Diamond monotone: Difference between revisions
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my 1st non-userspace edit; this page's example seemed a little... abstract to me at first |
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While diamond tradeoff tunings are always guaranteed to occur, diamond monotone tunings are not. | While diamond tradeoff tunings are always guaranteed to occur, diamond monotone tunings are not. | ||
Let's look at an example: the temperament with mapping [{{val| 1 0 5 }}, {{val| 0 1 -2 }}]. | Let's look at an example: the rank-2 temperament with mapping [{{val| 1 0 5 }}, {{val| 0 1 -2 }}], tempering out [[45/32]]. | ||
All of this temperaments tunings are some linear combination of these two mapping rows. We could express that idea in the form {{nowrap|{{val| 1 0 5 }} + ''a''{{val| 0 1 -2 }} {{=}} {{val| 1 ''a'' 5-2''a'' }}}}. So one example tuning would be if this ''a'' variable was 7/5, which would give us the map {{nowrap|{{val|1 (7/5) 5-2(7/5)}} {{=}} {{val|1 7/5 25/5-14/5}} {{=}} {{val|5 7 11}}}}. Another example tuning would be if ''a'' was 4/3; then the map would be {{nowrap|{{val|1 (4/3) 5-2(4/3)}} {{=}} {{val|1 4/3 15/3-8/3}} {{=}} {{val|3 4 7}}}}. | All of this temperaments tunings are some linear combination of these two mapping rows. We could express that idea in the form {{nowrap|{{val| 1 0 5 }} + ''a''{{val| 0 1 -2 }} {{=}} {{val| 1 ''a'' 5-2''a'' }}}}. So one example tuning would be if this ''a'' variable was 7/5, which would give us the map {{nowrap|{{val|1 (7/5) 5-2(7/5)}} {{=}} {{val|1 7/5 25/5-14/5}} {{=}} {{val|5 7 11}}}}. Another example tuning would be if ''a'' was 4/3; then the map would be {{nowrap|{{val|1 (4/3) 5-2(4/3)}} {{=}} {{val|1 4/3 15/3-8/3}} {{=}} {{val|3 4 7}}}}. | ||
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#Now we need to make sure each of those are not negative, so we get a set of inequalities: {{nowrap|''a'' ≥ 4/3|''a'' ≤ 7/5|''a'' ≥ 1|''a'' ≥ 3/2}}. | #Now we need to make sure each of those are not negative, so we get a set of inequalities: {{nowrap|''a'' ≥ 4/3|''a'' ≤ 7/5|''a'' ≥ 1|''a'' ≥ 3/2}}. | ||
We can see that these inequalities have no solution: there's no way ''a'' can be both greater or equal to 1.5 and less than or equal to 1.4. Hence there are no diamond monotone tunings of this temperament. | We can see that these inequalities have no solution: there's no way ''a'' can be both greater or equal to 1.5 and less than or equal to 1.4. Hence there are no diamond monotone tunings of this temperament; any tuning must necessarily either map 6/5 wider than 5/4 or 4/3 wider than 3/2. | ||
== See also == | == See also == |