Glossary of Music Tuning Definitions

A musical tuning dictionary for ethnomusicologists, early music buffs, xenharmonicists, and others.

acompositia bearing plan cents comma gamut hertz (hz) intentional microtonality linear scale microtonal modulation moment of symmetry (MOS) oven pleng ratio recipe rational intonation repeat ratio scale scale_fetishism tonality tuning tuning psychosis xenharmonic xentonality

Acompositia

Similar to the asphyxia suffered by mountain climbers, acompositia is an illness that can afflict those who spend their lives exploring the frontier of sound. Symptoms are a feeling of peace, warmth and bliss, and a desire to never return from the mountain. Victims of acompositia never write back a postcard to their friends or family in the form of a new composition, essentially disappearing into the wilderness, their compositional potential vanishing like a lost martian space probe that just stops transmitting and no one knows what happened.

Bearing Plan

A bearing plan is a set of directions for tuning an instrument by ear.

Cents

A cent is a unit of relative pitch measurement. When you play two notes together, you can explain the difference in pitch between them by taking the ratio of their frequencies which is an exponential measurement, or you can take the logarithm of the ratio of their frequencies which is a linear measurement. The most common way to do linear measurements of pitch is to use cents. There are exactly 1200 cents per octave of 2/1. There are exactly 100 cents per equal tempered semitone. A pythagorean fifth (frequency ratio of 3/2) is 701.9550009 cents.

Comma

If you have two intervals that are close to one another such to the extent that you might try to make one pass for the other, or want them to be equivalent under some use, the difference between the two intervals is called a comma.

For example, the difference between a stack of twelve fifths of 3/2 and a stack of seven octaves of 2/1 is (3:2)12 / (2:1)7, which is 531441:524288, or 23.46 cents, roughly an eighth of a whole tone. Much ado is made about the fact that these two intervals don’t match in a theoretical tuning of pure fifths called Pythagorean Tuning, and the western standard of twelve tone equal temperament is said to be the solution to this conflict.

This conundrum, considered an unsolvable puzzle that has lasted centuries because of unchangeable facts of unyielding mathematics, is nothing more than a case of small-minded thinking inside of a box of one’s own choosing. First, there are an infinite number of useful and marvelous tunings that don’t even need such constraints. Second, if you really must have all pure fifths in a conventional sounding tuning, it is a trivial matter to use the seventh root of 3:2 as your basic chromatic step instead of the 12th root of 2:1. This yields a slightly stretched octave of (3:2)12/7 or 1203.35 cents, which is not just only slightly and unnoticeably sharp of the 2/1 octave at 1200.0 cents, but it is basically the same octave that is used to tune all modern pianos anyway. Desiccate the comma by tempering the octave instead of the fifth and you have a great and useful tuning that you are already familiar with.

Gamut

The complete set of notes that can be played on an instrument is the instrument’s gamut. For example, the gamut of a modern pianoforte consists of 88 notes, from A0 to C8. Gamut is a synonym for range. The popular expression to run the gamut means to span the complete range of possibilities.

Hertz (hz)

Hertz is a unit of measurement of frequency it means cycles per second. When a conductor says that concert pitch is A-440, he means that the A above middle C is tuned to 440 Hz, or 440 cycles per second. This means that the sound you hear when you play A is vibrating 440 times per second.

Intentional Microtonality

Intentional microtonality is deliberate, chosen, conscious microtonality. This term is inspired by intentional communities, which are communes and other arrangements whereby the residents choose to create or join a community because of the community and not because it just happens to be where they live. Authentic historical revival music and ethnic music are often microtonal, but the microtonality comes as part of the environment. Players playing out of tune may sometimes be called microtonal, but is not intentional. Intentional microtonality is when the composer is aware of microtonality and chooses the tunings for a new piece of music.

Linear Scale

A linear scale is defined with two values: a Repeat Ratio, and a Base Interval. The Base Interval is often called the Generator. If you make a chain of stacked base intervals, such as fifths one on top of another, and then reduce the size of the resulting ratios that are larger than your Repeat Ratio by that Repeat Ratio until they fall within, then you have a linear scale.

You can also slightly stretch, compress, or knead the Base Interval in order to change the entire scale. This process of making a small change to the Base Interval is called tempering. If you have a base interval of a fifth (the ratio of 3/2) and a Repeat Ratio of the octave (2/1) and temper the Base by a quarter of a small interval called a syntonic comma (the ratio of 81/80), you have the famous historical tuning discovered by Pietro Aaron in 1523, which gains pure thirds and sixths in trade for having flattened fifths.

Linear scales tend to generally sound good and are easier to work with because of their consistency and readily recognizable structure, which the human brain seems to understand instantly.

