Delta-rational chord: Difference between revisions

Inthar (talk | contribs)
Tags: Mobile edit Mobile web edit
Inthar (talk | contribs)
Tags: Mobile edit Mobile web edit
Line 13: Line 13:
For example, a chord with a +1+2+1 delta signature is ''a'':(''a''+1):(''a''+3):(''a''+4) for some possibly irrational ''a''.
For example, a chord with a +1+2+1 delta signature is ''a'':(''a''+1):(''a''+3):(''a''+4) for some possibly irrational ''a''.


Dyads with no rational relationship (or no obvious one) are often indicated with +?.
Dyads with no rational relationship (or no obvious one) are often indicated with +?. For example, saying that a tetrad is "+1 +? +1" means the first two notes and the last two notes have almost equal frequency difference (thus the ratio between the differences is 1/1), but the middle two notes are not in any simple relationship with the two outer dyads. The example 13edo chord is approximately +1 +? +1. Note that this notation only considers dyads between successive notes, what we call ''(frequency) deltas''.
 
For example, saying that a tetrad is "+1 +? +1" means the first two notes and the last two notes have almost equal frequency difference (thus the ratio between the differences is 1/1), but the middle two notes are not in any simple relationship with the two outer dyads. The example 13edo chord is approximately +1 +? +1. Note that this notation only considers dyads between successive notes, what we call ''(frequency) deltas''.


If you have some sets of deltas related to each other but not to other sets of increments, you could write the related sets with variables a, b, c or use one fewer letter by writing one set with positive integers without variables: an +a +b +a +b chord can also be written +1 +a +1 +a.
If you have some sets of deltas related to each other but not to other sets of increments, you could write the related sets with variables a, b, c or use one fewer letter by writing one set with positive integers without variables: an +a +b +a +b chord can also be written +1 +a +1 +a.