Musical Idea 20: Moments of Ambiguity
02.15.2014 § Leave a comment
There are several methods of generating and retroactively classifying tuning systems. Occasionally a tuning can be defined using more than one different method, that is, that you can plug variables into two totally different formulas but get the same final resultant set of numbers (pitches). At these times, what I will call “moments of ambiguity”, it may be fun to jump ship from one method to another. This jumping ship is only meaningful, though, if the listener had been made aware of which method had been being used to articulate the tuning before the jump, and can ascertain the new method as distinct.
Since the resultant pitches are by definition the same at these moments of ambiguity, harmony cannot be used for this purpose. What we’re really talking about is a cousin of tonal movement and stretching, but a more advanced one: rather than simply sliding intervals around or expanding and contracting them proportionally, we are animating turning knobs on inputs to xenharmonic parameters.
The primary ones I am aware of currently are:
- Hyper-MoS, or moment of symmetry scales (cradles, chromas), which includes all EDOs
- CPS, Combination Product Sets
- poly-polychord tunings (combining sets of the same chord offset)
Happy to hear about any others!
In addition to playing with knobs on the generating parameters, you can also sneak ghost pitches in and out to help out. Especially if two tunings aren’t exactly the same because they’re almost the same but one has an extra note or two, you can just fade those notes out, or lower the probability of them appearing until it hits zero.