Monzo: Difference between revisions

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For example, the interval [[15/8]] can be thought of as having <math>5 \cdot 3</math> in the numerator, and <math>2 \cdot 2 \cdot 2</math> in the denominator. This can be compactly represented by the expression <math>2^{-3} \cdot 3^1 \cdot 5^1</math>, which is exactly equal to 15/8. We construct the monzo by taking the exponent from each prime, in order, and placing them within the {{monzo| … }} brackets, hence yielding {{monzo| -3 1 1 }}.  
For example, the interval [[15/8]] can be thought of as having <math>5 \cdot 3</math> in the numerator, and <math>2 \cdot 2 \cdot 2</math> in the denominator. This can be compactly represented by the expression <math>2^{-3} \cdot 3^1 \cdot 5^1</math>, which is exactly equal to 15/8. We construct the monzo by taking the exponent from each prime, in order, and placing them within the {{monzo| … }} brackets, hence yielding {{monzo| -3 1 1 }}.  


:'''Practical hint:''' the monzo template helps you getting correct brackets ([[Template:Monzo|read more…]]).
Here are some common [[5-limit]] monzos, along with their factorizations to show how to derive them:
 
Here are some common [[5-limit]] monzos, for your reference:


{| class="wikitable center-1"
{| class="wikitable center-1"
|-
|-
! Ratio
! Ratio
! Factors
! Monzo
! Monzo
|-
|-
| [[3/2]]
| [[3/2]]
| <math>2^{-1} \cdot 3</math>
| {{monzo| -1 1 0 }}
| {{monzo| -1 1 0 }}
|-
|-
| [[5/4]]
| [[5/4]]
| <math>2^{-2} \cdot 5</math>
| {{monzo| -2 0 1 }}
| {{monzo| -2 0 1 }}
|-
|-
| [[9/8]]
| [[9/8]]
| <math>2^{-3} \cdot 3^2</math>
| {{monzo| -3 2 0 }}
| {{monzo| -3 2 0 }}
|-
|-
| [[81/80]]
| [[81/80]]
| <math>2^{-4} \cdot 3^4 \cdot 5^{-1}</math>
| {{monzo| -4 4 -1 }}
| {{monzo| -4 4 -1 }}
|}
|}
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|-
|-
! Ratio
! Ratio
! Factors
! Monzo
! Monzo
|-
|-
| [[7/4]]
| [[7/4]]
| <math>2^{-2} \cdot 7</math>
| {{monzo| -2 0 0 1 }}
| {{monzo| -2 0 0 1 }}
|-
|-
| [[7/6]]
| [[7/6]]
| <math>2^{-1} \cdot 3^{-1} \cdot 7</math>
| {{monzo| -1 -1 0 1 }}
| {{monzo| -1 -1 0 1 }}
|-
|-
| [[7/5]]
| [[7/5]]
| <math>5^{-1} \cdot 7</math>
| {{monzo| 0 0 -1 1 }}
| {{monzo| 0 0 -1 1 }}
|}
|}
:'''Practical hint:''' On the wiki, the monzo template helps you getting correct brackets ([[Template:Monzo|read more…]]).


== Relationship with vals ==
== Relationship with vals ==
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=== Subgroup monzos ===
=== Subgroup monzos ===
{{Main|Smonzos and svals}}
{{Main|Subgroup monzos and vals}}
A subgroup monzo is like a standard monzo, except that it is in a just intonation [[subgroup]] that is not a prime limit. It is usually provided along with the subgroup it is in, such as 2.3.7 [1 -2 1⟩ for 14/9 or 2.3.13/5 [1 -1 1⟩ for 26/15. For subgroups with primes as basis elements (such as 2.3.7), a subgroup monzo can be seen as a standard monzo abbreviated to hide zeroes. To make this more clear, the abbreviated sections may be replaced with ellipses, such as 2.3.7 [1 -2 ... 1⟩ for 14/9.  
A subgroup monzo is like a standard monzo, except that it is in a just intonation [[subgroup]] that is not a prime limit. It is usually provided along with the subgroup it is in, such as 2.3.7 [1 -2 1⟩ for 14/9 or 2.3.13/5 [1 -1 1⟩ for 26/15. For subgroups with primes as basis elements (such as 2.3.7), a subgroup monzo can be seen as a standard monzo abbreviated to hide zeroes. To make this more clear, the abbreviated sections may be replaced with ellipses, such as 2.3.7 [1 -2 ... 1⟩ for 14/9.  


=== Tempered monzos ===
=== Tempered monzos ===
{{Main|Tmonzos and tvals}}
{{Main|Tempered monzos and vals}}
A tempered monzo represents a tempered interval, or an interval in a regular temperament. It functions similarly to a subgroup monzo, except each entry represents not a JI interval but a generator for that regular temperament. For example, the tmonzo for the major third in meantone (or more generally, the diatonic major third in a fifth-generated temperament) is ~2.~3 [-6 4⟩. (Note that we write the generators with tildes to indicate that they are tempered intervals). This means that to find the major third, you go up four perfect twelfths (~3/1) and down six octaves (~2/1).  
A tempered monzo represents a tempered interval, or an interval in a regular temperament. It functions similarly to a subgroup monzo, except each entry represents not a JI interval but a generator for that regular temperament. For example, the tmonzo for the major third in meantone (or more generally, the diatonic major third in a fifth-generated temperament) is ~2.~3 [-6 4⟩. (Note that we write the generators with tildes to indicate that they are tempered intervals). This means that to find the major third, you go up four perfect twelfths (~3/1) and down six octaves (~2/1).