BookatlasPiano Rabbit Hole: Improvisation Theory & Practice
9800 / 18210 · Workshop 81 — Polychords and Bitonal Hearing: Two Harmonic Worlds at Once, Upper Structure vs. True Polychord, Controlled Clashes, and Making “Wrong” Chords Sound Intentional← prev⊞ allnext →

81.10Too much agreement collapses the two layers

If two triads share many pitches and functions:

the ear combines them into one ordinary chord.

For true polychordal effect, you often need enough difference that both layers retain identity.