Diamond function: Difference between revisions
Wikispaces>genewardsmith **Imported revision 243027989 - Original comment: ** |
Wikispaces>genewardsmith **Imported revision 243257651 - Original comment: ** |
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: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2011-07- | : This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2011-07-28 12:33:57 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>243257651</tt>.<br> | ||
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=Definition= | =Definition= | ||
Given a collection of notes S, the //diamond// of S, diamond(S), is the set of intervals between those notes, taking the intervals in direct and inverted form, reduced to an octave. For instance, given the notes {1, 3, 5}, diamond({1, 3, 5}) is {1, 6/5, 5/4, 4/3, 3/2, 8/5, 5/3}). The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers, but it applies to any collection; for instance diamond({0, 400, 700}) where the notes are expressed in cents, is {0, 300, 400, 500, 700, 800, 900}. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the "chord of nature", or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a "chord of nature", contain this interval. | |||
=Creating scales= | =Creating scales= | ||
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Given a collection of notes S, the <em>diamond</em> of S, diamond(S), is the set of intervals between those notes, taking the intervals in direct and inverted form, reduced to an octave. For instance, given the notes {1, 3, 5}, diamond({1, 3, 5}) is {1, 6/5, 5/4, 4/3, 3/2, 8/5, 5/3}). The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers, but it applies to any collection; for instance diamond({0, 400, 700}) where the notes are expressed in cents, is {0, 300, 400, 500, 700, 800, 900}. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the &quot;chord of nature&quot;, or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a &quot;chord of nature&quot;, contain this interval. <br /> | |||
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