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Scale 1153: "CHOian"

Scale 1153: CHOian, 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.

3 (tritonic)

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: 37


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

0 (anhemitonic)


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 Starr/Rahn algorithm.

prime: 37


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.

[7, 3, 2]

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.

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

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, 0.5, 0.5, 0, 0.5, 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> = {2,3,7}
<2> = {5,9,10}

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.

(1, 0, 6)

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

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 1153 can be rotated to make 2 other scales. The 1st mode is itself.

2nd mode:
Scale 41
Scale 41: Vietnamese Tritonic, Ian Ring Music TheoryVietnamese Tritonic
3rd mode:
Scale 517
Scale 517: ALUian, Ian Ring Music TheoryALUian


The prime form of this scale is Scale 37

Scale 37Scale 37: Akha 3 Tone, Ian Ring Music TheoryAkha 3 Tone


The tritonic modal family [1153, 41, 517] (Forte: 3-7) is the complement of the enneatonic modal family [1471, 1789, 2027, 2783, 3061, 3439, 3767, 3931, 4013] (Forte: 9-7)


The inverse of a scale is a reflection using the root as its axis. The inverse of 1153 is 37

Scale 37Scale 37: Akha 3 Tone, Ian Ring Music TheoryAkha 3 Tone


Only scales that are chiral will have an enantiomorph. Scale 1153 is chiral, and its enantiomorph is scale 37

Scale 37Scale 37: Akha 3 Tone, Ian Ring Music TheoryAkha 3 Tone


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> 1153       T0I <11,0> 37
T1 <1,1> 2306      T1I <11,1> 74
T2 <1,2> 517      T2I <11,2> 148
T3 <1,3> 1034      T3I <11,3> 296
T4 <1,4> 2068      T4I <11,4> 592
T5 <1,5> 41      T5I <11,5> 1184
T6 <1,6> 82      T6I <11,6> 2368
T7 <1,7> 164      T7I <11,7> 641
T8 <1,8> 328      T8I <11,8> 1282
T9 <1,9> 656      T9I <11,9> 2564
T10 <1,10> 1312      T10I <11,10> 1033
T11 <1,11> 2624      T11I <11,11> 2066
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 2053      T0MI <7,0> 1027
T1M <5,1> 11      T1MI <7,1> 2054
T2M <5,2> 22      T2MI <7,2> 13
T3M <5,3> 44      T3MI <7,3> 26
T4M <5,4> 88      T4MI <7,4> 52
T5M <5,5> 176      T5MI <7,5> 104
T6M <5,6> 352      T6MI <7,6> 208
T7M <5,7> 704      T7MI <7,7> 416
T8M <5,8> 1408      T8MI <7,8> 832
T9M <5,9> 2816      T9MI <7,9> 1664
T10M <5,10> 1537      T10MI <7,10> 3328
T11M <5,11> 3074      T11MI <7,11> 2561

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 1155Scale 1155: ADWian, Ian Ring Music TheoryADWian
Scale 1157Scale 1157: ALKian, Ian Ring Music TheoryALKian
Scale 1161Scale 1161: Bi Yu, Ian Ring Music TheoryBi Yu
Scale 1169Scale 1169: Raga Mahathi, Ian Ring Music TheoryRaga Mahathi
Scale 1185Scale 1185: Genus Primum Inverse, Ian Ring Music TheoryGenus Primum Inverse
Scale 1217Scale 1217: HICian, Ian Ring Music TheoryHICian
Scale 1025Scale 1025: Warao Ditonic, Ian Ring Music TheoryWarao Ditonic
Scale 1089Scale 1089: GOCian, Ian Ring Music TheoryGOCian
Scale 1281Scale 1281: HUQian, Ian Ring Music TheoryHUQian
Scale 1409Scale 1409: IMSian, Ian Ring Music TheoryIMSian
Scale 1665Scale 1665: KEJian, Ian Ring Music TheoryKEJian
Scale 129Scale 129: Niagari, Ian Ring Music TheoryNiagari
Scale 641Scale 641: Lahuzu 3 Tone Type 1, Ian Ring Music TheoryLahuzu 3 Tone Type 1
Scale 2177Scale 2177: Major Seventh Omit 3, Ian Ring Music TheoryMajor Seventh Omit 3
Scale 3201Scale 3201: URTian, Ian Ring Music TheoryURTian

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.