LMSO has a built in graphical editor called the Knead & Fold Appliance for instantly creating and exploring linear and MOS scales.

Microtonal

Technically, microtonal means pertaining to small tones, where presumably a tone means a whole tone of either a 9/8 ratio, or of the 200 cents found on a piano’s whole step (ie, from C to D). Some people enjoy being particular and fussy, and claim that microtonality can not include tunings such as 5 equal steps per octave because it has equal sized steps of 240.0 cents. they then go on to define a cut off point of intervals that are at least smaller than a tone or semitone, or some other somewhat arbitrary choice which is then further debated.

These debates do not make useful distinctions because they don’t help to write music, nor do they have much practical meaning in terms of music practice or listening. Their main purpose seems to be to distract attention away from the practice of making music and focus instead or pre-compositional activities that seem to never culminate in a creative act.

Furthermore, these sorts of definitions eliminate arabic maqams, turkish maqamat, and even many Indian ragas from being microtonal, which is contrary to long established thought.

We define microtonal widely, to be scales that aren’t 12 tone equal temperament, both xenharmonic scales and more conventional diatonic sounding scales based on just, equal, or other types of intervals.

I consider all ethnic tunings to be microtonal. Some don’t agree but what can you do.

Whether historical western tunings are included is a matter of taste. I personally include them but have no conflict those who disagree. Most people readily agree that the Baroque harpsichords which were built with 16, 19 and 31 keys per octave in a variety of tunings are microtonal, but whether the 12 note harpsichords tuned to non-12 are microtonal is controversial to some. I propose that if a ordinary 5-limit just intonation major diatonic scale is microtonal, then certainly a 12 key version of Werkmeister III is microtonal as well.

People interested in stepping outside the conventional can call themselves microtonalists, but to see where things start to get really interesting, you need to try out xenharmonics.

Modulation

Modulation is the change to and subsequent establishment of a particular tonality in music.

Note that I have sidestepped both defining tonality and explaining what it means to establish it, but maybe we can agree on this definition as is, and then move on to deciding what is tonality and what it means to establish it as a separate discussion.

Moment of Symmetry (MOS)

A MOS scale is a linear scale that has exactly two step sizes, a property which is known as Myhill’s property. MOS scales have the property that a given interval size played on a keyboard will have a more predictable pattern of intervals as mapped to a span of keys.

Oven

An Oven is your basic document type in LMSO. It holds your Recipe, which is your the scale of your tuning. And it also holds the Anchor information, which is a key number and a frequency, enabling a fixed pitch reference to the tuning made from your scale so that it can actually be applied to an instrument, retuning it. Ovens also contain scale information such as the author, date of creation, keywords, references, and description of your scale. The Oven also holds information about how the scale will be mapped to your keyboard or other instrument in any of several different useful mapping patterns.

Pleng

Pleng is an Indonesian gamelan term relating to the aesthetic value of avoiding beatless intervals, because these can sound dead and lifeless. Pleng is alive. A good tuning always has pleng. A tuning in which all intervals are so perfectly tuned so as to be beatless, has no pleng and is thus undesirable. Like many Indonesian words, pleng is onomatopoeic — it sounds like what it describes: plennnnng, the sound of a nice vibrant shimmer when notes are played together.

Some pleng comes from tuning instruments in an ensemble in pairs, each tuned slightly differently. Another element comes from using somewhat nonoctave repeat intervals. And another part comes from using timbrally derived variations of a scale in each register, keeping the notes in a given register in an ensemble tuned together, but not from register to register. Keeping pleng in a tuning is not arbitrary, but is a sensitive artistic adjustment done by the ear of the gamelan maker working together with the spirit of the gamelan to achieve harmony.

The aesthetic value of Pleng is something to keep in mind when using electronic tones that have harmonic overtone series, since using mathematically precise just intervals with perfectly harmonic timbres can make an instrument sound reedy and static like an organ.

Ratio

A ratio is a fraction. In music, two relationship between two notes that are played together, a dyad, can be represented by the ratio of their fundamental frequencies. So if you play a note with a fundamental at 440 Hz together with a note with a fundamental at 660 Hz, the ratio between the two is 660 Hz / 440 Hz, which reduces to 3/2. (440 * 3/2 = 660). A ratio of 3/2 is a just intonation fifth, and the given example is that of Western Concert A (440Hz) being played together with the E that is a just fifth above it.

Sometimes when we mean to specify a relative ratio rather than an absolute pitch reference, we’ll use the ratio operator ':' instead of the fractional operator '/'. So we might say that E is 3:2 above A. If A in our scale is also the tonic of the scale, which we often represent as a ratio of 1/1, then we could say the E is tuned to 3/2.

