Suggested Learning Resources
How to recognized and label two pitch-class-sets that are related by transposition...
- Arrange both sets in their ascending form that is most compact (around a clock
face)
- Subtract each integer of one set from its corresponding integer in the other set
(mod12)
- If the difference of each subtraction is the same, then the sets are related by
transposition
- Example: consider set X {2,0,t,e,9} and set Y {9,7,5,6,4}
- First arrange these in most compact ascending order. Set X becomes {9,t,e,0,2}
and set Y becomes {4,5,6,7,9}
- Now subtract (mod12) set Y from set X {9,t,e,0,2}
- These two sets are related by transposition of 5 half steps
- We label this relationship in the following way X=T5Y
- The T stands for 'transposition' and the 5 is the pitch-class-interval of transposition
between the two sets
- It is sometimes helpful to read the label backwards for clarity. "Y, transposed
by 5 results in X"
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How to find the index number and label two pitch-class-sets that are related by inversion...
- Arrange both sets in their ascending form that is most compact (around a clock
face)
- Reverse the order of one of the sets
- Add each integer of one set to the corresponding integer in the other set (mod12)
- If the sum of each addition is the same, then the sets are related by inversion,
and the 'distance/transposition' of the inversion is the resulting summed integer
- Example: consider set X {8,t,9,e,1} and set Y {t,9,7,e,0}
- First arrange these in the most compact ascending order. Set X becomes
{8,9,t,e,1} and set Y becomes {7,9,t,e,0}
- Reverse the order of one of the sets and add the other... (we'll reverse
X) {1,e,t,9,8}
- These two sets are related by inversion, and the distance of the inversion
is 8 half steps.... 8 is called the index number
- We label this relationship in the following way, X=T8IY
- I stands for 'inversion' and the T stands for the index number of
8
https://youtu.be/KgELJOpLNaE
Objective 53.1: Correctly label sets related by transposition with a Tx number, and
correctly label sets related by inversion with an index number