Semaphore–chromatic equivalence continuum: Difference between revisions

From Xenharmonic Wiki
Jump to navigation Jump to search
ArrowHead294 (talk | contribs)
m Mark as mathematical interest. Cleanup.
 
(2 intermediate revisions by one other user not shown)
Line 1: Line 1:
The '''semaphore-chromatic equivalence continuum''' is a continuum of 7-limit rank-3 temperament families which equate a number of [[49/48|semaphore commas (49/48)]] with a [[25/24|classic chromatic semitone (25/24)]]. This continuum is theoretically interesting in that these are all 7-limit rank-3 temperament families supported by [[decimal]] temperament. 
{{Mathematical interest}}


All temperaments in the continuum satisfy (49/48)<sup>''n''</sup> ~ 25/24. Varying ''n'' results in different temperament families listed in the table below. It converges to [[semaphore]] as ''n'' approaches infinity. If we allow non-integer and infinite ''n'', the continuum describes the set of all [[7-limit]] temperament families supported by decimal (due to it being the unique rank-2 temperament that tempers both commas and thus tempers all combinations of them). The just value of ''n'' is approximately 1.9797965913603088..., and temperaments having ''n'' near this value will be more accurate. As this value is so close to 2, temperaments tempering out the [[2401/2400|breedsma (2401/2400)]] are unusually accurate. It is even closer to 196/99, but the equivalent comma, while tiny even for an [[unnoticeable comma]] at 0.004907 cents, is unreasonably complex, with a monzo of {{monzo|-487 -97 -198 392}}.
The '''semaphore–chromatic equivalence continuum''' is a continuum of 7-limit rank-3 temperament families which equate a number of [[49/48|semaphore commas (49/48)]] with a [[25/24|classic chromatic semitone (25/24)]]. This continuum is theoretically interesting in that these are all 7-limit rank-3 temperament families supported by [[decimal]] temperament. 
{| class="wikitable center-1 center-2"
 
|+Temperaments in the continuum
All temperaments in the continuum satisfy {{nowrap|(49/48)<sup>''n''</sup> ~ 25/24}}. Varying ''n'' results in different temperament families listed in the table below. It converges to [[semaphore]] as ''n'' approaches infinity. If we allow non-integer and infinite ''n'', the continuum describes the set of all [[7-limit]] temperament families supported by decimal (due to it being the unique rank-2 temperament that tempers both commas and thus tempers all combinations of them). The just value of ''n'' is approximately 1.9797965913603088..., and temperaments having ''n'' near this value will be more accurate. As this value is so close to 2, temperaments tempering out the [[2401/2400|breedsma (2401/2400)]] are unusually accurate. It is even closer to 196/99, but the equivalent comma, while tiny even for an [[unnoticeable comma]] at 0.004907{{cent}}, is unreasonably complex, with a monzo of {{monzo|-487 -97 -198 392}}.  
 
{| class="wikitable center-1"
|+ style="font-size: 105%;" | Temperaments in the continuum
|-
|-
! rowspan="2" |''n''
! rowspan="2" | ''n''
! rowspan="2" |Temperament
! rowspan="2" | Temperament
! colspan="2" |Comma
! colspan="2" | Comma
|-
|-
!Ratio
! Ratio
!Monzo
! Monzo
|-
|-
| -1
| −1
|10 & 4 & 12d
| 4 & 10 & 12d
|1225/1152
| 1225/1152
|{{monzo|-7 -2 2 2}}
| {{Monzo| -7 -2 2 2 }}
|-
|-
|0
| 0
|[[Dicot]]
| [[Dicot]] expansion
|[[25/24]]
| [[25/24]]
|{{monzo|-3 -1 2 0}}
| {{Monzo| -3 -1 2 0 }}
|-
|-
|1
| 1
|[[Jubilismic temperament|Jubilismic]]
| [[Jubilismic]]
|[[50/49]]
| [[50/49]]
|{{monzo|1 0 2 -2}}
| {{Monzo| 1 0 2 -2 }}
|-
|-
|2
| 2
|[[Breed (temperament)|Breed]]
| [[Breed (temperament)|Breed]]
|[[2401/2400]]
| [[2401/2400]]
|{{monzo|-5 -1 -2 4}}
| {{Monzo| -5 -1 -2 4 }}
|-
|-
|3
| 3
|46 & 60 & 50
| 46 & 50 & 60
|117649/115200
| 117649/115200
|{{monzo|-9 -2 -2 6}}
| {{monzo|-9 -2 -2 6}}
|-
|-
|…
| …
|…
| …
|…
| …
|…
| …
|-
|-
|∞
| ∞
|[[Semaphore]]
| [[Semaphoresmic]]
|[[49/48]]
| [[49/48]]
|{{monzo| -4 -1 0 2}}
| {{monzo| -4 -1 0 2 }}
|}
|}
{| class="wikitable center-1 center-2"
 
|+Temperaments with non-integer n
{| class="wikitable center-1"
|+ style="font-size: 105%;" | Temperaments with non-integer ''n''
|-
|-
! rowspan="2" |''n''
! rowspan="2" | ''n''
! rowspan="2" |Temperament
! rowspan="2" | Temperament
! colspan="2" |Comma
! colspan="2" | Comma
|-
|-
!Ratio
! Ratio
!Monzo
! Monzo
|-
|-
|196/99
| 196/99
|10 & 4 & 3299cd
| 4 & 10 & 3299cd
|664 digits
| 664 digits
|{{monzo|-487 -97 -198 392}}
| {{Monzo| -487 -97 -198 392 }}
|}
|}
[[Category:Equivalence continua]]
[[Category:Equivalence continua]]

Latest revision as of 07:51, 28 January 2026

This page presents a topic of primarily mathematical interest.

While it is derived from sound mathematical principles, its applications in terms of utility for actual music may be limited, highly contrived, or as yet unknown.

The semaphore–chromatic equivalence continuum is a continuum of 7-limit rank-3 temperament families which equate a number of semaphore commas (49/48) with a classic chromatic semitone (25/24). This continuum is theoretically interesting in that these are all 7-limit rank-3 temperament families supported by decimal temperament.

All temperaments in the continuum satisfy (49/48)n ~ 25/24. Varying n results in different temperament families listed in the table below. It converges to semaphore as n approaches infinity. If we allow non-integer and infinite n, the continuum describes the set of all 7-limit temperament families supported by decimal (due to it being the unique rank-2 temperament that tempers both commas and thus tempers all combinations of them). The just value of n is approximately 1.9797965913603088..., and temperaments having n near this value will be more accurate. As this value is so close to 2, temperaments tempering out the breedsma (2401/2400) are unusually accurate. It is even closer to 196/99, but the equivalent comma, while tiny even for an unnoticeable comma at 0.004907 ¢, is unreasonably complex, with a monzo of [-487 -97 -198 392.

Temperaments in the continuum
n Temperament Comma
Ratio Monzo
−1 4 & 10 & 12d 1225/1152 [-7 -2 2 2
0 Dicot expansion 25/24 [-3 -1 2 0
1 Jubilismic 50/49 [1 0 2 -2
2 Breed 2401/2400 [-5 -1 -2 4
3 46 & 50 & 60 117649/115200 [-9 -2 -2 6
Semaphoresmic 49/48 [-4 -1 0 2
Temperaments with non-integer n
n Temperament Comma
Ratio Monzo
196/99 4 & 10 & 3299cd 664 digits [-487 -97 -198 392