Ploidacot: Difference between revisions
Improve details |
No edit summary |
||
(10 intermediate revisions by 5 users not shown) | |||
Line 5: | Line 5: | ||
== Specification == | == Specification == | ||
=== Ploids === | === Ploids === | ||
Any rank-2 temperament of the 2.3.… subgroup has an octave, and it | Any rank-2 temperament of the 2.3.… subgroup has an octave, and it may split the octave into a number of parts, or [[period]]s, called '''ploids'''. The temperament's number of ploids per octave is specified by a Greek numeral prefix (di-, tri-, etc.) and -ploid. For instance, pajara divides the octave into two, so it is diploid. Temperaments that do not divide the octave are called haploid (''not'' *monoploid), which can be omitted. | ||
=== Cots === | === Cots === | ||
Line 69: | Line 69: | ||
== Properties == | == Properties == | ||
* For ''n''-cot systems there are exactly ''n'' settings of shear, or number of ploids to add to the step that represents the interval class of 3. The possible values of shear are 0, 1, 2, …, {{nowrap|(''n'' − 1)}}. For example, the tricot systems are tricot (0-sheared), alpha-tricot (1-sheared), and beta-tricot (2-sheared). There is not a *gamma-tricot since that would be equivalent to tricot. | |||
== Extensions == | |||
=== Omega extension === | |||
The Greek letter omega, proposed by [[User:Godtone|Godtone]], is used for −1. This simplifies the classification of certain temperaments, e.g. porcupine, which instead of beta-tricot can be omega-tricot, as splitting the interval 4/3 into three is arguably more intuitive than splitting the interval 6. This effectively shifts the possible values of shear to -1, 0, 1, …, {{nowrap|(''n'' − 2)}} if ''n'' ≥ 3. | |||
Note that omega should only be used with {{nowrap| ''n'' ≥ 3 }}. When {{nowrap| ''n'' {{=}} 1 }}, there is only monocot. When {{nowrap| ''n'' {{=}} 2 }}, alpha-dicot is preferred over omega-dicot. | |||
=== Non-octave temperaments === | |||
{{Todo|inline=1| expand }} | |||
== Examples == | == Examples == | ||
* [[Meantone]] and [[ | The ploidacots of most common temperaments can be intuitively derived from a basic understanding of its mapping. [[Meantone]] and [[Helmholtz (temperament)|helmholtz]] are monocot since they have a period of a whole octave and are generated by the perfect fifth. Dicot is dicot since it has a period of a whole octave and splits the perfect fifth in two. Semaphore has a period of a whole octave and splits the perfect twelfth in two. It requires one period to add to the fifth to make it a twelfth, and one is alpha. So it is alpha-dicot. | ||
* [[Mohajira]] and [[ | |||
For a more complex example, let us consider sensi and its weak extension bison. Sensi splits 6/1 in seven. It requires two periods to the fifth to reach 6/1, and two is beta. So it is beta-heptacot. Bison splits the period of sensi in two. As a result, it now requires four periods to the fifth to reach 6/1, and four is delta. So it is diploid delta-heptacot. | |||
Below is a list of ploidacots for common temperaments | |||
* [[Meantone]] and [[Helmholtz (temperament)|helmholtz]] are haploid monocot | |||
* [[Mohajira]] and [[dicot]] are dicot | |||
* [[Bug]] and [[semaphore]] are alpha-dicot | * [[Bug]] and [[semaphore]] are alpha-dicot | ||
* [[Shrutar]] is diploid alpha-dicot | * [[Shrutar]] is diploid alpha-dicot | ||
* [[Ennealimmal]] is enneaploid dicot | * [[Ennealimmal]] is enneaploid dicot | ||
