ABSTRACT
This chapter examines nonfunctional pitch centricity and post-tonal approaches to harmony. A polychord is a combination of two or more distinct chords. True polychords are usually complete; moreover, the individual chords are often separated by register or timbre to differentiate them from one another. In a polychord label, the symbols for the component chords are arranged vertically and separated by a horizontal line, with the upper chord placed above the line and the lower chord beneath. The fourths and fifths are usually perfect, but augmented or diminished intervals may be mixed in. These harmonies sound noticeably different from tertian chords and may range in size from three to twelve chord members. Chords built from seconds create tone clusters. Clusters form a dissonant “blur” of sound that is primarily a textural, coloristic device. Clusters may be notated in a variety of ways, and composers often provide instructions in the score on how to execute them.
