Theory Orals: Post-Tonal Flashcards
What is the interval vector?
A systematic listing of all intervals within a given set. Displayed with Interval Classes.
What is the interval vector used for?
To determine how many common tones are preserved during transposition or whether a set can map onto itself during transposition.
What is the index vector? How is it useful?
o Tallies the number of common tones found in the summation square, but in an easy to read row format.
What is the summation square?
Determines the number of common tones under Inversion. Determines if a Set is Inversionally related.
What is invariance?
The preservation of some aspect of a row under transposition or inversion.
With which composer is Invariance associated?
Anton Webern
In a given row, how do you preserve an adjacent segment of, say, three notes in a second row?
This is determined by finding the prime form of a set and seeing if any other sets within the row match. If so, is it by transposition or inversion? From there, transpose or invert the row to keep that particular set invariant.
How do you determine inversional symmetry?
One must look at the AIS of two given sets and determine if each AIS can be positioned as mirror images of one another. If so, then the sets are inversionally symmetrical.
Why is Inversional Symmetry significant?
All sets are transpositionally related, even if just by the trivial case of T¬0, but not all sets are inversionally related. So, the ones that are inversionally symmetrical are far more interesting and significant.
Name a piece that includes the technique of hexachordal combinatoriality.
Schoenberg: String Quartet No. 4 or Klavierstücke, op. 33a
Define Hexachordal combinatoriality?
Combinatorial rows are those that can produce a transposition, inversion, retrograde, and/or retrograde inversion in which the first six pitches, or hexachord, or the new row will be completely different than the first hexachord of the former. In other words, the first hexachord of both the old and the new rows will create an aggregate.
Name the 6 all-combinatorial hexachords.
(012345), (02468T), (014589), (012678), (023457), (024579)
How many Major triads are in an octatonic collection?
FOUR - As well as 4 minor and diminished triads, as well as 4 Mm 7ths, mm 7ths, and fully diminished 7ths.
What is the relationship between (0146) and (0137)?
- -They have the same interval-class vector: [1,1,1,1,1,1]
- -They are “All Interval-Class” Tetrachords
- -They are also Z-related, meaning that they have different prime forms, but the same interval vector.
What is the relationship between set classes that have the same interval vector?
They are “Z-Related,” meaning that they have different prime forms, but the same interval vector.