Gammic family: Difference between revisions

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=== Overview to extensions ===
=== Overview to extensions ===
==== 7-limit extensions ====
Because 171 is such a strong [[7-limit]] system, it is well motivated to extend gammic to the 7-limit. This we may do by adding [[4375/4374]] to the comma list. 96 gammic generators finally reach 7, which is a long way to go compared to the 39 generator steps of [[pontiac]]. If someone wants to make the trip, a 103-note generator chain is possible.
Because 171 is such a strong [[7-limit]] system, it is well motivated to extend gammic to the 7-limit. This we may do by adding [[4375/4374]] to the comma list. 96 gammic generators finally reach 7, which is a long way to go compared to the 39 generator steps of [[pontiac]]. If someone wants to make the trip, a 103-note generator chain is possible.
==== Subgroup extensions ====
Gammic also naturally extends with the [[17/1|17th harmonic]], as is given in [[#Subgroup extensions_2|#Subgroup extensions]].


== Septimal gammic ==
== Septimal gammic ==
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== Neptune ==
== Neptune ==
A more interesting extension is to neptune, which divides an octave plus a gammic generator in half, to get a 10/7 generator. Neptune adds [[2401/2400]] to the gammic comma, and may be described as the 68&171 temperament. The generator chain goes merrily on, stacking one 10/7 over another, until after eighteen generator steps 6/5 (up nine octaves) is reached. Then in succession we get 12/7, the neutral third, 7/4 and 5/4. Two neutral thirds then gives a fifth, and these intervals with their inverses are the full set of [[7-odd-limit]] consonances. [[171edo]] makes a good tuning, and we can also choose to make any of the consonances besides 7/5 and 10/7 just, including the fifth, which gives a tuning extending [[Carlos Gamma]].  
A more interesting extension is to neptune, which divides an octave plus a gammic generator in half, to get a 10/7 generator. Neptune adds [[2401/2400]] to the gammic comma, and may be described as the {{nowrap| 68 & 171 }} temperament. The generator chain goes merrily on, stacking one 10/7 over another, until after eighteen generator steps [[6/5]] (up nine octaves) is reached. Then in succession we get [[12/7]], the neutral third, [[7/4]] and [[5/4]]. Two neutral thirds then gives a fifth, and these intervals with their inverses are the full set of [[7-odd-limit]] consonances. [[171edo]] makes a good tuning, and we can also choose to make any of the consonances besides 7/5 and 10/7 just, including the fifth, which gives a tuning extending [[Carlos Gamma]].  


Adding 385/384 or 1375/1372 to the list of commas allows for an extension to the [[11-limit]], where (7/5)<sup>3</sup> equates to 11/4.  
Adding 385/384 or 1375/1372 to the list of commas allows for an extension to the [[11-limit]], where (7/5)<sup>3</sup> equates to 11/4.  
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[[Category:Gammic family| ]] <!-- main article -->
[[Category:Temperament families]]
[[Category:Temperament families]]
[[Category:Gammic family| ]] <!-- main article -->
[[Category:Catalogs of rank-2 temperaments]]
[[Category:Rank 2]]