8edt: Difference between revisions

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{{Infobox ET}}
{{Infobox ET}}


As the double of [[4edt|4edt]], harmonically, it is analogous to 10edo in that the harmonic chain is doubled. However, doing so does not make it a schismatic<!--?!--> temperament like 10edo, because the full 3:5:7 triad is already present in 4edt. In any case, as a multiple of 4edt, I will say it is the widest variety of "Black-Extraterrestrial-Tree" temperament.
'''8 equal divisions of the tritave''' ('''8edt''') is the [[nonoctave]] [[tuning system]] derived by dividing the [[tritave]] (3/1) into 13 equal steps of 237.744 [[cent]]s each, or the eighth root of 3. It is best known as the equal-tempered version of the [[Bohlen-Pierce]] scale. As the double of [[4edt|4edt]], harmonically, it is the analog of [[10edo]] for [[4L 5s (3/1-equivalent)|Lambda]]-based systems. However, the full 3:5:7 triad is already present in 4edt which is unlike the situation in 10edo where 4:5:6 gains a new better approximation than the sus4 triad in 5edo.  


What it does introduce are flat pseudooctaves and sharp 3:2's, making it related to 5edo melodically.
What it does introduce are flat pseudooctaves and sharp 3:2's, making it related to 5edo melodically.

Revision as of 23:33, 26 February 2024

← 7edt 8edt 9edt →
Prime factorization 23
Step size 237.744 ¢ 
Octave 5\8edt (1188.72 ¢)
(convergent)
Consistency limit 10
Distinct consistency limit 4

8 equal divisions of the tritave (8edt) is the nonoctave tuning system derived by dividing the tritave (3/1) into 13 equal steps of 237.744 cents each, or the eighth root of 3. It is best known as the equal-tempered version of the Bohlen-Pierce scale. As the double of 4edt, harmonically, it is the analog of 10edo for Lambda-based systems. However, the full 3:5:7 triad is already present in 4edt which is unlike the situation in 10edo where 4:5:6 gains a new better approximation than the sus4 triad in 5edo.

What it does introduce are flat pseudooctaves and sharp 3:2's, making it related to 5edo melodically.

0: 1/1 0.000 unison, perfect prime

1: 237.744 cents 237.744

2: 475.489 cents 4/3

3: 713.233 cents 713.233

4: 950.978 cents 5/3

5: 1188.722 cents 1188.722

6: 1426.466 cents 1426.466

7: 1664.211 cents 1664.211

8: 3/1 1901.955 perfect 12th

Prime harmonics

Approximation of prime harmonics in 8edt
Harmonic 2 3 5 7 11 13 17 19 23 29 31
Error Absolute (¢) -11 +0 +67 -40 -110 +77 +88 -105 +40 +114 -1
Relative (%) -4.7 +0.0 +28.0 -17.0 -46.1 +32.2 +36.9 -44.1 +16.8 +48.0 -0.6
Steps
(reduced)
5
(5)
8
(0)
12
(4)
14
(6)
17
(1)
19
(3)
21
(5)
21
(5)
23
(7)
25
(1)
25
(1)