7edo: Difference between revisions

<h2>IMPORTED REVISION FROM WIKISPACES</h2>

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<h4>Original Wikitext content:</h4>

Equi-heptitonic scales are used in non-western music in African cultures and it has been speculated in "Indian music:history and structure", that the Indian three-sruti interval of 165 cents is close enough to be mistaken for 171 cents. (or 1.71 semitones).

7-tet can be thought of as result of stacking seven 11/9s on top of each other, and then tempering to remove the comma 2^(-2) 3^(-14) 11^7.

Similarly, in equi-heptatonic systems the desire for harmonic sound may dictate constant adjustments of intonation away from the theoretical interval of 171 cents. One of the most impressive areas in Africa in which a pen-equidistant heptatonic scale is combined with a distinctively harmonic style based on singing in intervals of thirds plus fifths, or thirds plus fourths, is the eastern Angolan culture area. This music is heptatonic and non-modal; i.e., there is no concept of major or minor thirds as distinctive intervals. In principle all the thirds are neutral, but in practice the thirds rendered by the singers often approximate natural major thirds (386 cents), especially at points of rest. In this manner, the principles of equidistance and harmonic euphony are accommodated within one tonal-harmonic system. For the notation of such music, a seven-line stave is most appropriate, with each horizontal line representing one pitch level.

Equi-heptitonic scales are used in non-western music in African cultures and it has been speculated in &amp;quot;Indian music:history and structure&amp;quot;, that the Indian three-sruti interval of 165 cents is close enough to be mistaken for 171 cents. (or 1.71 semitones).&lt;br /&gt;

7-tet can be thought of as result of stacking seven 11/9s on top of each other, and then tempering to remove the comma 2^(-2) 3^(-14) 11^7.&lt;br /&gt;

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Similarly, in equi-heptatonic systems the desire for harmonic sound may dictate constant adjustments of intonation away from the theoretical interval of 171 cents. One of the most impressive areas in Africa in which a pen-equidistant heptatonic scale is combined with a distinctively harmonic style based on singing in intervals of thirds plus fifths, or thirds plus fourths, is the eastern Angolan culture area. This music is heptatonic and non-modal; i.e., there is no concept of major or minor thirds as distinctive intervals. In principle all the thirds are neutral, but in practice the thirds rendered by the singers often approximate natural major thirds (386 cents), especially at points of rest. In this manner, the principles of equidistance and harmonic euphony are accommodated within one tonal-harmonic system. For the notation of such music, a seven-line stave is most appropriate, with each horizontal line representing one pitch level.&lt;br /&gt;

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A Thai xylophone measured by Morton (1974) &amp;quot;varied only plus or minus 5 cents,&amp;quot; from 7-TET. A Ugandan Chopi xylophone measured by Haddon (1952) was also tuned to this system.&lt;br /&gt;

Step from seventh to octave is too large for the leading tone.&lt;br /&gt;

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