Musical sequence
Jud McCranie
j.mccranie at adelphia.net
Wed Jan 18 19:46:40 CET 2006
At 01:40 PM 1/18/2006, David Wilson wrote:
>In general music theory, we hold to the concept of an octave,
>specifically, that if a musical scale includes a tone of frequency f, it
>also includes a tone of frequency 2f.
>
>What if we abandon the notion of octave, but keep the idea of equally
>spaced tones, so that our scale can be described by base tone frequency b
>and a ratio r between adjacent tones on the scale.
>
>Is there a measure of goodness of r that would rate r = 2^(1/12) high?
>Presumably this rating would be based on the closeness of tone ratios to
>simple rationals which represent pleasing harmonies. Given this rating,
>what would be the best r? If we return to octave-based scales, could be
>construct a sequence of t with increasingly better ratings of 2^(1/t),
>which would represent increasingly good choices for number of tones in an
>octave?
I looked at this sometime ago. The important thing about 12 equally-spaced
tones is that r^4 is close to 5/4, r^5 is close to 4/3, and r^7 is close to
3/2, r is the 12-th root of 2, as above. The next values that come close
to these important values are when there are 43 and 53 equally-spaced tones
between frequencies f and 2f, IIRC.
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