Easy Scales by Interpolating between Harmonic Series: Difference between revisions
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A very easy way to construct a [[scale]] that's instantly recognizable, even without repeated listening/priming in the absence of listening the music in [[12EDO]], is to interpolate between [[harmonic series]]. | |||
I'm using the notation <<harmonic series numbers from the root>> to denote what harmonic series certain scales contain. If this seems unclear or conflicts with an existing notation, please let me know. | |||
Some of the most prominent scales in existence can be very quickly derived from | '''Some of the most prominent scales in existence can be very quickly derived from just a few interlocked/interpolated harmonic series.''' | ||
Take, for example, the diatonic major scale in 12EDO, where notes are approximately equal to | |||
{| class="wikitable" | |||
|- | |||
|+ C major diatonic in 12EDO <<8-9-12>> scale | |||
|- | |||
| C | |||
| D | |||
| E | |||
| F | |||
| G | |||
| A | |||
| B | |||
|- | |||
| 1/1 | |||
| 9/8 or 10/9 | |||
| 5/4 | |||
| 4/3 | |||
| 3/2 | |||
| 5/3 | |||
| 15/8 or 17/9 | |||
|} | |||
This can be derived from the following harmonic series | |||
</ | '''(x/9)''' - 1/1, 10/9, 12/9 (4/3), 15/9 (5/3), 17/9 | ||
which is the same as the notes C D F A B and contains the '''subdominant major chord F A C''' | |||
'''(x/8)''' - 1/1,9/8,10/8 (5/4), 12/8 (3/2), 15/8 | |||
which is the same as the notes C D E G B and contains the '''tonic major chord C E G''' along with the '''dominant major chord G B D''' | |||
'''(x/12) -''' 1/1 5/4 4/3 3/2 5/3 | |||
the same as the notes C E F G A. | |||
The '''x/12 and x/9''' harmonic series become particularly stressed in the '''([[Maqam]]) Rast''', also known as the '''"Blues" scale''', of | |||
{| class="wikitable" | |||
|- | |||
|+ Maqam Rast <<9-12>> scale | |||
|- | |||
| C | |||
| D | |||
| D#-E | |||
| F | |||
| G | |||
| A | |||
| A#-B | |||
|- | |||
| 1/1 | |||
| 9/8 or 10/9 | |||
| '''11/9''' | |||
| 4/3 | |||
| 3/2 | |||
| 5/3 or 27/16 | |||
| '''11/6''' | |||
|} | |||
Here the x/9 series uses the "blue tone" of 11/9 and grows into | |||
'''(x/9)''' - 1/1 10/9 '''11/9''' 12/9 15/9 17/9 | |||
Meanwhile the addition of the "blue tone" of 11/6 and removal of 5/4 changes the x/12 series to | |||
'''(x/12)''' - 1/1 4/3 3/2 5/3 '''11/6''' | |||
And the removal of the 5/4 and 15/8 shrinks the x/8 series into | |||
'''(x/8) -''' 1/1 9/8 3/2 | |||
If you don't like the small/compromised x/8 series, you can modify that scale by deleting the 11/9 and adding back the 5/4 and removing the 11/9 to make the scale more balanced between the size of the different series e.g. | |||
(x/8) - 1/1 9/8 5/4 3/2 | |||
and | |||
(x/9) - 1/1 10/9 4/3 5/3 17/9 | |||
'''But why limit yourself to/by x/8, x/9, and x/12 harmonic extensions of the root?''' | |||
----- | |||
'''Part 2- Attempting to create scales from scratch given harmonic series segments from a root tone''' | |||
A common pattern in the above scales is use of and interpolation between the x/9 and x/12 harmonic series | |||
It turns out the x/7 harmonic series has many notes in common with or close to the x/8, x/9, and x/12 harmonic series. | |||
We can take advantage of this to construct a more advanced scale in order the create the series | |||
'''(x/7)''' = 7:9:11:12:13 (AKA 1/1 9/7 11/7 12/7 13/7) | |||
'''(x/8)''' = 8:9:10:12:14:15 | |||
'''(x/9)''' = 9:10:12:14:15 | |||
'''(x/12)''' = 12:15:16:18:20 | |||
Some of these ratios are near each other, but not equal, such as 9/8 in the (x/8) and 10/9 in the (x/9) series or 14/9 in the (x/9) series and 11/7 in the x/7 series. | |||
One way to evenly distribute error is to take the harmonic/geometric median between such fractions e.g. square-root-of ((11/7)/(14/9)) * 14/9 = about 1.56. | |||
Doing such gives us the scale | |||
{| class="wikitable" | |||
|- | |||
|+ 10 note <<7-8-9-12>> "extended color diatonic" Harmonic Segment Scale | |||
|- | |||
| 1/1 | |||
| 11181/10000 | |||
| 5/4 | |||
| 9/7 | |||
| 4/3 | |||
| 3/2 | |||
| 156341/100000 | |||
| 5/3 | |||
| 26/15 | |||
| 28/15 | |||
|- | |||
| | |||
| between 10/9 and 9/8 | |||
| | |||
| | |||
| | |||
| | |||
| between 14/9 and 11/7 | |||
| | |||
| between 12/7 and 7/4 | |||
| between 13/7 and 15/8 | |||
|} | |||
In addition, adding 16/15 to the above scale can yield an additional 5 note harmonic series, making the above a '''larger <<7-8-9-12-15>> scale''' | |||
'''(x/15)''' = 15:16:20:26:28 | |||
And adding 6/5,8/5, and 9/5 gives | |||
'''<<7-8-9-10-12-15>> scale''' | |||
'''(x/10)''' = 10:12:15:16:18 | |||
Feel free to add comments or find/punch loopholes in this theory, but this is what I'd consider an idea '''"extended [[diatonic]]"''' scale in that it stresses likely the most important harmonic series in the diatonic scale while adding an extra (x/7) into the mix, giving the scale a wider range of tonal color. | |||
'''More scales to come later...''' | |||
----- | |||
'''Appendix''' | |||
Above calculations such as the interpolation of (11/7)/(14/9) can also be expressed as commas e.g. 99/98, which can be plugged into [[Graham Breed]]'s Temperament Finder on [http://x31eq.com/temper/uv.html http://x31eq.com/temper/uv.html] to reveal temperaments and ultimately scales likely to contain the above harmonic series segments. | |||
. However, most of the more advanced scales on my method would require tempering out several different [[comma]]s and, presumably, also countless related commas indirectly. I am afraid this would often result in huge and much more challenging to play in (think: well over 15 notes) scales needed to contain, say, the x/7,x/8,x/9,and x/12 harmonic series from the root tone with reasonable accuracy in [[regular temperament theory]]. | |||
If any '''experts on Xenharmonic math''', including related lists, can find a way to related the input of harmonic series segments to, say, [[MOS scale]]s guaranteed to have them I would really appreciate it. | |||
[[Category:Scale]] | |||
[[Category:Guides]] | |||
{{todo|cleanup}} | |||