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# Scale 2551: "Thocrygic" ### 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
Thocrygic
Dozenal
Poxian

## Analysis

#### Cardinality

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

9 (enneatonic)

#### Pitch Class Set

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

{0,1,2,4,5,6,7,8,11}

#### Forte Number

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

9-5

#### 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: 3571

#### Hemitonia

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

7 (multihemitonic)

#### Cohemitonia

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

5 (multicohemitonic)

#### 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.

2

#### 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.

8

#### Prime Form

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

no
prime: 991

#### 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.

[1, 1, 2, 1, 1, 1, 1, 3, 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.

<7, 6, 6, 6, 7, 4>

#### Interval Spectrum

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

p7m6n6s6d7t4

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

#### Spectra Variation

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

1.778

#### 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.

2.683

#### Polygon Perimeter

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

6.038

#### 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.

(28, 94, 180)

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

C♯{1,5,8}342.29
E{4,8,11}442.07
G{7,11,2}342.36
em{4,7,11}342.14
fm{5,8,0}342.21
bm{11,2,6}242.64
{2,5,8}242.57
{5,8,11}242.43
g♯°{8,11,2}242.43
{11,2,5}242.71

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 4 4 yes

## Modes

Modes are the rotational transformation of this scale. Scale 2551 can be rotated to make 8 other scales. The 1st mode is itself.

 2nd mode:Scale 3323 Lacrygic 3rd mode:Scale 3709 Katynygic 4th mode:Scale 1951 Marygic 5th mode:Scale 3023 Mothygic 6th mode:Scale 3559 Thophygic 7th mode:Scale 3827 Bodygic 8th mode:Scale 3961 Zathygic 9th mode:Scale 1007 Epitygic

## Prime

The prime form of this scale is Scale 991

 Scale 991 Aeolygic

## Complement

The enneatonic modal family [2551, 3323, 3709, 1951, 3023, 3559, 3827, 3961, 1007] (Forte: 9-5) is the complement of the tritonic modal family [67, 193, 2081] (Forte: 3-5)

## Inverse

The inverse of a scale is a reflection using the root as its axis. The inverse of 2551 is 3571

 Scale 3571 Dyrygic

## Enantiomorph

Only scales that are chiral will have an enantiomorph. Scale 2551 is chiral, and its enantiomorph is scale 3571

 Scale 3571 Dyrygic

## 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> 2551       T0I <11,0> 3571
T1 <1,1> 1007      T1I <11,1> 3047
T2 <1,2> 2014      T2I <11,2> 1999
T3 <1,3> 4028      T3I <11,3> 3998
T4 <1,4> 3961      T4I <11,4> 3901
T5 <1,5> 3827      T5I <11,5> 3707
T6 <1,6> 3559      T6I <11,6> 3319
T7 <1,7> 3023      T7I <11,7> 2543
T8 <1,8> 1951      T8I <11,8> 991
T9 <1,9> 3902      T9I <11,9> 1982
T10 <1,10> 3709      T10I <11,10> 3964
T11 <1,11> 3323      T11I <11,11> 3833
Abbrev Operation Result Abbrev Operation Result
T0M <5,0> 3571      T0MI <7,0> 2551
T1M <5,1> 3047      T1MI <7,1> 1007
T2M <5,2> 1999      T2MI <7,2> 2014
T3M <5,3> 3998      T3MI <7,3> 4028
T4M <5,4> 3901      T4MI <7,4> 3961
T5M <5,5> 3707      T5MI <7,5> 3827
T6M <5,6> 3319      T6MI <7,6> 3559
T7M <5,7> 2543      T7MI <7,7> 3023
T8M <5,8> 991      T8MI <7,8> 1951
T9M <5,9> 1982      T9MI <7,9> 3902
T10M <5,10> 3964      T10MI <7,10> 3709
T11M <5,11> 3833      T11MI <7,11> 3323

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 2549 Rydyllic Scale 2547 Raga Ramkali Scale 2555 Bythygic Scale 2559 Decatonic Chromatic 2 Scale 2535 Messiaen Mode 4 Scale 2543 Dydygic Scale 2519 Dathyllic Scale 2487 Dothyllic Scale 2423 Otuian Scale 2295 Kogyllic Scale 2807 Zylygic Scale 3063 Solyllian Scale 3575 Symmetrical Decatonic Scale 503 Thoptyllic Scale 1527 Aeolyrigic

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.