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Modmos

🔗Gene Ward Smith <gwsmith@svpal.org>

7/11/2004 1:23:08 PM

Here's some more jargon for you jargon lovers, and I know you're out
there. Suppose there is an N-note MOS for some linear temperament,
which for simplicity we can assume has period an octave. Suppose we
have an N note scale, described in terms of a set N generator steps in
our temperament, in which the graph of the scale (connecting
consonances in an odd limit of the temperament) is connected, and
which reduces modulo N to the N-note MOS. We could call such a beast a
modmos.

Modmos are interesting because the most interesting N-note scales of
our temperament will be modmos; another way of defining it is that the
scale is in the given temperament and is N-epimorphic and connected.
If the tuning of the temperament is N-et, then this simply reduces to
N-equal; but if it is close to but not identical to N-et then the
modmos will be reasonably regular in terms of evenness and step size.
One can find modmos by tempering a block or working with a relatively
prime pair of intervals (measured in terms of generator steps) among
other methods. What the best method of finding them and then assessing
them is a question worth exploring, I think.