247edo: Difference between revisions

BudjarnLambeth (talk | contribs)
mNo edit summary
Expand on theory; +subsets and supersets
Line 1: Line 1:
{{Infobox ET}}
{{Infobox ET}}
The '''247 equal divisions of the octave''' ('''247EDO'''), or the '''247(-tone) equal temperament''' ('''247TET''', '''247ET''') when viewed from a [[regular temperament]] perspective, is the [[EDO|equal division of the octave]] into 247 parts of 4.8583 [[cent]]s each.
{{EDO intro}}


== Theory ==
[[Prime harmonic]]s [[3/1|3]], [[5/1|5]], [[7/1|7]], and [[11/1|11]] are all about halfway between 247edo's steps, so 247edo lacks [[consistency]] to the [[5-odd-limit|5]] and higher odd limits. It is the largest numbered edo that the closest approximation to 3/2 is flatter than that of [[12edo]] (700¢, [[Compton family|compton fifth]]). Using the [[patent val]], it tempers out [[126/125]], [[243/242]] and [[1029/1024]] in the 11-limit , so it [[support]]s the ''hemivalentino'' temperament (31 & 61e).  
In 247EDO, 144 degree represents [[3/2]] (2.36¢ flat), 80 degree represents [[5/4]] (2.35¢ sharp), 199 degree represents [[7/4]] (2.02¢ flat), and 113 degree represents [[11/8]] (2.33¢ flat). 247EDO lacks consistency to the 5 and higher odd-limit. It is the largest number EDO that interval representing 3/2 is flatter than that of [[12EDO]] (700¢, [[Compton family|compton]] fifth). It tempers out [[126/125]], [[243/242]] and [[1029/1024]] in the 11-limit patent mapping, so it [[support]]s the ''hemivalentino'' temperament (31&61e).
 
As every other step of the monstrous [[494edo]], 247edo can be used in the 2.9.15.21 [[subgroup]].
 
=== Odd harmonics ===
{{Harmonics in equal|247|columns=15}}
{{Harmonics in equal|247|columns=15}}


[[Category:Equal divisions of the octave|###]] <!-- 3-digit number -->
=== Subsets and supersets ===
Since 247 factors into {{factorization|247}}, 247edo contains [[13edo]] and [[19edo]] as its subsets. 494edo, which doubles it, provides excellent correction to all the lower prime harmonics.