Prime number
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=Prime numbers in [[EDO]]s= A //prime number// is an integer (whole number) greater than one which is divisible only by itself and one. There an an infinite number of prime numbers, the first few of which are 2, 3, 5, 7, 11, 13 ... . Whether or not a number //n// is prime has important consequences for the properties of the corresponding //n//-[[edo|EDO]], especially for lower values of //n//. * If the octave is divided into a prime number of equal parts, there is //no fully symmetric chord//, such as the diminished seventh chord in [[12edo]]. * There is also (besides the scale comprising all notes of the EDO) //no absolutely uniform, octave-repeating scale//, like the wholetone scale in 12edo. * Nor is there a thing like [[http://en.wikipedia.org/wiki/Modes_of_limited_transposition|modes of limited transpostion]], as used by the composer Olivier Messiaen. * //n//-EDO does not support any rank two temperament with period a fraction of an octave; all such temperaments are //linear// temperaments. For these or similar reasons, some musicians do not like the prime EDOs (e.g. the makers of [[http://www.armodue.com/risorse.htm|Armodue]]). On the other hand, primality may be desirable if you want, for example, a wholetone scale that is //not// absolutely uniform. (In this case you might like [[19edo]], for example.) The larger //n// is, the less these points matter, since the difference between an //absolutely// uniform scale and an approximated, //nearly// uniform scale eventually become inaudible. [TODO: add more useful things about prime numbers for musicians, composers, microtonalists, xenharmonicians, ekmelicians and theorists here.] ==The first 46 Prime EDOs== Multiples of an EDO, including multiples of a prime EDO, can inherit properties from that EDO, in particular a tuning for certain intervals. A multiple however is by definition more complex; a prime EDO is always the least complex EDO divisible by that prime, and these are listed below: [[2edo|2]], [[3edo|3]], [[5edo|5]], [[7edo|7]], [[11edo|11]], [[13edo|13]], [[17edo|17]], [[19edo|19]], [[23edo|23]], [[29edo|29]], [[31edo|31]], [[37edo|37]], [[41edo|41]], [[43edo|43]], [[47edo|47]], [[53edo|53]], [[59edo|59]], [[61edo|61]], [[67edo|67]], [[71edo|71]], [[73edo|73]], [[79edo|79]], [[83edo|83]], [[89edo|89]], [[97edo|97]], [[101edo|101]], [[103edo|103]], [[107edo|107]], [[109edo|109]], [[113edo|113]], [[127edo|127]], [[131edo|131]], [[137edo|137]], [[139edo|139]], [[149edo|149]], [[151edo|151]], [[157edo|157]], [[163edo|163]], [[167edo|167]], [[173edo|173]], [[179edo|179]], [[181edo|181]], [[191edo|191]], [[193edo|193]], [[197edo|197]] & [[199edo|199]]. ==See also== * [[The Prime Harmonic Series]] * [[Monzo]] - an alternative notation for interval ratios * [[prime limit]] or [[Harmonic Limit]] ==Links== * [[http://www.arndt-bruenner.de/mathe/scripts/primzahlen.htm|Die Primzahlseite]] (German) by Arndt Brünner (helpful tools for prime factorization and ~test) * [[http://en.wikipedia.org/wiki/Prime_number|Prime number]] the Wikipedia article
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<html><head><title>prime numbers</title></head><body><!-- ws:start:WikiTextHeadingRule:0:<h1> --><h1 id="toc0"><a name="Prime numbers in EDOs"></a><!-- ws:end:WikiTextHeadingRule:0 -->Prime numbers in <a class="wiki_link" href="/EDO">EDO</a>s</h1> <br /> A <em>prime number</em> is an integer (whole number) greater than one which is divisible only by itself and one. There an an infinite number of prime numbers, the first few of which are 2, 3, 5, 7, 11, 13 ... . Whether or not a number <em>n</em> is prime has important consequences for the properties of the corresponding <em>n</em>-<a class="wiki_link" href="/edo">EDO</a>, especially for lower values of <em>n</em>.<br /> <ul><li>If the octave is divided into a prime number of equal parts, there is <em>no fully symmetric chord</em>, such as the diminished seventh chord in <a class="wiki_link" href="/12edo">12edo</a>.</li><li>There is also (besides the scale comprising all notes of the EDO) <em>no absolutely uniform, octave-repeating scale</em>, like the wholetone scale in 12edo.</li><li>Nor is there a thing like <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Modes_of_limited_transposition" rel="nofollow">modes of limited transpostion</a>, as used by the composer Olivier Messiaen.