Sondheim’s use of the ‘Herrmann chord’ in Sweeney Todd

When Stephen Sondheim approached the score for his 1979 musical thriller Sweeney Todd, the Demon Barber of Fleet Street, he felt compelled to write it as if it were the score for a horror film. Particularly inspired by the music of film composer Bernard Herrmann, Sondheim crafted his score around a quintessential harmony that Hermann used in most of his film scores: a minor/major seventh chord, or 4–19 (0148). Since this unstable sonority has qualities of both major and minor, its ambiguous particulars allow for many harmonic possibilities. Although the ‘Herrmann chord’ is conceived as a vertical harmony in a specific inversion (seventh in the bass), both Sondheim and Herrmann use this sonority in other fascinating ways. For this reason, my analysis will extend the ‘Herrmann chord’ to consider its intervallic constituents employing Pitch-Class Set Theory, which will allow for a broader, more expansive contextual study of Sweeney Todd.