Tenney–Euclidean temperament measures: Difference between revisions
Wikispaces>genewardsmith **Imported revision 472438896 - Original comment: ** |
Wikispaces>genewardsmith **Imported revision 472454310 - Original comment: ** |
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<h2>IMPORTED REVISION FROM WIKISPACES</h2> | <h2>IMPORTED REVISION FROM WIKISPACES</h2> | ||
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | ||
: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2013-11-26 | : This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2013-11-26 12:28:25 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>472454310</tt>.<br> | ||
: The revision comment was: <tt></tt><br> | : The revision comment was: <tt></tt><br> | ||
The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | ||
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\displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi | \displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi | ||
[[math]] | [[math]] | ||
is an adjusted error which makes the error of a rank r temperament correspond to the errors of the edo vals which support it; so that requiring the edo val error to be less than (1 + ε)ψ for any positive ε results in an infinite set of vals supporting the temperament. ψ can be related to TE error as it appears on Graham Breed's [[http://x31eq.com/temper/|temperament finder]], which we will call | is an adjusted error which makes the error of a rank r temperament correspond to the errors of the edo vals which support it; so that requiring the edo val error to be less than (1 + ε)ψ for any positive ε results in an infinite set of vals supporting the temperament. ψ can be related to TE error as it appears on Graham Breed's [[http://x31eq.com/temper/|temperament finder]], which we will call RMS error; if G denotes the RMS error for a temperament, then | ||
[[math]] | [[math]] | ||
\displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi | \displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi | ||
[[math]] | [[math]] | ||
RMS error and ψ error both have the advantage that higher rank temperament error corresponds directly to rank one error, but the RMS normalization has the further advantage that in the rank one case, G = sin θ, where θ is the angle between J and the val in question. Multiplying by 1200 to obtain a result in cents leads to 1200 sin θ, TE error as it appears on the temperament finder pages. RMS error may also be found using the TE tuning map; if T is the tuning map, then | |||
[[math]] | [[math]] | ||
\displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}} | \displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}} = || T-J || | ||
[[math]] | [[math]] | ||
where the dot represents the ordinary dot product. If T is denominated in cents, then J should be also, so that J = <1200 1200 ... 1200|.</pre></div> | where the dot represents the ordinary dot product. If T is denominated in cents, then J should be also, so that J = <1200 1200 ... 1200|.</pre></div> | ||
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\displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi&lt;br/&gt;[[math]] | \displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi&lt;br/&gt;[[math]] | ||
--><script type="math/tex">\displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi</script><!-- ws:end:WikiTextMathRule:2 --><br /> | --><script type="math/tex">\displaystyle \psi = \sqrt{\frac{2(n-r)}{(r+1)(n-1)}} \Psi</script><!-- ws:end:WikiTextMathRule:2 --><br /> | ||
is an adjusted error which makes the error of a rank r temperament correspond to the errors of the edo vals which support it; so that requiring the edo val error to be less than (1 + ε)ψ for any positive ε results in an infinite set of vals supporting the temperament. ψ can be related to TE error as it appears on Graham Breed's <a class="wiki_link_ext" href="http://x31eq.com/temper/" rel="nofollow">temperament finder</a>, which we will call | is an adjusted error which makes the error of a rank r temperament correspond to the errors of the edo vals which support it; so that requiring the edo val error to be less than (1 + ε)ψ for any positive ε results in an infinite set of vals supporting the temperament. ψ can be related to TE error as it appears on Graham Breed's <a class="wiki_link_ext" href="http://x31eq.com/temper/" rel="nofollow">temperament finder</a>, which we will call RMS error; if G denotes the RMS error for a temperament, then<br /> | ||
<!-- ws:start:WikiTextMathRule:3: | <!-- ws:start:WikiTextMathRule:3: | ||
[[math]]&lt;br/&gt; | [[math]]&lt;br/&gt; | ||
\displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi&lt;br/&gt;[[math]] | \displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi&lt;br/&gt;[[math]] | ||
--><script type="math/tex">\displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi</script><!-- ws:end:WikiTextMathRule:3 --><br /> | --><script type="math/tex">\displaystyle G = \sqrt{\frac{n-1}{2n}} \psi = \sqrt{\frac{n-r}{(r+1)n}} \Psi</script><!-- ws:end:WikiTextMathRule:3 --><br /> | ||
RMS error and ψ error both have the advantage that higher rank temperament error corresponds directly to rank one error, but the RMS normalization has the further advantage that in the rank one case, G = sin θ, where θ is the angle between J and the val in question. Multiplying by 1200 to obtain a result in cents leads to 1200 sin θ, TE error as it appears on the temperament finder pages. RMS error may also be found using the TE tuning map; if T is the tuning map, then<br /> | |||
<!-- ws:start:WikiTextMathRule:4: | <!-- ws:start:WikiTextMathRule:4: | ||
[[math]]&lt;br/&gt; | [[math]]&lt;br/&gt; | ||
\displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}}&lt;br/&gt;[[math]] | \displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}} = || T-J ||&lt;br/&gt;[[math]] | ||
--><script type="math/tex">\displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}}</script><!-- ws:end:WikiTextMathRule:4 --><br /> | --><script type="math/tex">\displaystyle G = \sqrt{\frac{(T -J) \cdot (T - J)}{n}} = || T-J ||</script><!-- ws:end:WikiTextMathRule:4 --><br /> | ||
where the dot represents the ordinary dot product. If T is denominated in cents, then J should be also, so that J = &lt;1200 1200 ... 1200|.</body></html></pre></div> | where the dot represents the ordinary dot product. If T is denominated in cents, then J should be also, so that J = &lt;1200 1200 ... 1200|.</body></html></pre></div> | ||