Recipe

In LMSO, a Recipe consists of a Scale Pattern and a Repeat Ratio. A Scale Pattern which can be specified in any of a number of units, such as equal divisions called srutis, ratios of integers or frequencies, or cents. The Scale Pattern is repeated at the Repeat Ratio in order to create a tuning, which is done when you “Bake” your Recipe in the Oven.

Rational Intonation

A rational intonation is a just intonation that uses higher order elements of the harmonic scale, elements which are normally disregarded as containing so little sound energy as to be irrelevant as far as western acoustics theory is concerned.

As an example, if a just intonation scale contains ratios involving numbers like 23 and 37, it is a rational intonation. There is no particular cut off point, though it would be reasonable to say that scales involving factors of 7 and less are just intonation and scales involving factors of 17 and above are rational.

Contrary to common belief, it is not difficult to identify ratios such as 24/23 by ear.

Repeat Ratio

Also known as the Interval of Equivalence or IoE, a scale spans one such ratio and repeats at that ratio up and down to become a tuning. The most common Repeat Ratio in modern tunings is the octave of 2/1, or a stretched or compressed version of it. Scales that do not repeat at the octave can be considered nonoctave scales.

Scale

A single instance of a tuning’s underlying pattern, if any. For example, do re mi fa sol la ti do is the major scale. If you repeat that scale over and over again, you have a tuning.

Scale Fetishism

Scale fetishism is an obsessive fixation on scales themselves as ritual objects. Scales become objects to accumulate and surround oneself with, rather than tools or friends to work with in harmony to accomplish something greater than either contributes alone.

Scale fetishism can be seen in the composer who amasses 10,000 microtonal scales and becomes obsessed with the task of to listening to all of them briefly before making a determination which of the scales are “good” and which are “bad”. These unfortunate scale addicts may feel that there are never enough scales and they need to acquire more. But acquisition of new scales only brings a brief euphoria before the cravings return.

Some victims have even been known to attempt to listen to every combination of scale with every patch or sound available from a similarly obese library of sounds, creating an impossibly large set of combinations, weighing themselves down with the Sisyphian task of mixturing them in every possible interaction.

Many of those seduced with this siren song never return from the sea of scales they have sailed into. The practice also tends to dehumanize the scales, reducing them to objects to be judged.

It is not really possible to find out what a scale is capable of so quickly. You have to get to know it, go out on dates, at the very least write a piece of music with the scale before you can even begin to have a hope of starting to understand its depth, complexity and nuances.

Tonality

Tonality is a perception in the listener of a sense of a key center.

Tonality includes both an established tonic note (called the key center or tonal center) at a specific pitch, and the scale that is anchored to that pitch.

The composer uses the resources of the scale to support the perception in the listener of that pitch as the tonal center.

This definition defers issues of how that key center is perceived by the listener, how it is conveyed by the composer, and how modulation (whatever that is) works to establish a new tonality after a previous one was established.

Tuning

A mapping of specific pitches to all the keys or actuators of a musical instrument.

Tuning Psychosis

Sometimes a composer will become deeply involved with a number of tunings at once, maybe as few as a dozen. Exposure to new tunings leads to new neural interwiring within the brain. Harmless hallucinations are not uncommon, such as seeing colours more brightly, or food tasting different.

But on occasion, one will become agitated, or acquire a sense that the world is not real (this is also known as depersonalization). They may begin to hear voices or experience strange thoughts. They may become argumentative.

This is known as Tuning Psychosis. If a composer starts to become angry with the world after working with many tunings, have him pull back and just work with one tuning for a while, or take a break altogether. Give the brain time to integrate what it has learned into its neural interconnection matrix.

Xenharmonic

From the Greek ξενία (xenia, hospitality) and ξένος (xenos, foreign), Hospitable Harmony and also Alien Harmony. Refers to tunings that are hospitable to new harmonies, and thus do not sound like standard western tunings.

It is popular practice to create low limit just intonation scales that approximate or substitute for standard Western tunings. These scales are microtonal, but not xenharmonic.

If you find yourself writing a piece in 12 equal, and then after the fact you try out different tunings to what you have written and most listeners can’t tell the difference, then your piece is not xenharmonic. Which is fine. But the idea of xenharmonic is that has an intangible property in that it sounds noticeably different. After you work with tunings a while, you’ll know xenharmonic when you hear it. It doesn’t mean dissonant though, it just means different.

Xentonality

1. The use of unconventional keys and harmony within a musical composition.
2. The correlation of timbres and tunings within a musical composition.