Music Theory: Polychords

A Polychord is two (2) chords played at the same time, one superimposed upon the other. When played together, they create one composite chord. Polychords allow you to create voicings for different choirs (sections) that are harmonious amongst itself.

Example: Let's say we have 3 trombones and 3 trumpets, and we want them to play a CMaj9 chord together. Using the Polychord approach, we can give each choir (trumpets/trombones) a major triad to play. We always want to put the base of the chord (CMaj Triad) in the bottom, or Trombones in this case. Next, we give the trumpets the upper extensions and have them play a GMaj triad. Each choir now has a strong chord shape of a major triad. When they play G/C, we get the following notes. Trombones = C (Root), E (Major 3rd), & G (5th). Trumpets = G (5th), B (Major 7th) and D (Major 9th). Together they sound a CMaj9 chord. Remember to put the base of the chord (C Major in this case) in the bottom voices and the extension (G Major in this case) in the top.

C Major 9 Polychord

A Polychord can also be a triad over a single bass note. This provides a unique sound, and was used quite extensively in 1980's and 1990's television and pop tunes. The nature of this type of sound is the missing chord tones (which are implied), plus the strength of the triad. An example would be a C triad over G note, to D triad over G note, F triad over G note (creates a pedal tone in this example).

3 triads over bass note polychord

Polychord Chart (Key of C): This is a starting point for Polychords. You can quickly see how they are constructed, and can easily create your own polychords using the principles shown here..

I Major Chords:

CMaj9 = G/C

CMaj9(#11) = Bmin/C

CMaj13(#11) = D/C

I Minor Chords:

CminMaj9 = G/Cmin

CminMaj13 = Dmin/Cmin

CminMaj13 = F/Cmin

II Minor Chords:

Dmin9 = Amin/Dmin

Dmin11 = C/Dmin

Cmin13 = Emin/Dmin

V7 Dominant Chords:

G9 = Dmin/G7

G11 = F/G(bass note)

G13 =C/G7(omit 3rd)