Blackwood

An example of Blackwood temperament in a song by Vector

Blackwood is a regular temperament primarily supported by 15edo but in technicality by any EDO with 5edo's fifth (such as 25edo or 10edo) which takes 5edo as its 2.3.7, and treats 5 as an independent generator. Its 10-note scale (LsLsLsLsLs, pentawood) is unique among scales of its complexity for making a perfect fifth available on every note of the scale, at the cost of a ~18c detuned fifth. This means that every step of the scale has either a major or a minor triad built on it. Blackwood has Zarlino as a subset, specifically tunings wherein the difference between the large and medium steps is the same size as the small step. This overlaps with Porcupine tunings of zarlino only at 15edo.

There is also a 15-note, 20-note, etc. Blackwood scale, but these are much less common than the 10-note version which will be the main version discussed here.

Name

Blackwood is named after Easley Blackwood Jr., a microtonal composer and theorist who extensively used what we now know as the Blackwood[10] scale.

The 7-limit version of Blackwood was called "Blacksmith" originally; this name is almost obsolete.

Blackwood[10] modes

Blackwood[10] has only two modes: major (LsLsLsLsLs) and minor (sLsLsLsLsL). The unilatus, fourth, fifth, and antilatus, under 10-form classification, are always perfect. The second, third, tritone, sixth, and seventh are all major in the major scale, and all minor in the minor scale.

Blackwood[10] in 15edo

Mode	Step 0	Step 1	Step 2	Step 3	Step 4	Step 5	Step 6	Step 7	Step 8	Step 9	Step 10
Major	0c	160c	240c	400c	480c	640c	720c	880c	960c	1120c	1200c
Minor	0c	80c	240c	320c	480c	560c	720c	800c	960c	1040c	1200c