User:CompactStar/EDO impressions
Disclaimer: Don't expect my opinions to be very informed, I am not a microtonal composer.
1edo: Nothing much to say for this one. Percussion needs to take the center stage in any 1edo music. If you want to use an equal temperament with very large step sizes, I recommend a nonoctave one such as 1edf (they have far more diversity).
2edo: There is the contrast between the 2 notes, but with nothing else, it barely amounts to anything.
3edo: Has a somewhat higher level of practicality than the other ultra-small 12edo subsets, with a mild consonance (the major third) and mild dissonance (minor sixth) available. The major third can be used as a dyad here. But it's still very difficult to avoid from sounding stale.
4edo: 3edo but minor, essentially. I'm unsure if it can be called any better than 3edo, being a downgrade in terms of consonance, although there are slightly more options for melody.
5edo: We have reached the actual EDOs. Very constrained, of course, but that has some advantages. Almost all combinations of notes sound satisfactory so it is ideal for "randomly-generated" music. 1\5 is the only interval which may be reasonably considered a "third", so it is almost an exclusively minor scale, but not in a way which gets exhausted very quickly like 4edo.
6edo: By far the most popular of the 12edo subsets, it has a very directionless sound unless the type of brute-force contrast from 3edo is applied. It works well for certain genres like atonal music, but other than that it's just mediocre to me. 2-4edo, as restrictive and dissonant as they are, at least have their small size as a feature. But 6edo has the same type of dissonance while you can get a much better deal for less tones (5edo).
7edo: Interesting but I do think I prefer 5edo. Equalization of many different scales, but most importantly to listeners accustomed to 12edo, diatonic. It ends up having a definitely xenharmonic but washed-out and slightly directionless sound. I would rather use a quasi-equal heptatonic scale like 33edo's near-equalized diatonic or 3L 4s neutral third scale, they are are similar in sound but more versatile and also can be expanded if needed.
8edo: This is an EDO system that is known for its dissonance, which is true but probably not to the extent to justify its reputation. You can in fact use tertian hermony here, but it will not be very "rooted"–the "minor" triad [0 2 5] can, in certain contexts, like a major triad with the third in the bass, and vice versa for the "major" triad [0 3 5]. The 5\8 interval will only be a mild dissonance unless you are using a timbre in which both the second and third harmonics have a strong presence.