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Scale 2105: "Rigian"

Scale 2105: Rigian, 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.

5 (pentatonic)

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: 899


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

3 (trihemitonic)


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

1 (uncohemitonic)


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.

prime: 103


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.

[3, 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.

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

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

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.

(16, 1, 30)

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 2105 can be rotated to make 4 other scales. The 1st mode is itself.

2nd mode:
Scale 775
Scale 775: Raga Putrika, Ian Ring Music TheoryRaga Putrika
3rd mode:
Scale 2435
Scale 2435: Raga Deshgaur, Ian Ring Music TheoryRaga Deshgaur
4th mode:
Scale 3265
Scale 3265: Urrian, Ian Ring Music TheoryUrrian
5th mode:
Scale 115
Scale 115: Ashian, Ian Ring Music TheoryAshian


The prime form of this scale is Scale 103

Scale 103Scale 103: Apuian, Ian Ring Music TheoryApuian


The pentatonic modal family [2105, 775, 2435, 3265, 115] (Forte: 5-6) is the complement of the heptatonic modal family [415, 995, 2255, 2545, 3175, 3635, 3865] (Forte: 7-6)


The inverse of a scale is a reflection using the root as its axis. The inverse of 2105 is 899

Scale 899Scale 899: Foqian, Ian Ring Music TheoryFoqian


Only scales that are chiral will have an enantiomorph. Scale 2105 is chiral, and its enantiomorph is scale 899

Scale 899Scale 899: Foqian, Ian Ring Music TheoryFoqian


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> 2105       T0I <11,0> 899
T1 <1,1> 115      T1I <11,1> 1798
T2 <1,2> 230      T2I <11,2> 3596
T3 <1,3> 460      T3I <11,3> 3097
T4 <1,4> 920      T4I <11,4> 2099
T5 <1,5> 1840      T5I <11,5> 103
T6 <1,6> 3680      T6I <11,6> 206
T7 <1,7> 3265      T7I <11,7> 412
T8 <1,8> 2435      T8I <11,8> 824
T9 <1,9> 775      T9I <11,9> 1648
T10 <1,10> 1550      T10I <11,10> 3296
T11 <1,11> 3100      T11I <11,11> 2497
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 395      T0MI <7,0> 2609
T1M <5,1> 790      T1MI <7,1> 1123
T2M <5,2> 1580      T2MI <7,2> 2246
T3M <5,3> 3160      T3MI <7,3> 397
T4M <5,4> 2225      T4MI <7,4> 794
T5M <5,5> 355      T5MI <7,5> 1588
T6M <5,6> 710      T6MI <7,6> 3176
T7M <5,7> 1420      T7MI <7,7> 2257
T8M <5,8> 2840      T8MI <7,8> 419
T9M <5,9> 1585      T9MI <7,9> 838
T10M <5,10> 3170      T10MI <7,10> 1676
T11M <5,11> 2245      T11MI <7,11> 3352

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 2107Scale 2107: Mutian, Ian Ring Music TheoryMutian
Scale 2109Scale 2109: Muvian, Ian Ring Music TheoryMuvian
Scale 2097Scale 2097: Munian, Ian Ring Music TheoryMunian
Scale 2101Scale 2101: Muqian, Ian Ring Music TheoryMuqian
Scale 2089Scale 2089: Mujian, Ian Ring Music TheoryMujian
Scale 2073Scale 2073: Moyian, Ian Ring Music TheoryMoyian
Scale 2137Scale 2137: Nalian, Ian Ring Music TheoryNalian
Scale 2169Scale 2169: Nefian, Ian Ring Music TheoryNefian
Scale 2233Scale 2233: Donimic, Ian Ring Music TheoryDonimic
Scale 2361Scale 2361: Docrimic, Ian Ring Music TheoryDocrimic
Scale 2617Scale 2617: Pylimic, Ian Ring Music TheoryPylimic
Scale 3129Scale 3129: Toqian, Ian Ring Music TheoryToqian
Scale 57Scale 57: Ahoian, Ian Ring Music TheoryAhoian
Scale 1081Scale 1081: Goxian, Ian Ring Music TheoryGoxian

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.