Patent val: Difference between revisions
Wikispaces>jdfreivald **Imported revision 247283603 - Original comment: ** |
Wikispaces>jdfreivald **Imported revision 247284699 - 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:jdfreivald|jdfreivald]] and made on <tt>2011-08-20 22: | : This revision was by author [[User:jdfreivald|jdfreivald]] and made on <tt>2011-08-20 22:15:32 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>247284699</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 val defines a rank 1 temperament by defining the deliberate introduction of an error into one or more primes. In 12 EDO, for instance, the perfect fifth (ratio 3/2, or exactly 1.5) is mapped to 700 cents, which is actually just barely flat: a ratio of 2^(700/1200), or 1.4983070769. | A val defines a rank 1 temperament by defining the deliberate introduction of an error into one or more primes. In 12 EDO, for instance, the perfect fifth (ratio 3/2, or exactly 1.5) is mapped to 700 cents, which is actually just barely flat: a ratio of 2^(700/1200), or 1.4983070769. | ||
As stated above, the 2/1 in the patent val is perfect. The patent val for 12 EDO, <12 19 28 34 42 (etc) |, implies that it takes 12 steps to get | As stated above, the 2/1 in the patent val is perfect. The patent val for 12 EDO, <12 19 28 34 42 (etc) |, implies that it takes 12 steps to get the octave. | ||
In the patent val for 12 EDO, the number 19 is in the second spot -- the place reserved for 3/1. That implies that it takes 19 | In the patent val for 12 EDO, the number 19 is in the second spot -- the place reserved for 3/1. That implies that it takes 19 steps to get to 3/1. We know this isn't precisely true, because we had to round to get these numbers in the first place. In essence, we're pretending 19 steps gets you to 3/1 in 12 EDO; in other words, we're deliberately introducing an error into 3/1. | ||
We can calculate the error we're introducing into 3/1 as follows for 12 EDO: | We can calculate the error we're introducing into 3/1 as follows for 12 EDO: | ||
12 EDO steps are 100.0 cents. | |||
12 EDO steps are 100.0 cents each. | |||
19 steps of 12 EDO = 19 steps * 100.0 cents/step = 1900.0 cents. | 19 steps of 12 EDO = 19 steps * 100.0 cents/step = 1900.0 cents. | ||
1900.0 cents => 2^(1900/1200), or 2.9966141538. This is the value that 12 EDO uses in place of prime 3. | 1900.0 cents => 2^(1900/1200), or 2.9966141538. This is the value that 12 EDO uses in place of prime 3. | ||
(Note that, for now, the example intervals (3/2, 4/3, 9/8) deliberately avoid any primes other than 3 and 2, and 2 is pure, so the sharpness and flatness comes only from the impure 3/1 value.) | That means that the 12 EDO patent val substitutes 2.9966141538 any time you would have had prime 3 in a ratio. 9/8 and 3/2 will be somewhat flat. 4/3 will be somewhat sharp. (Note that, for now, the example intervals (3/2, 4/3, 9/8) deliberately avoid any primes other than 3 and 2, and 2 is pure, so the sharpness and flatness comes only from the impure 3/1 value.) | ||
We can do the same calculations for 31 EDO. | |||
The patent val for 31 EDO is <31 49 72 87 107 (etc) |. The 49 implies that it takes 49 steps to get to 3/1. | |||
31 EDO steps are 38.70967742 cents. | 31 EDO steps are 38.70967742 cents each. | ||
49 steps of 31 EDO = 49 steps * 38.70967742 cents/step = 1896.774194 cents. | 49 steps of 31 EDO = 49 steps * 38.70967742 cents/step = 1896.774194 cents. | ||
1896.774194 cents => 2^(1896.774194/1200), or 2.991035765. This is what 31 EDO uses in place of prime 3 | 1896.774194 cents => 2^(1896.774194/1200), or 2.991035765. This is what 31 EDO uses in place of prime 3. | ||
Note that 31 EDO's prime 3 is a little farther away from 3/1 than 12 EDO's 3/1 -- i.e., it has a greater error. That means 31 EDO's 3/2 will be even flatter, and its 4/3 will be even sharper, than in 12 EDO. | Again, as in 12 EDO, it's less than 3, so 9/8 and 3/2 will be somewhat flat, and 4/3 will be somewhat sharp. Note that 31 EDO's prime 3 is a little farther away from 3/1 than 12 EDO's 3/1 -- i.e., it has a greater error. That means 31 EDO's 3/2 will be even flatter, and its 4/3 will be even sharper, than in 12 EDO. | ||
That doesn't make 31 EDO better or worse; it just means there's more error in the 3/1 ratio in 31 EDO than in 12 EDO. If you run these calculations for 5/1 using the patent vals for 12 EDO and 31 EDO, you'll find that 5/1 has more error in 12 EDO than in 31 EDO: 5.0396842 vs. 5.002262078, respectively. 31 EDO may therefore be preferred by people who like sweeter thirds (5/4 ratios) and are willing to have flatter fifths (3/2 ratios). | That doesn't make 31 EDO better or worse; it just means there's more error in the 3/1 ratio in 31 EDO than in 12 EDO. If you run these calculations for 5/1 using the patent vals for 12 EDO and 31 EDO, you'll find that 5/1 has more error in 12 EDO than in 31 EDO: 5.0396842 vs. 5.002262078, respectively. 31 EDO may therefore be preferred by people who like sweeter thirds (5/4 ratios) and are willing to have flatter fifths (3/2 ratios). | ||
