The Petrushka chord is a chord made famous by Stravinsky in his ballet Petrushka. It combines two major triads whose roots are spaced by a tritone. For instance, a C major triad combined with an F# major triad creates the Petrushka chord.
In this blog, I thought I’d talk about a chord we can consider a companion to the Petrushka chord. The companion chord uses two minor triads whose roots are a tritone apart. For instance, D minor combined with G# minor is one version of the companion chord.
The companion chord has a similar sound to the Petrushka chord, as both chords combine two triads spaced by a tritone. But they are not exactly the same… The companion chord is built with minor triads rather than major triads, creating a slightly different sonority.
Interestingly, the companion chord above uses the six pitches in the chromatic scale that the Petrushka chord does **not** use. For instance, the Petrushka chord above used C, C#, E, F#, G and A#. The pitches missing are D, D#, F, G#, A, and B—the exact pitches that make up the companion chord above.
Given these characteristics, the companion chord makes a great counterpart for the Petrushka chord. One possible use is to alternate back and forth between the two chords, much like we alternate between tonic and dominant in tonal music.
Another use is to build a melodic phrase out of the pitches in the Petrushka chord—and when the phrase concludes, “resolve” to a pitch in the companion chord.
Each of these chords is highly dissonant and arguably uneasy to listen to. While they would be impractical in some musical settings, they can be useful when emotions are fear, suspense and/or horror are desired.
Notably, their perceived dissonance level can be lessened or intensified by condensing or spreading out the chord tones. A very dissonant version places each chord tone within one octave.
A less dissonant version spreads the chord out across multiple octaves and avoids major and minor seconds.