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Scale 2109: "MUVian"

Scale 2109: MUVian, Ian Ring Music Theory

Bracelet Diagram

The bracelet shows tones that are in this scale, starting from the top (12 o'clock), going clockwise in ascending semitones. The "i" icon marks imperfect tones that do not have a tone a fifth above. Dotted lines indicate axes of symmetry.

Tonnetz Diagram

Tonnetz diagrams are popular in Neo-Riemannian theory. Notes are arranged in a lattice where perfect 5th intervals are from left to right, major third are northeast, and major 6th intervals are northwest. Other directions are inverse of their opposite. This diagram helps to visualize common triads (they're triangles) and circle-of-fifth relationships (horizontal lines).



Cardinality is the count of how many pitches are in the scale.

6 (hexatonic)

Pitch Class Set

The tones in this scale, expressed as numbers from 0 to 11


Forte Number

A code assigned by theorist Allen Forte, for this pitch class set and all of its transpositional (rotation) and inversional (reflection) transformations.


Rotational Symmetry

Some scales have rotational symmetry, sometimes known as "limited transposition". If there are any rotational symmetries, these are the intervals of periodicity.


Reflection Axes

If a scale has an axis of reflective symmetry, then it can transform into itself by inversion. It also implies that the scale has Ridge Tones. Notably an axis of reflection can occur directly on a tone or half way between two tones.



A palindromic scale has the same pattern of intervals both ascending and descending.



A chiral scale can not be transformed into its inverse by rotation. If a scale is chiral, then it has an enantiomorph.

enantiomorph: 1923


A hemitone is two tones separated by a semitone interval. Hemitonia describes how many such hemitones exist.

4 (multihemitonic)


A cohemitone is an instance of two adjacent hemitones. Cohemitonia describes how many such cohemitones exist.

2 (dicohemitonic)


An imperfection is a tone which does not have a perfect fifth above it in the scale. This value is the quantity of imperfections in this scale.



Modes are the rotational transformations of this scale. This number does not include the scale itself, so the number is usually one less than its cardinality; unless there are rotational symmetries then there are even fewer modes.


Prime Form

Describes if this scale is in prime form, using the Starr/Rahn algorithm.

prime: 111


Indicates if the scale can be constructed using a generator, and an origin.


Deep Scale

A deep scale is one where the interval vector has 6 different digits, an indicator of maximum hierarchization.


Interval Structure

Defines the scale as the sequence of intervals between one tone and the next.

[2, 1, 1, 1, 6, 1]

Interval Vector

Describes the intervallic content of the scale, read from left to right as the number of occurences of each interval size from semitone, up to six semitones.

<4, 3, 3, 2, 2, 1>

Proportional Saturation Vector

First described by Michael Buchler (2001), this is a vector showing the prominence of intervals relative to the maximum and minimum possible for the scale's cardinality. A saturation of 0 means the interval is present minimally, a saturation of 1 means it is the maximum possible.

<0.8, 0.5, 0.6, 0, 0.4, 0.333>

Interval Spectrum

The same as the Interval Vector, but expressed in a syntax used by Howard Hanson.


Distribution Spectra

Describes the specific interval sizes that exist for each generic interval size. Each generic <g> has a spectrum {n,...}. The Spectrum Width is the difference between the highest and lowest values in each spectrum.

<1> = {1,2,6}
<2> = {2,3,7}
<3> = {3,4,8,9}
<4> = {5,9,10}
<5> = {6,10,11}

Spectra Variation

Determined by the Distribution Spectra; this is the sum of all spectrum widths divided by the scale cardinality.


Maximally Even

A scale is maximally even if the tones are optimally spaced apart from each other.


Maximal Area Set

A scale is a maximal area set if a polygon described by vertices dodecimetrically placed around a circle produces the maximal interior area for scales of the same cardinality. All maximally even sets have maximal area, but not all maximal area sets are maximally even.


Interior Area

Area of the polygon described by vertices placed for each tone of the scale dodecimetrically around a unit circle, ie a circle with radius of 1.


Polygon Perimeter

Perimeter of the polygon described by vertices placed for each tone of the scale dodecimetrically around a unit circle.


Myhill Property

A scale has Myhill Property if the Distribution Spectra have exactly two specific intervals for every generic interval.



A scale is balanced if the distribution of its tones would satisfy the "centrifuge problem", ie are placed such that it would balance on its centre point.


Ridge Tones

Ridge Tones are those that appear in all transpositions of a scale upon the members of that scale. Ridge Tones correspond directly with axes of reflective symmetry.



Also known as Rothenberg Propriety, named after its inventor. Propriety describes whether every specific interval is uniquely mapped to a generic interval. A scale is either "Proper", "Strictly Proper", or "Improper".


Heteromorphic Profile

Defined by Norman Carey (2002), the heteromorphic profile is an ordered triple of (c, a, d) where c is the number of contradictions, a is the number of ambiguities, and d is the number of differences. When c is zero, the scale is Proper. When a is also zero, the scale is Strictly Proper.

(34, 9, 55)

Coherence Quotient

The Coherence Quotient is a score between 0 and 1, indicating the proportion of coherence failures (ambiguity or contradiction) in the scale, against the maximum possible for a cardinality. A high coherence quotient indicates a less complex scale, whereas a quotient of 0 indicates a maximally complex scale.


Sameness Quotient

The Sameness Quotient is a score between 0 and 1, indicating the proportion of differences in the heteromorphic profile, against the maximum possible for a cardinality. A higher quotient indicates a less complex scale, whereas a quotient of 0 indicates a scale with maximum complexity.



This scale has no generator.

Common Triads

These are the common triads (major, minor, augmented and diminished) that you can create from members of this scale.

