8/7: Difference between revisions

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<h2>IMPORTED REVISION FROM WIKISPACES</h2>
{{Infobox Interval
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br>
| Name = septimal whole tone, supermajor second, septimal major second, septimal supermajor second
: This revision was by author [[User:k9assassin|k9assassin]] and made on <tt>2015-03-24 20:43:46 UTC</tt>.<br>
| Color name = r2, ru 2nd
: The original revision id was <tt>545214766</tt>.<br>
| Sound = jid_8_7_pluck_adu_dr220.mp3
: 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>
{{Wikipedia|Septimal whole tone}}
<h4>Original Wikitext content:</h4>
<div style="width:100%; max-height:400pt; overflow:auto; background-color:#f8f9fa; border: 1px solid #eaecf0; padding:0em"><pre style="margin:0px;border:none;background:none;word-wrap:break-word;white-space: pre-wrap ! important" class="old-revision-html">[[image:glyph 8 7.png width="122" height="111" caption="JI glyph for 8/7"]]


**8/7**
In [[just intonation]], 8/7 is the '''septimal major second''', or '''septimal supermajor second''', of approximately 231.2{{cent}}. Although it falls between the familiar major second and minor third of [[12edo]], most people think of it more like a wide second than a narrow third. It can be found between the 7th and 8th [[harmonic]]s and is thus a [[superparticular]] ratio. In [[7-limit]] JI and higher, it is treated as a consonance, particularly in the context of a chord such as 4:5:6:7:8, where it appears between the harmonic seventh ([[7/4]]) and octave. It differs from the Pythagorean major second of [[9/8]] by [[64/63]], a microtone of about 27.3{{cent}}. It is close in size to 5edo's 240{{c}} step.
|3 0 0 -1&gt;
231,17409 cents
[[media type="file" key="jid_8_7_pluck_adu_dr220.mp3" width="240" height="20"]] [[file:xenharmonic/jid_8_7_pluck_adu_dr220.mp3|sound sample]]


In [[Just Intonation]], 8/7 is the "septimal supermajor second" of approximately 231.2¢. Although it falls between the familiar major second and minor third of [[12edo]], it generally sounds more like a wide second than a narrow third. It can be found between the 7th and 8th overtones in the harmonic series and is thus a [[superparticular]] ratio. In [[7-limit]] JI and higher, it is treated as a consonance, particularly in the context of a chord such as 4:5:6:7:8, where it appears between the harmonic seventh ([[7_4|7/4]]) and octave. It differs from the Pythagorean major second of [[9_8|9/8]] by [[64_63|64/63]], a microtone of about 27.3¢.
A stack of three supermajor seconds is close to a perfect fifth ([[3/2]]). The difference is [[1029/1024]] (about 8.4{{c}}), which is tempered out in [[slendric]] systems like [[31edo]].
== Approximation ==
{{Interval edo approximation|8/7}}
== See also ==
* [[7/4]] – its [[octave complement]]
* [[21/16]] – its [[fifth complement]]
* [[7/6]] – its [[fourth complement]]
* [[Gallery of just intervals]]