</li><li><em>n</em>-EDO does not support any rank two temperament with period a fraction of an octave; all such temperaments are <em>linear</em> temperaments.</li></ul><br /> For these or similar reasons, some musicians do not like the prime EDOs (e.g. the makers of <a class="wiki_link_ext" href="http://www.armodue.com/risorse.htm" rel="nofollow">Armodue</a>).<br /> <br /> On the other hand, primality may be desirable if you want, for example, a wholetone scale that is <em>not</em> absolutely uniform. (In this case you might like <a class="wiki_link" href="/19edo">19edo</a>, for example.)<br /> <br /> The larger <em>n</em> is, the less these points matter, since the difference between an <em>absolutely</em> uniform scale and an approximated, <em>nearly</em> uniform scale eventually become inaudible.<br /> <br /> [TODO: add more useful things about prime numbers for musicians, composers, microtonalists, xenharmonicians, ekmelicians and theorists here.]<br /> <br /> <!-- ws:start:WikiTextHeadingRule:2:<h2> --><h2 id="toc1"><a name="Prime numbers in EDOs-The first 46 Prime EDOs"></a><!-- ws:end:WikiTextHeadingRule:2 -->The first 46 Prime EDOs</h2> Multiples of an EDO, including multiples of a prime EDO, can inherit properties from that EDO, in particular a tuning for certain intervals. A multiple however is by definition more complex; a prime EDO is always the least complex EDO divisible by that prime, and these are listed below:<br /> <br /> <a class="wiki_link" href="/2edo">2</a>, <a class="wiki_link" href="/3edo">3</a>, <a class="wiki_link" href="/5edo">5</a>, <a class="wiki_link" href="/7edo">7</a>, <a class="wiki_link" href="/11edo">11</a>, <a class="wiki_link" href="/13edo">13</a>, <a class="wiki_link" href="/17edo">17</a>,<br /> <a class="wiki_link" href="/19edo">19</a>, <a class="wiki_link" href="/23edo">23</a>, <a class="wiki_link" href="/29edo">29</a>, <a class="wiki_link" href="/31edo">31</a>, <a class="wiki_link" href="/37edo">37</a>, <a class="wiki_link" href="/41edo">41</a>, <a class="wiki_link" href="/43edo">43</a>,<br /> <a class="wiki_link" href="/47edo">47</a>, <a class="wiki_link" href="/53edo">53</a>, <a class="wiki_link" href="/59edo">59</a>, <a class="wiki_link" href="/61edo">61</a>, <a class="wiki_link" href="/67edo">67</a>, <a class="wiki_link" href="/71edo">71</a>, <a class="wiki_link" href="/73edo">73</a>,<br /> <a class="wiki_link" href="/79edo">79</a>, <a class="wiki_link" href="/83edo">83</a>, <a class="wiki_link" href="/89edo">89</a>, <a class="wiki_link" href="/97edo">97</a>, <a class="wiki_link" href="/101edo">101</a>, <a class="wiki_link" href="/103edo">103</a>, <a class="wiki_link" href="/107edo">107</a>,<br /> <a class="wiki_link" href="/109edo">109</a>, <a class="wiki_link" href="/113edo">113</a>, <a class="wiki_link" href="/127edo">127</a>, <a class="wiki_link" href="/131edo">131</a>, <a class="wiki_link" href="/137edo">137</a>, <a class="wiki_link" href="/139edo">139</a>, <a class="wiki_link" href="/149edo">149</a>,<br /> <a class="wiki_link" href="/151edo">151</a>, <a class="wiki_link" href="/157edo">157</a>, <a class="wiki_link" href="/163edo">163</a>, <a class="wiki_link" href="/167edo">167</a>, <a class="wiki_link" href="/173edo">173</a>, <a class="wiki_link" href="/179edo">179</a>, <a class="wiki_link" href="/181edo">181</a>,<br /> <a class="wiki_link" href="/191edo">191</a>, <a class="wiki_link" href="/193edo">193</a>, <a class="wiki_link" href="/197edo">197</a> & <a class="wiki_link" href="/199edo">199</a>.<br /> <br /> <!-- ws:start:WikiTextHeadingRule:4:<h2> --><h2 id="toc2"><a name="Prime numbers in EDOs-See also"></a><!-- ws:end:WikiTextHeadingRule:4 -->See also</h2> <ul><li><a class="wiki_link" href="/The%20Prime%20Harmonic%20Series">The Prime Harmonic Series</a></li><li><a class="wiki_link" href="/Monzo">Monzo</a> - an alternative notation for interval ratios</li><li><a class="wiki_link" href="/prime%20limit">prime limit</a> or <a class="wiki_link" href="/Harmonic%20Limit">Harmonic Limit</a></li></ul><br /> <!-- ws:start:WikiTextHeadingRule:6:<h2> --><h2 id="toc3"><a name="Prime numbers in EDOs-Links"></a><!-- ws:end:WikiTextHeadingRule:6 -->Links</h2> <ul><li><a class="wiki_link_ext" href="http://www.arndt-bruenner.de/mathe/scripts/primzahlen.htm" rel="nofollow">Die Primzahlseite</a> (German) by Arndt Brünner (helpful tools for prime factorization and ~test)</li><li><a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Prime_number" rel="nofollow">Prime number</a> the Wikipedia article</li></ul></body></html>