* [[Hemiennealimmal]] is octodecaploid (18-ploid) dicot | * [[Hemiennealimmal]] is octodecaploid (18-ploid) dicot | ||
* [[Slendric]], [[ | * [[Slendric]], [[mothra]], and [[rodan]] are tricot | ||
* [[ | * [[Alphatricot]] is alpha-tricot | ||
* [[Porcupine]] is beta-tricot | * [[Porcupine]] is beta-tricot | ||
* [[Hedgehog]] is diploid alpha-tricot | * [[Hedgehog]] is diploid alpha-tricot | ||
Line 93: | Line 107: | ||
* [[Sensi]] is beta-heptacot | * [[Sensi]] is beta-heptacot | ||
* [[Vishnu]] is diploid epsilon-heptacot | * [[Vishnu]] is diploid epsilon-heptacot | ||
* [[ | * [[Octacot]] is octacot | ||
* [[ | * [[Würschmidt]] is beta-octacot | ||
* [[Valentine]] is enneacot | * [[Valentine]] is enneacot | ||
* [[ | * [[Sycamore]] is hendecacot | ||
* [[ | * [[Chromo]] is tridecacot | ||
* [[Pajara]] and [[ | * [[Pajara]] and [[injera]] are diploid | ||
* [[ | * [[Antitonic]] is diploid acot | ||
* [[Augene]] is triploid | * [[Augene]] is triploid | ||
* [[Diminished]] is tetraploid | * [[Diminished]] is tetraploid | ||
* [[Blackwood]] is pentaploid acot | * [[Blackwood]] is pentaploid acot | ||
* [[ | * [[Whitewood]] is heptaploid acot | ||
* [[Ennealimmal]] is enneaploid | * [[Ennealimmal]] is enneaploid | ||
* [[Compton]] is dodecaploid acot | * [[Compton]] is dodecaploid acot | ||
Line 109: | Line 123: | ||
== Notation == | == Notation == | ||
: ''TODO: Come up with canonical ups and downs notation systems for pergen squares'' | : ''TODO: Come up with canonical ups and downs notation systems for pergen squares'' | ||
== List of ploidacots == | |||
=== Acot === | |||
* Pentaploid acot ([[blackwood]], [[5edo]]) | |||
* Heptaploid acot ([[whitewood]], [[7edo]]) | |||
* Dodecaploid acot ([[compton]], [[12edo]]) | |||
=== Monocot === | |||
* [[Ploidacot/Monocot|Monocot]] | |||
* [[Ploidacot/Diploid monocot|Diploid monocot]] | |||
* [[Ploidacot/Triploid monocot|Triploid monocot]] | |||
* [[Ploidacot/Tetraploid monocot|Tetraploid monocot]] | |||
=== Dicot === | |||
* [[Ploidacot/Dicot|Dicot]] | |||
* [[Ploidacot/Alpha-dicot|Alpha-dicot]] | |||
* [[Ploidacot/Diploid dicot|Diploid dicot]] | |||
=== Tricot === | |||
* [[Ploidacot/Tricot|Tricot]] | |||
* [[Ploidacot/Alpha-tricot|Alpha-tricot]] | |||
* [[Ploidacot/Diploid alpha-tricot|Diploid alpha-tricot]] | |||
* [[Ploidacot/Omega-tricot|Omega-tricot]] | |||
=== Tetracot === | |||
* [[Ploidacot/Tetracot|Tetracot]] | |||
* [[Ploidacot/Alpha-tetracot|Alpha-tetracot]] | |||
* [[Ploidacot/Beta-tetracot|Beta-tetracot]] | |||
* [[Ploidacot/Omega-tetracot|Omega-tetracot]] | |||
=== Pentacot === | |||
* [[Ploidacot/Pentacot|Pentacot]] | |||
* [[Ploidacot/Alpha-pentacot|Alpha-pentacot]] | |||
* [[Ploidacot/Gamma-pentacot|Gamma-pentacot]] | |||
=== Hexacot === | |||
* [[Ploidacot/Hexacot|Hexacot]] | |||
* [[Ploidacot/Alpha-hexacot|Alpha-hexacot]] | |||
=== Heptacot === | |||
* [[Ploidacot/Heptacot|Heptacot]] | |||
* [[Ploidacot/Alpha-heptacot|Alpha-heptacot]] | |||
* [[Ploidacot/Beta-heptacot|Beta-heptacot]] | |||
=== Octacot === | |||
* [[Ploidacot/Octacot|Octacot]] | |||
* [[Ploidacot/Beta-octacot|Beta-octacot]] | |||
=== Enneacot === | |||
* [[Ploidacot/Enneacot|Enneacot]] | |||
=== >10 cots === | |||
* [[Ploidacot/Icosacot|Icosacot]] | |||
== See also == | |||
* [[Wedgie]] - a mathematical generalization of the concept of ploidacots that uniquely characterizes a temperament | |||
[[Category:Temperament naming]] | [[Category:Temperament naming]] |