See the Wikipedia article for [[http://en.wikipedia.org/wiki/Septimal_whole_tone|Septimal whole tone]].
[[Category:Second]]
See also: [[Gallery of Just Intervals]]</pre></div>
[[Category:Supermajor second]]
<h4>Original HTML content:</h4>
[[Category:Over-7 intervals]]
<div style="width:100%; max-height:400pt; overflow:auto; background-color:#f8f9fa; border: 1px solid #eaecf0; padding:0em"><pre style="margin:0px;border:none;background:none;word-wrap:break-word;width:200%;white-space: pre-wrap ! important" class="old-revision-html">&lt;html&gt;&lt;head&gt;&lt;title&gt;8_7&lt;/title&gt;&lt;/head&gt;&lt;body&gt;&lt;!-- ws:start:WikiTextLocalImageRule:1:&amp;lt;img src=&amp;quot;/file/view/glyph%208%207.png/545214450/122x111/glyph%208%207.png&amp;quot; alt=&amp;quot;JI glyph for 8/7&amp;quot; title=&amp;quot;JI glyph for 8/7&amp;quot; style=&amp;quot;height: 111px; width: 122px;&amp;quot; /&amp;gt; --&gt;&lt;table class="captionBox"&gt;&lt;tr&gt;&lt;td class="captionedImage"&gt;&lt;img src="/file/view/glyph%208%207.png/545214450/122x111/glyph%208%207.png" alt="glyph 8 7.png" title="glyph 8 7.png" style="height: 111px; width: 122px;" /&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td class="imageCaption"&gt;JI glyph for 8/7&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;!-- ws:end:WikiTextLocalImageRule:1 --&gt;&lt;br /&gt;
&lt;br /&gt;
&lt;strong&gt;8/7&lt;/strong&gt;&lt;br /&gt;
|3 0 0 -1&amp;gt;&lt;br /&gt;
231,17409 cents&lt;br /&gt;
&lt;!-- ws:start:WikiTextMediaRule:0:&amp;lt;img src=&amp;quot;http://www.wikispaces.com/site/embedthumbnail/file-audio/jid_8_7_pluck_adu_dr220.mp3?h=20&amp;amp;w=240&amp;quot; class=&amp;quot;WikiMedia WikiMediaFile&amp;quot; id=&amp;quot;wikitext@@media@@type=&amp;amp;quot;file&amp;amp;quot; key=&amp;amp;quot;jid_8_7_pluck_adu_dr220.mp3&amp;amp;quot; width=&amp;amp;quot;240&amp;amp;quot; height=&amp;amp;quot;20&amp;amp;quot;&amp;quot; title=&amp;quot;Local Media File&amp;quot;height=&amp;quot;20&amp;quot; width=&amp;quot;240&amp;quot;/&amp;gt; --&gt;&lt;embed src="/s/mediaplayer.swf" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" quality="high" width="240" height="20" wmode="transparent" flashvars="file=http%253A%252F%252Fxenharmonic.wikispaces.com%252Ffile%252Fview%252Fjid_8_7_pluck_adu_dr220.mp3?file_extension=mp3&amp;autostart=false&amp;repeat=false&amp;showdigits=true&amp;showfsbutton=false&amp;width=240&amp;height=20"&gt;&lt;/embed&gt;&lt;!-- ws:end:WikiTextMediaRule:0 --&gt; &lt;a href="http://xenharmonic.wikispaces.com/file/view/jid_8_7_pluck_adu_dr220.mp3/513184238/jid_8_7_pluck_adu_dr220.mp3" onclick="ws.common.trackFileLink('http://xenharmonic.wikispaces.com/file/view/jid_8_7_pluck_adu_dr220.mp3/513184238/jid_8_7_pluck_adu_dr220.mp3');"&gt;sound sample&lt;/a&gt;&lt;br /&gt;
&lt;br /&gt;
In &lt;a class="wiki_link" href="/Just%20Intonation"&gt;Just Intonation&lt;/a&gt;, 8/7 is the &amp;quot;septimal supermajor second&amp;quot; of approximately 231.2¢. Although it falls between the familiar major second and minor third of &lt;a class="wiki_link" href="/12edo"&gt;12edo&lt;/a&gt;, it generally sounds more like a wide second than a narrow third. It can be found between the 7th and 8th overtones in the harmonic series and is thus a &lt;a class="wiki_link" href="/superparticular"&gt;superparticular&lt;/a&gt; ratio. In &lt;a class="wiki_link" href="/7-limit"&gt;7-limit&lt;/a&gt; JI and higher, it is treated as a consonance, particularly in the context of a chord such as 4:5:6:7:8, where it appears between the harmonic seventh (&lt;a class="wiki_link" href="/7_4"&gt;7/4&lt;/a&gt;) and octave. It differs from the Pythagorean major second of &lt;a class="wiki_link" href="/9_8"&gt;9/8&lt;/a&gt; by &lt;a class="wiki_link" href="/64_63"&gt;64/63&lt;/a&gt;, a microtone of about 27.3¢.&lt;br /&gt;
&lt;br /&gt;
See the Wikipedia article for &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Septimal_whole_tone" rel="nofollow"&gt;Septimal whole tone&lt;/a&gt;.&lt;br /&gt;
See also: &lt;a class="wiki_link" href="/Gallery%20of%20Just%20Intervals"&gt;Gallery of Just Intervals&lt;/a&gt;&lt;/body&gt;&lt;/html&gt;</pre></div>

Latest revision as of 16:02, 11 April 2026

Interval information
Ratio 8/7
Factorization 23 × 7-1
Monzo [3 0 0 -1
Size in cents 231.1741¢
Names septimal whole tone,
supermajor second,
septimal major second,
septimal supermajor second
Color name r2, ru 2nd
FJS name [math]\displaystyle{ \text{M2}_{7} }[/math]
Special properties superparticular,
reduced,
reduced subharmonic
Tenney norm (log2 nd) 5.80735
Weil norm (log2 max(n, d)) 6
Wilson norm (sopfr(nd)) 13

[sound info]
Open this interval in xen-calc
English Wikipedia has an article on:

In just intonation, 8/7 is the septimal major second, or septimal supermajor second, of approximately 231.2 ¢. Although it falls between the familiar major second and minor third of 12edo, most people think of it more like a wide second than a narrow third. It can be found between the 7th and 8th harmonics and is thus a superparticular ratio. In 7-limit JI and higher, it is treated as a consonance, particularly in the context of a chord such as 4:5:6:7:8, where it appears between the harmonic seventh (7/4) and octave. It differs from the Pythagorean major second of 9/8 by 64/63, a microtone of about 27.3 ¢. It is close in size to 5edo's 240 ¢ step.

A stack of three supermajor seconds is close to a perfect fifth (3/2). The difference is 1029/1024 (about 8.4 ¢), which is tempered out in slendric systems like 31edo.

Approximation

Edo approximations for 8/7 (231.17 ¢)
≤ 80edo, relative error ≤ 10%
Edo Step size Cents (¢) Absolute error (¢) Relative error (%)
5 1\5 240.00 +8.83 +3.68
10 2\10 240.00 +8.83 +7.35
16 3\16 225.00 -6.17 -8.23
21 4\21 228.57 -2.60 -4.55
26 5\26 230.77 -0.40 -0.88
31 6\31 232.26 +1.08 +2.80
36 7\36 233.33 +2.16 +6.48
42 8\42 228.57 -2.60 -9.11
47 9\47 229.79 -1.39 -5.43
52 10\52 230.77 -0.40 -1.75
57 11\57 231.58 +0.40 +1.92
62 12\62 232.26 +1.08 +5.60
67 13\67 232.84 +1.66 +9.28
68 13\68 229.41 -1.76 -9.99
73 14\73 230.14 -1.04 -6.31
78 15\78 230.77 -0.40 -2.63

See also