* Pitches are shown with C as the root

Triad TypeTriad*Pitch ClassesDegreeEccentricityCloseness Centrality
Diminished Triads{11,2,5}000

The following pitch classes are not present in any of the common triads: {0,3,4}

Since there is only one common triad in this scale, there are no opportunities for parsimonious voice leading between triads.


Modes are the rotational transformation of this scale. Scale 2109 can be rotated to make 5 other scales. The 1st mode is itself.

2nd mode:
Scale 1551
Scale 1551: JORian, Ian Ring Music TheoryJORian
3rd mode:
Scale 2823
Scale 2823: RULian, Ian Ring Music TheoryRULian
4th mode:
Scale 3459
Scale 3459: VOCian, Ian Ring Music TheoryVOCian
5th mode:
Scale 3777
Scale 3777: YARian, Ian Ring Music TheoryYARian
6th mode:
Scale 123
Scale 123: ASUian, Ian Ring Music TheoryASUian


The prime form of this scale is Scale 111

Scale 111Scale 111: AROian, Ian Ring Music TheoryAROian


The hexatonic modal family [2109, 1551, 2823, 3459, 3777, 123] (Forte: 6-Z3) is the complement of the hexatonic modal family [159, 993, 2127, 3111, 3603, 3849] (Forte: 6-Z36)


The inverse of a scale is a reflection using the root as its axis. The inverse of 2109 is 1923

Scale 1923Scale 1923: LULian, Ian Ring Music TheoryLULian


Only scales that are chiral will have an enantiomorph. Scale 2109 is chiral, and its enantiomorph is scale 1923

Scale 1923Scale 1923: LULian, Ian Ring Music TheoryLULian


In the abbreviation, the subscript number after "T" is the number of semitones of tranposition, "M" means the pitch class is multiplied by 5, and "I" means the result is inverted. Operation is an identical way to express the same thing; the syntax is <a,b> where each tone of the set x is transformed by the equation y = ax + b

Abbrev Operation Result Abbrev Operation Result
T0 <1,0> 2109       T0I <11,0> 1923
T1 <1,1> 123      T1I <11,1> 3846
T2 <1,2> 246      T2I <11,2> 3597
T3 <1,3> 492      T3I <11,3> 3099
T4 <1,4> 984      T4I <11,4> 2103
T5 <1,5> 1968      T5I <11,5> 111
T6 <1,6> 3936      T6I <11,6> 222
T7 <1,7> 3777      T7I <11,7> 444
T8 <1,8> 3459      T8I <11,8> 888
T9 <1,9> 2823      T9I <11,9> 1776
T10 <1,10> 1551      T10I <11,10> 3552
T11 <1,11> 3102      T11I <11,11> 3009
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 1419      T0MI <7,0> 2613
T1M <5,1> 2838      T1MI <7,1> 1131
T2M <5,2> 1581      T2MI <7,2> 2262
T3M <5,3> 3162      T3MI <7,3> 429
T4M <5,4> 2229      T4MI <7,4> 858
T5M <5,5> 363      T5MI <7,5> 1716
T6M <5,6> 726      T6MI <7,6> 3432
T7M <5,7> 1452      T7MI <7,7> 2769
T8M <5,8> 2904      T8MI <7,8> 1443
T9M <5,9> 1713      T9MI <7,9> 2886
T10M <5,10> 3426      T10MI <7,10> 1677
T11M <5,11> 2757      T11MI <7,11> 3354

The transformations that map this set to itself are: T0

Nearby Scales:

These are other scales that are similar to this one, created by adding a tone, removing a tone, or moving one note up or down a semitone.

Scale 2111Scale 2111: Heptatonic Chromatic 2, Ian Ring Music TheoryHeptatonic Chromatic 2
Scale 2105Scale 2105: RIGian, Ian Ring Music TheoryRIGian
Scale 2107Scale 2107: MUTian, Ian Ring Music TheoryMUTian
Scale 2101Scale 2101: MUQian, Ian Ring Music TheoryMUQian
Scale 2093Scale 2093: MULian, Ian Ring Music TheoryMULian
Scale 2077Scale 2077: MOBian, Ian Ring Music TheoryMOBian
Scale 2141Scale 2141: NANian, Ian Ring Music TheoryNANian
Scale 2173Scale 2173: NEHian, Ian Ring Music TheoryNEHian
Scale 2237Scale 2237: Epothian, Ian Ring Music TheoryEpothian
Scale 2365Scale 2365: Sythian, Ian Ring Music TheorySythian
Scale 2621Scale 2621: Ionogian, Ian Ring Music TheoryIonogian
Scale 3133Scale 3133: TOSian, Ian Ring Music TheoryTOSian
Scale 61Scale 61: AJUian, Ian Ring Music TheoryAJUian
Scale 1085Scale 1085: GOZian, Ian Ring Music TheoryGOZian

This scale analysis was created by Ian Ring, Canadian Composer of works for Piano, and total music theory nerd. Scale notation generated by VexFlow and Lilypond, graph visualization by Graphviz, audio by TiMIDIty and FFMPEG. All other diagrams and visualizations are © Ian Ring. Some scale names used on this and other pages are ©2005 William Zeitler ( used with permission.

Pitch spelling algorithm employed here is adapted from a method by Uzay Bora, Baris Tekin Tezel, and Alper Vahaplar. (An algorithm for spelling the pitches of any musical scale) Contact authors Patent owner: Dokuz Eylül University, Used with Permission. Contact TTO

Tons of background resources contributed to the production of this summary; for a list of these peruse this Bibliography. Special thanks to Richard Repp for helping with technical accuracy, and George Howlett for assistance with the Carnatic ragas.