Ed5/2
Ed5/2 means Division of the classic major tenth (5/2) into n equal parts.
Properties
Division of 5/2 into equal parts can be conceived of as to directly use this interval as an equivalence, or not. The question of equivalence has not even been posed yet. The utility of 5:2, (or another tenth) as a base though, is apparent by being used at the base of so much modern tonal harmony. Many, though not all, of these scales have a perceptually important pseudo (false) octave, with various degrees of accuracy.
Incidentally, one way to treat 5/2 as an equivalence is the use of the 4:6:7:(10) chord as the fundamental complete sonority in a very similar way to the 4:5:6:(8) chord in meantone. Whereas in meantone it takes four 3/2 to get to 5/1, here it takes four 7/4 to get to 75/8 = 3/2 * (5/2)2 (tempering out the comma 2401/2400). So, doing this yields 2, 3, 5, 8, 13, and 18 note MOS. While the notes are rather farther apart, the scheme is uncannily similar to meantone.
Individual pages for ED5/2s
- 9 - Ninth root of 5/2 (9edX)
- 16 - 16th root of 5/2 (16edX)
- 18 - 18th root of 5/2
- 25 - 25th root of 5/2
- 45 - 45th root of 5/2