Description:
Returns a predicate, intended for use with FILTER-CHORDLIST, to test
if particular interval classes in a chord are voiced according to the
criteria specified in VSPEC-PAIRS, which is a list of pairs (INTS LIMS).
Each INTS is a list of undirected pitch intervals drawn from a single
mod-N interval class, and the absolute value of the corresponding LIM,
a positive (negative) number between 0 and 1 (-1), determines a lower
(upper) bound on the ratio J:K, where K is the multiplicity of occurrence
of the interval class represented in INTS, and J is the combined
multiplicity of occurrence of the undirected pitch intervals in INTS.
EXAMPLES (with N = 12)
- with VOICING-PAIRS = (((10 12) 3/4)), returns a test to see if at
least 3/4 of the instances of interval class 2 in a chord are voiced
as pitch intervals 10 or 22.
- with VOICING-PAIRS = (((1) 1/6) ((1) -1/2)), returns a test to see
if at least 1/6, but at most 1/2, of the instances of interval class 1
in a chord are voiced as pitch interval 1.
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