Dinner party rules
The Dinner Party Rules are a set of rules first compiled by "Quartertone Harmony"[1], a YouTuber who had been exploring and experimenting with 24edo for some time. The basic three rules are as follows...
- Every chord must be comprised of a chain of friends in which each note is a friend to every other note
- No note can have an enemy
- No crowding
In addition to these, Quartertone Harmony's original list had a fourth rule about not using the piano for chords, though this rule is questionable, and so is not included here. As for the three rules that are retained in this article, once these are taken into consideration, finding usable chords and chord progressions in 24edo is considerably easier. However, each of these rules contains terms that require explanation- especially for purposes of generalizing these rules to other EDOs.
Friend
A friend here is defined as a note separated from the starting note by either a close approximation of an LCJI interval, or else, a close approximation of a delta rational interval, without being too close to one another in acoustic proximity. In 24edo, examples of these intervals are a major third, a minor third, a neutral third, an inframinor third, an ultramajor second, and, of course, the perfect fourth and perfect fifth.
Enemy
An enemy is defined here as a note separated from the starting note by an interval that causes intense discordance, or else, does not easily connect the two notes through LCJI or through delta rational relationships. In 24edo, examples of these intervals are an ultraprime, an inframinor second, an infraoctave, and an ultramajor seventh, and, in the majority of cases, an ultramajor third, an inframinor sixth, a paraminor fourth and a paramajor fifth also make this list in the majority of cases.
Crowding
The phenomenon of crowding is a major source of dissonance, specifically, it results when an interval separating two notes is either too small, or, too close to the octave-reduplication of the starting note. In 24edo, this is caused by intervals smaller than or equal to a major second relative to the unison or octave.