Overtone scale: Difference between revisions
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== Primodality== | == Primodality== | ||
[[Zhea Erose]] has considered over-p scales and chords where p is a prime, which she calls '''primodal scales'''. ''Primodality''' is an approach to JI designed to emphasize the identity of the "tonic" as the pth harmonic. Name- and notation-wise, scales and structures | [[Zhea Erose]] has considered over-p scales and chords where p is a prime, which she calls '''primodal scales'''. ''Primodality''' is an approach to JI designed to emphasize the identity of the "tonic" as the pth harmonic. Name- and notation-wise, scales and structures having the identity of the prime p as the tonic are collectively called a '''prime family''', and can be denoted simply by ''/p''. Zhea also uses various adjectives for specific primodalities, such as ''septimal, undecimal, tridecimal, septendecimal, novem(decimal)'' for /7, /11, /13, /17, /19, which are not to be confused with the use of these adjectives to denote prime limits. | ||
Most importantly, primodality sees any overtone as valuable on its own, rather than relative to some fundamental. Taking a specific overtone as a tonic we can get its particular scales and colors | Most importantly, primodality sees any overtone as valuable on its own, rather than relative to some fundamental. Taking a specific overtone as a tonic we can get its particular scales and colors and even versions of "non-xenharmonic" scales, even when the corresponding fundamental is too low to be audible. In particular, primodality discards the concept of [[harmonic limit]], which Zhea considers an artificial way to look at JI harmony. Zhea argues that prime family (set of intervals over a small multiple of p) is a more natural way to categorize intervals; intervals from the same prime family (intervals with a common denominator for example, all /2, all /11 or all /13) tend to blend better together. For example, it is preferable to add 21/16 to 4:5:6:7, rather than 4/3. | ||
To construct a primodal scale, we fix a prime p to be the denominator and take intervals of the form n/p, where n ≥ p. Zhea often takes n to range over a certain "lineal segment" (a segment of the harmonic series spanning an octave starting from mp where m is a positive integer) or a subset thereof. This corresponds to taking Mode mp of the harmonic series. For example, if we use p = 13 and take all n between 13 and 26 (inclusive), this would result in the scale 13:14:15:16:17:18:19:20:21:22:23:24:25:26. We may add a 3/2 to the scale root, which corresponds to adding 3p/p. (3/2 is a natural "halfway point" for harmonic scales, since if N is even, Mode N has a 3/2 as its N/2-th note.) Zhea considers the intervals in the first octave over p of the harmonic series to be the most "natural" intervals in p-primodality. | To construct a primodal scale, we fix a prime p to be the denominator and take intervals of the form n/p, where n ≥ p. Zhea often takes n to range over a certain "lineal segment" (a segment of the harmonic series spanning an octave starting from mp where m is a positive integer) or a subset thereof. This corresponds to taking Mode mp of the harmonic series. For example, if we use p = 13 and take all n between 13 and 26 (inclusive), this would result in the scale 13:14:15:16:17:18:19:20:21:22:23:24:25:26. We may add a 3/2 to the scale root, which corresponds to adding 3p/p. (3/2 is a natural "halfway point" for harmonic scales, since if N is even, Mode N has a 3/2 as its N/2-th note.) Zhea considers the intervals in the first octave over p of the harmonic series to be the most "natural" intervals in p-primodality. |