Eagle 53
Eagle 53 is a 12-tone tempered scale invented by John O'Sullivan.
Conception
O'Sullivan designed Eagle 53 to meet the following criteria:
- Every note between 1/1 and 2/1, when paired with both 1/1 and 2/1 must make a high strength or medium strength melodic interval. ("Strong" according to the criteria described in Eagle 53 Article (2017)).
- The tuning must not have more than 12 notes per octave, so as to fit comfortably on small stringed instruments like ukeleles.
- There must be at least one good chord on each of the twelve notes. ("Good" according to the criteria described in Eagle 53 Article (2017)).
- These good chords must be playable on a fretted instrument such as a guitar.
The overall aim was to improve upon and replace 12edo, by making 12edo's consonances even more in-tune, at least in the most important keys, while also making available new exotic consonances and melodies which 12edo lacks.
Though it used a completely different methodology than a well temperament, the philosophy behind Eagle 53 was similar to one. It is not a well temperament, but it achieves many similar aims to one.
Relationship to other scales
Eagle 53 is a subset of 53edo.
Eagle 53's just version is identical to that of Euler's Genus Diatonico-chromaticum and Ellis' Duodene, except that those used 45/32 instead of 7/5.
This similarity is by coincidence and may simply speak to the fact that this is a useful and relatively simple scale that theorists are likely to land upon over and over, much like 2L 3s or like 53edo itself.
Scala file
! eagle53.scl ! Eagle 53, John O'Sullivan, key of E 12 ! 113.2 203.8 317.0 384.9 498.1 588.7 701.9 815.1 883.0 1018.9 1086.8 1200.0
Detempering
! eagleJI.scl ! Eagle 53 detempering, John O'Sullivan, key of E 12 ! 16/15 9/8 6/5 5/4 4/3 7/5 3/2 8/5 5/3 9/5 5/8 2/1
Music
- Taking Flight - Xotla (2019)
Further reading
- Eagle 53 Article - John O'Sullivan (2017)
- Eagle Tuning Facebook group
- johnsmusic7.com: O'Sullivan's website. Contains further material on Eagle 53 among other topics.