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A val defines a rank 1 temperament by defining the deliberate introduction of an error into one or more primes. In 12 EDO, for instance, the perfect fifth (ratio 3/2, or exactly 1.5) is mapped to 700 cents, which is actually just barely flat: a ratio of 2^(700/1200), or 1.4983070769.<br /> | A val defines a rank 1 temperament by defining the deliberate introduction of an error into one or more primes. In 12 EDO, for instance, the perfect fifth (ratio 3/2, or exactly 1.5) is mapped to 700 cents, which is actually just barely flat: a ratio of 2^(700/1200), or 1.4983070769.<br /> | ||
<br /> | <br /> | ||
As stated above, the 2/1 in the patent val is perfect. The patent val for 12 EDO, &lt;12 19 28 34 42 (etc) |, implies that it takes 12 steps to get | As stated above, the 2/1 in the patent val is perfect. The patent val for 12 EDO, &lt;12 19 28 34 42 (etc) |, implies that it takes 12 steps to get the octave.<br /> | ||
<br /> | <br /> | ||
In the patent val for 12 EDO, the number 19 is in the second spot -- the place reserved for 3/1. That implies that it takes 19 | In the patent val for 12 EDO, the number 19 is in the second spot -- the place reserved for 3/1. That implies that it takes 19 steps to get to 3/1. We know this isn't precisely true, because we had to round to get these numbers in the first place. In essence, we're pretending 19 steps gets you to 3/1 in 12 EDO; in other words, we're deliberately introducing an error into 3/1.<br /> | ||
<br /> | <br /> | ||
We can calculate the error we're introducing into 3/1 as follows for 12 EDO:<br /> | We can calculate the error we're introducing into 3/1 as follows for 12 EDO:<br /> | ||
12 EDO steps are 100.0 cents.<br /> | <br /> | ||
12 EDO steps are 100.0 cents each.<br /> | |||
19 steps of 12 EDO = 19 steps * 100.0 cents/step = 1900.0 cents.<br /> | 19 steps of 12 EDO = 19 steps * 100.0 cents/step = 1900.0 cents.<br /> | ||
1900.0 cents =&gt; 2^(1900/1200), or 2.9966141538. This is the value that 12 EDO uses in place of prime 3.<br /> | 1900.0 cents =&gt; 2^(1900/1200), or 2.9966141538. This is the value that 12 EDO uses in place of prime 3.<br /> | ||
<br /> | <br /> | ||
(Note that, for now, the example intervals (3/2, 4/3, 9/8) deliberately avoid any primes other than 3 and 2, and 2 is pure, so the sharpness and flatness comes only from the impure 3/1 value.)<br /> | That means that the 12 EDO patent val substitutes 2.9966141538 any time you would have had prime 3 in a ratio. 9/8 and 3/2 will be somewhat flat. 4/3 will be somewhat sharp. (Note that, for now, the example intervals (3/2, 4/3, 9/8) deliberately avoid any primes other than 3 and 2, and 2 is pure, so the sharpness and flatness comes only from the impure 3/1 value.)<br /> | ||
<br /> | |||
We can do the same calculations for 31 EDO.<br /> | |||
<br /> | <br /> | ||
The patent val for 31 EDO is &lt;31 49 72 87 107 (etc) |. The 49 implies that it takes 49 steps to get to 3/1.<br /> | |||
31 EDO steps are 38.70967742 cents.<br /> | 31 EDO steps are 38.70967742 cents each.<br /> | ||
49 steps of 31 EDO = 49 steps * 38.70967742 cents/step = 1896.774194 cents.<br /> | 49 steps of 31 EDO = 49 steps * 38.70967742 cents/step = 1896.774194 cents.<br /> | ||
1896.774194 cents =&gt; 2^(1896.774194/1200), or 2.991035765. This is what 31 EDO uses in place of prime 3 | 1896.774194 cents =&gt; 2^(1896.774194/1200), or 2.991035765. This is what 31 EDO uses in place of prime 3.<br /> | ||
<br /> | <br /> | ||
Note that 31 EDO's prime 3 is a little farther away from 3/1 than 12 EDO's 3/1 -- i.e., it has a greater error. That means 31 EDO's 3/2 will be even flatter, and its 4/3 will be even sharper, than in 12 EDO.<br /> | Again, as in 12 EDO, it's less than 3, so 9/8 and 3/2 will be somewhat flat, and 4/3 will be somewhat sharp. Note that 31 EDO's prime 3 is a little farther away from 3/1 than 12 EDO's 3/1 -- i.e., it has a greater error. That means 31 EDO's 3/2 will be even flatter, and its 4/3 will be even sharper, than in 12 EDO.<br /> | ||
<br /> | <br /> | ||
That doesn't make 31 EDO better or worse; it just means there's more error in the 3/1 ratio in 31 EDO than in 12 EDO. If you run these calculations for 5/1 using the patent vals for 12 EDO and 31 EDO, you'll find that 5/1 has more error in 12 EDO than in 31 EDO: 5.0396842 vs. 5.002262078, respectively. 31 EDO may therefore be preferred by people who like sweeter thirds (5/4 ratios) and are willing to have flatter fifths (3/2 ratios).<br /> | That doesn't make 31 EDO better or worse; it just means there's more error in the 3/1 ratio in 31 EDO than in 12 EDO. If you run these calculations for 5/1 using the patent vals for 12 EDO and 31 EDO, you'll find that 5/1 has more error in 12 EDO than in 31 EDO: 5.0396842 vs. 5.002262078, respectively. 31 EDO may therefore be preferred by people who like sweeter thirds (5/4 ratios) and are willing to have flatter fifths (3/2 ratios).<br /> | ||