Porcupine: Difference between revisions

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'''Porcupine''' is a [[linear temperament]] in the [[porcupine family]] that tempers out [[250/243]], the porcupine [[comma]], and whose generator is usually around 160–165 [[cent]]s. It can be thought of as a [[5-limit]], [[7-limit]], or [[11-limit]] temperament, or a 2.3.5.11 [[subgroup temperament]]. It is one of the best temperaments in the 2.3.5.11 subgroup, with a unique combination of efficiency and accuracy.
'''Porcupine''' is a [[linear temperament]] in the [[porcupine family]] that tempers out [[250/243]], the porcupine [[comma]], and whose generator is usually around 160–165 [[cent]]s. It can be thought of as a [[5-limit]], [[7-limit]], or [[11-limit]] temperament, or a 2.3.5.11 [[subgroup temperament]]. It is one of the best temperaments in the 2.3.5.11 subgroup, with a unique combination of efficiency and accuracy.


The basic 5-limit harmonic structure of porcupine can be understood simply by noting that tempering out 250/243 makes (4/3)<sup>2</sup> equivalent to (6/5)<sup>3</sup>. In perhaps more familiar musical terms, this means two "perfect fourths" equals three "minor thirds". As a consequence of this, 4/3 is divided into 3 equal parts, and 6/5 is divided into 2 of those same equal parts. This is obviously in stark contrast to [[12edo]], and to meantone, in which neither 4/3 nor 6/5 can be divided into any number of equal parts. The "equal tetrachord" formed by dividing 4/3 into 3 equal parts is a characteristic feature of many porcupine scales.
The basic 5-limit harmonic structure of porcupine can be understood simply by noting that tempering out 250/243 makes (4/3)<sup>2</sup> equivalent to (6/5)<sup>3</sup>. In perhaps more familiar musical terms, this means two "perfect fourths" equals three "minor thirds". As a consequence of this, 4/3 is divided into 3 equal parts, and 6/5 is divided into 2 of those same equal parts. This is obviously in stark contrast to [[12edo]], and to [[meantone]], in which neither 4/3 nor 6/5 can be divided into any number of equal parts. The "equal tetrachord" formed by dividing 4/3 into 3 equal parts is a characteristic feature of many porcupine scales.


== Interval chain ==
== Interval chain ==
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! Cents
! Cents
! Ratios
! Ratios
! Ups and Downs <br> notation
! Ups and Downs <br> Notation
! #
! #
! 2/1 inverse
! 2/1 inverse
! Ratios
! Ratios
! Ups and Downs <br> notation
! Ups and Downs <br> Notation
|-
|-
| 0
| 0
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{| class="wikitable center-all left-4"
{| class="wikitable center-all left-4"
|+ Tuning spectrum of 13-limit porcupine
|+ Tuning spectrum of 13-limit porcupine
! EDO<br>generator
! Edo<br>generator
! [[eigenmonzo|eigenmonzo<br>(unchanged-interval)]]
! [[Eigenmonzo|Eigenmonzo<br>(Unchanged-Interval)]]
! generator (¢)
! Generator (¢)
! comments
! Comments
|-
|-
|  
|  
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{| class="wikitable center-all"
{| class="wikitable center-all"
|+ Tuning spectrum of porcupinefish
|+ Tuning spectrum of porcupinefish
! EDO<br>generator
! Edo<br>generator
! eigenmonzo<br>(unchanged-interval)
! Eigenmonzo<br>(Unchanged-Interval)
! generator (¢)
! Generator (¢)
! comments
! Comments
|-
|-
|  
|  
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== Music ==
== Music ==
; [[Herman Miller]]
; [[Herman Miller]]
* ''[https://sites.google.com/site/teamouse/home#TOC-Mizarian-music ''Mizarian Porcupine Overture'']'' (1999) – in [[15edo]], namesake of the temperament
* [https://sites.google.com/site/teamouse/home#TOC-Mizarian-music ''Mizarian Porcupine Overture''] (1999) – in [[15edo]], namesake of the temperament


; [[Paul Erlich]]
; [[Paul Erlich]]