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Scale 27: "Adoian"

Scale 27: Adoian, 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).

Common Names




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

4 (tetratonic)

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.



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

2 (dihemitonic)


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

0 (ancohemitonic)


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 Rahn/Ring formula.



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.


Interval Structure

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

[1, 2, 1, 8]

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.

<2, 1, 2, 1, 0, 0>

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

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 Interval Spectra has 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.

(5, 0, 14)

Common Triads

There are no common triads (major, minor, augmented and diminished) that can be formed using notes in this scale.


Modes are the rotational transformation of this scale. Scale 27 can be rotated to make 3 other scales. The 1st mode is itself.

2nd mode:
Scale 2061
Scale 2061: Morian, Ian Ring Music TheoryMorian
3rd mode:
Scale 1539
Scale 1539: Jikian, Ian Ring Music TheoryJikian
4th mode:
Scale 2817
Scale 2817, Ian Ring Music Theory


This is the prime form of this scale.


The tetratonic modal family [27, 2061, 1539, 2817] (Forte: 4-3) is the complement of the octatonic modal family [639, 1017, 2367, 3231, 3663, 3879, 3987, 4041] (Forte: 8-3)


The inverse of a scale is a reflection using the root as its axis. The inverse of 27 is 2817

Scale 2817Scale 2817, Ian Ring Music Theory


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> 27       T0I <11,0> 2817
T1 <1,1> 54      T1I <11,1> 1539
T2 <1,2> 108      T2I <11,2> 3078
T3 <1,3> 216      T3I <11,3> 2061
T4 <1,4> 432      T4I <11,4> 27
T5 <1,5> 864      T5I <11,5> 54
T6 <1,6> 1728      T6I <11,6> 108
T7 <1,7> 3456      T7I <11,7> 216
T8 <1,8> 2817      T8I <11,8> 432
T9 <1,9> 1539      T9I <11,9> 864
T10 <1,10> 3078      T10I <11,10> 1728
T11 <1,11> 2061      T11I <11,11> 3456
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 297      T0MI <7,0> 657
T1M <5,1> 594      T1MI <7,1> 1314
T2M <5,2> 1188      T2MI <7,2> 2628
T3M <5,3> 2376      T3MI <7,3> 1161
T4M <5,4> 657      T4MI <7,4> 2322
T5M <5,5> 1314      T5MI <7,5> 549
T6M <5,6> 2628      T6MI <7,6> 1098
T7M <5,7> 1161      T7MI <7,7> 2196
T8M <5,8> 2322      T8MI <7,8> 297
T9M <5,9> 549      T9MI <7,9> 594
T10M <5,10> 1098      T10MI <7,10> 1188
T11M <5,11> 2196      T11MI <7,11> 2376

The transformations that map this set to itself are: T0, T4I

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 25Scale 25: Ackian, Ian Ring Music TheoryAckian
Scale 29Scale 29: Aduian, Ian Ring Music TheoryAduian
Scale 31Scale 31: Pentatonic Chromatic, Ian Ring Music TheoryPentatonic Chromatic
Scale 19Scale 19: Acuian, Ian Ring Music TheoryAcuian
Scale 23Scale 23: Aphian, Ian Ring Music TheoryAphian
Scale 11Scale 11: Ankian, Ian Ring Music TheoryAnkian
Scale 43Scale 43: Alfian, Ian Ring Music TheoryAlfian
Scale 59Scale 59: Ahuian, Ian Ring Music TheoryAhuian
Scale 91Scale 91: Anoian, Ian Ring Music TheoryAnoian
Scale 155Scale 155: Bakian, Ian Ring Music TheoryBakian
Scale 283Scale 283: Aerylitonic, Ian Ring Music TheoryAerylitonic
Scale 539Scale 539: Delian, Ian Ring Music TheoryDelian
Scale 1051Scale 1051: Gifian, Ian Ring Music TheoryGifian
Scale 2075Scale 2075: Mozian, Ian Ring Music TheoryMozian

This scale analysis was created by Ian Ring, Canadian Composer of works for Piano, and total music theory nerd. Scale notation generated by VexFlow, graph visualization by Graphviz, and MIDI playback by MIDI.js. 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.