built almost exclusively from the interval of a fourth," and his later reference to a "virtual fourth chord" miss the salient point of the first half of this song: it is built entirely around overlapping transpositions of the  trichord
(for example, C-C#-F # ).
If fluent in Babbitt's earlier practices, one would expect the partitions to be symmetrical, and for each hexachord and trichord
to share similar set classes and be combinatorial and complementary with one another.
The second feature missing in Alegant's account is the minor triad for P forms or major triad for I forms that occurs as the final trichord
in Dallapiccola's row.
An element of Webern's style that is much in evidence in these songs, and which is an important tool in learning and listening to them, is the trichord
In the early 1960s, State departments of transportation (DOTs) began using aluminum trichord
overhead structures to support signs along our Nation's highways.
But the primary function of Carter's twelve-note chords is to serve, in Mead's words, "as a background grid against which collections of smaller cardinality are projected." (8) Jonathan Bernard relates this function to the composer's "deliberately global" use of smaller pitch sets--for instance, the systematic inclusion of all possible trichord
types in the Piano Concerto, all possible tetrachord types in String Quartet No.
In the 7th Leaf there is a conspicuous calming passage in which all the orchestral instruments fall silent and the solo flute brings what is the very first projection of the motif (which consists of seven notes) that works in contrast to the earlier motifs produced within the fra mework of the single trichord
B, C, C sharp.
Blocks 1, 2, 5 and 6 reassemble the accompaniment's reiterated trichord
in close position in a higher register, and blocks 3 and 7 add a drone bass; but in none of those passages does one pitch class assert superiority.
In fact, an instance of this trichord
type can be formed with every pitch class of an octatonic collection.
(17) We can also correlate the occurrences of a set class with its degree of symmetry: the lower the Ds, the more likely that trichord
will appear--and vice versa.
Collection-classes such as the 0369 tetrachord, the 0145 tetrachord, the 048 trichord
, the 036 trichord
, or the 06 dyad have a special place in his tone rows, and are strategically and explicitly placed.