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# Scale 2921: "Pogian" ### 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).

Zeitler
Pogian
Dozenal
Opsian

## Analysis

#### Cardinality

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

7 (heptatonic)

#### Pitch Class Set

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

{0,3,5,6,8,9,11}

#### Forte Number

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

7-31

#### Rotational Symmetry

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

none

#### 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.

none

#### Palindromicity

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

no

#### Chirality

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

yes
enantiomorph: 731

#### Hemitonia

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

3 (trihemitonic)

#### Cohemitonia

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

0 (ancohemitonic)

#### Imperfections

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.

4

#### Modes

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.

6

#### Prime Form

Describes if this scale is in prime form, using the Rahn/Ring formula.

no
prime: 731

#### Generator

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

none

#### Deep Scale

A deep scale is one where the interval vector has 6 different digits.

no

#### Interval Structure

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

[3, 2, 1, 2, 1, 2, 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, 3, 6, 3, 3, 3>

#### Interval Spectrum

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

p3m3n6s3d3t3

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

#### Spectra Variation

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

1.714

#### Maximally Even

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

no

#### 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.

no

#### 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.

2.549

#### Polygon Perimeter

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

5.967

#### Myhill Property

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

no

#### Balanced

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.

no

#### 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.

none

#### Propriety

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".

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.

(4, 27, 84)

## Tertian Harmonic Chords

Tertian chords are made from alternating members of the scale, ie built from "stacked thirds". Not all scales lend themselves well to tertian harmony. 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

G♯{8,0,3}431.6
B{11,3,6}331.8
g♯m{8,11,3}331.7
d♯°{3,6,9}232
{5,8,11}232
f♯°{6,9,0}232
{9,0,3}231.9

view full size

Above is a graph showing opportunities for parsimonious voice leading between triads*. Each line connects two triads that have two common tones, while the third tone changes by one generic scale step.

Diameter 3 3 yes

## Modes

Modes are the rotational transformation of this scale. Scale 2921 can be rotated to make 6 other scales. The 1st mode is itself.

 2nd mode:Scale 877 Moravian Pistalkova 3rd mode:Scale 1243 Epylian 4th mode:Scale 2669 Jeths' Mode 5th mode:Scale 1691 Kathian 6th mode:Scale 2893 Lylian 7th mode:Scale 1747 Mela Ramapriya

## Prime

The prime form of this scale is Scale 731

 Scale 731 Alternating Heptamode

## Complement

The heptatonic modal family [2921, 877, 1243, 2669, 1691, 2893, 1747] (Forte: 7-31) is the complement of the pentatonic modal family [587, 601, 713, 1609, 2341] (Forte: 5-31)

## Inverse

The inverse of a scale is a reflection using the root as its axis. The inverse of 2921 is 731

 Scale 731 Alternating Heptamode

## Enantiomorph

Only scales that are chiral will have an enantiomorph. Scale 2921 is chiral, and its enantiomorph is scale 731

 Scale 731 Alternating Heptamode

## Transformations:

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> 2921       T0I <11,0> 731
T1 <1,1> 1747      T1I <11,1> 1462
T2 <1,2> 3494      T2I <11,2> 2924
T3 <1,3> 2893      T3I <11,3> 1753
T4 <1,4> 1691      T4I <11,4> 3506
T5 <1,5> 3382      T5I <11,5> 2917
T6 <1,6> 2669      T6I <11,6> 1739
T7 <1,7> 1243      T7I <11,7> 3478
T8 <1,8> 2486      T8I <11,8> 2861
T9 <1,9> 877      T9I <11,9> 1627
T10 <1,10> 1754      T10I <11,10> 3254
T11 <1,11> 3508      T11I <11,11> 2413
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 731      T0MI <7,0> 2921
T1M <5,1> 1462      T1MI <7,1> 1747
T2M <5,2> 2924      T2MI <7,2> 3494
T3M <5,3> 1753      T3MI <7,3> 2893
T4M <5,4> 3506      T4MI <7,4> 1691
T5M <5,5> 2917      T5MI <7,5> 3382
T6M <5,6> 1739      T6MI <7,6> 2669
T7M <5,7> 3478      T7MI <7,7> 1243
T8M <5,8> 2861      T8MI <7,8> 2486
T9M <5,9> 1627      T9MI <7,9> 877
T10M <5,10> 3254      T10MI <7,10> 1754
T11M <5,11> 2413      T11MI <7,11> 3508

The transformations that map this set to itself are: T0, T0MI

## 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 2923 Baryllic Scale 2925 Diminished Scale 2913 Senian Scale 2917 Nohkan Flute Scale Scale 2929 Aeolathian Scale 2937 Phragyllic Scale 2889 Thoptimic Scale 2905 Aeolian Flat 1 Scale 2857 Stythimic Scale 2985 Epacrian Scale 3049 Phrydyllic Scale 2665 Aeradimic Scale 2793 Eporian Scale 2409 Zacrimic Scale 3433 Thonian Scale 3945 Lydyllic Scale 873 Bagimic Scale 1897 Ionopian

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 (http://allthescales.org) 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.