15/8------- ---------------1088.3

octave 2/1------------------------1200

Here's a couple of very useful seven limit notes often heard in blues and traditional fiddle styles.

blue minor 3rd 7/6 ----------------------266.9

blue minor 7th 7/4 ----------------------968.8

To make comparisons with equal temperament, just remember that all the 12 ET intervals are 100 cents apart. The subject of temperaments is quite vast, there are plenty of good books available, I suggest reading a few to help gain a better understanding.

My ongoing studies of just intonation have helped to provide me with the language to describe what I want to hear and play. It is of course possible to just "play between the notes" and leave it at that. But to be able to do so with precision adds great depths of subtlety to your music. Many of the folk music styles from around the world that I play use subtle pitch deviations, this really makes an incredible difference. It's debatable whether many traditional folk players are playing or singing exact just intervals at all times, but it's clear that musicians of many styles use microtonal intervals as a powerfully expressive musical tool. Playing folk music in strict 12-ET cleans it up too much for my taste.

I have used various instruments in the past few years to further my explorations of just intonation and microtonality. These have included 19-ET and 31-ET guitars and a fretted 31-ET dulcimer, along with slide guitar, fretless banjo and fiddle. The 31 tone instruments give close approximation to meantone, a much used historical tuning, and also gave near just intervals when I was first learning to play these intervals on a fretless instrument. I've been learning overtone and throat singing, and have a particular interest in playing folk instruments that play in the natural overtone scale such as the Australian didjeridu and the jaw harps and overtone flutes of Scandinavia and eastern Europe. Most recently I've had an acoustic guitar converted to fretless by a luthier friend, and am enjoying improvising on this instrument as well.

© 2002 Seth Austen