MOS scale: Difference between revisions

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**Imported revision 3493012 - Original comment: **
Wikispaces>hstraub
**Imported revision 3493240 - 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:hstraub|hstraub]] and made on <tt>2007-03-27 11:17:43 UTC</tt>.<br>
: This revision was by author [[User:hstraub|hstraub]] and made on <tt>2007-03-27 11:30:19 UTC</tt>.<br>
: The original revision id was <tt>3493012</tt>.<br>
: The original revision id was <tt>3493240</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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a*L +b*s = n.
a*L +b*s = n.


which is a [[http://mathworld.wolfram.com/DiophantineEquation.html|linear diophantine equation]]! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.
which is a linear diophantine equation! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.


Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.
Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.
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[[PentatonicMOS|Pentatonic MOS]]
[[PentatonicMOS|Pentatonic MOS]]
[[HexatonicMOS|Hexatonic MOS]]
&lt;More follow soon&gt;</pre></div>
&lt;More follow soon&gt;</pre></div>
<h4>Original HTML content:</h4>
<h4>Original HTML content:</h4>
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a*L +b*s = n.&lt;br /&gt;
a*L +b*s = n.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
which is a &lt;a class="wiki_link_ext" href="http://mathworld.wolfram.com/DiophantineEquation.html" rel="nofollow"&gt;linear diophantine equation&lt;/a&gt;! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.&lt;br /&gt;
which is a linear diophantine equation! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.&lt;br /&gt;
Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.&lt;br /&gt;
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&lt;br /&gt;
&lt;br /&gt;
&lt;a class="wiki_link" href="/PentatonicMOS"&gt;Pentatonic MOS&lt;/a&gt;&lt;br /&gt;
&lt;a class="wiki_link" href="/PentatonicMOS"&gt;Pentatonic MOS&lt;/a&gt;&lt;br /&gt;
&lt;a class="wiki_link" href="/HexatonicMOS"&gt;Hexatonic MOS&lt;/a&gt;&lt;br /&gt;
&amp;lt;More follow soon&amp;gt;&lt;/body&gt;&lt;/html&gt;</pre></div>
&amp;lt;More follow soon&amp;gt;&lt;/body&gt;&lt;/html&gt;</pre></div>

Revision as of 11:30, 27 March 2007

IMPORTED REVISION FROM WIKISPACES

This is an imported revision from Wikispaces. The revision metadata is included below for reference:

This revision was by author hstraub and made on 2007-03-27 11:30:19 UTC.
The original revision id was 3493240.
The revision comment was:

The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.

Original Wikitext content:

=MOS scales=

An important class of scales are MOS scales (MOS "Moment of symmetry").
An MOS scale is a scale whose basic steps come in 2 different sizes. This is an interesting property because two basic scales of classical music theory have it: the diatonic scale (whole tone and semitone) and the pentatonic scale (minor third and whole tone).
For more information of the background and why it is called "moment of symmetry", see
[[http://tonalsoft.com/enc/m/mos.aspx|Joe Monzo's encyclopedia of microtonal music theory]]

==Classification of MOS==
An obvious first rough classification of MOS scales is given by the number of elements of the scale - the number of large intervals (L) and the number of small intervals (s). E.g., the diatonic scale in 12-tone equal temperament could be described as 5L 2s (5 large steps and 2 small steps).
Since numbers tend to be dry, Graham Breed has proposed a [[MOSNamingScheme|naming scheme for MOS scales]].

==MOS in equal temperaments==
In the special case of an equal temperament, more concrete things about MOS can be stated.
In an equal temparement, all intervals - and hence also the intervals L and s - are integer multiples of a smallest unit. (Example: in case of the diatonic scale in 12EDO, L would be 2 and s 1.)
If we have an arbitrary MOS scale in an n-tone equal temperament, with a steps of size L and b steps of size s, there holds

a*L +b*s = n.

which is a linear diophantine equation! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.

Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.
Not all mathematical possibilities are listed - solutions of the equation that would yield too "exotic" scale steps (too small/tto big diffference between s and L) are excluded. (The concrete restrictions applied were: a solution appears if 7/6 < L/s < 5.)

[[PentatonicMOS|Pentatonic MOS]]
[[HexatonicMOS|Hexatonic MOS]]
<More follow soon>

Original HTML content:

<html><head><title>MOSScales</title></head><body><!-- ws:start:WikiTextHeadingRule:0:&lt;h1&gt; --><h1 id="toc0"><a name="MOS scales"></a><!-- ws:end:WikiTextHeadingRule:0 -->MOS scales</h1>
<br />
An important class of scales are MOS scales (MOS &quot;Moment of symmetry&quot;).<br />
An MOS scale is a scale whose basic steps come in 2 different sizes. This is an interesting property because two basic scales of classical music theory have it: the diatonic scale (whole tone and semitone) and the pentatonic scale (minor third and whole tone).<br />
For more information of the background and why it is called &quot;moment of symmetry&quot;, see<br />
<a class="wiki_link_ext" href="http://tonalsoft.com/enc/m/mos.aspx" rel="nofollow">Joe Monzo's encyclopedia of microtonal music theory</a><br />
<br />
<!-- ws:start:WikiTextHeadingRule:2:&lt;h2&gt; --><h2 id="toc1"><a name="MOS scales-Classification of MOS"></a><!-- ws:end:WikiTextHeadingRule:2 -->Classification of MOS</h2>
An obvious first rough classification of MOS scales is given by the number of elements of the scale - the number of large intervals (L) and the number of small intervals (s). E.g., the diatonic scale in 12-tone equal temperament could be described as 5L 2s (5 large steps and 2 small steps).<br />
Since numbers tend to be dry, Graham Breed has proposed a <a class="wiki_link" href="/MOSNamingScheme">naming scheme for MOS scales</a>.<br />
<br />
<!-- ws:start:WikiTextHeadingRule:4:&lt;h2&gt; --><h2 id="toc2"><a name="MOS scales-MOS in equal temperaments"></a><!-- ws:end:WikiTextHeadingRule:4 -->MOS in equal temperaments</h2>
In the special case of an equal temperament, more concrete things about MOS can be stated.<br />
In an equal temparement, all intervals - and hence also the intervals L and s - are integer multiples of a smallest unit. (Example: in case of the diatonic scale in 12EDO, L would be 2 and s 1.)<br />
If we have an arbitrary MOS scale in an n-tone equal temperament, with a steps of size L and b steps of size s, there holds<br />
<br />
a*L +b*s = n.<br />
<br />
which is a linear diophantine equation! This means that given a, b and n, all possible MOS types can be calculated via the general solution of the corresponding linear diophantine equation.<br />
<br />
Below is a list of MOS with number of elements from 5 to 10, in equal temperaments from 5 to 36.<br />
Not all mathematical possibilities are listed - solutions of the equation that would yield too &quot;exotic&quot; scale steps (too small/tto big diffference between s and L) are excluded. (The concrete restrictions applied were: a solution appears if 7/6 &lt; L/s &lt; 5.)<br />
<br />
<a class="wiki_link" href="/PentatonicMOS">Pentatonic MOS</a><br />
<a class="wiki_link" href="/HexatonicMOS">Hexatonic MOS</a><br />
&lt;More follow soon&gt;</body></html>