A pedal-tone holds one pitch while chords change above it, anchoring ambiguous harmony and adding tension

A pedal-tone (pedal point) holds a single pitch — usually the tonic or 5th — sustained while the chords move above it. Because the held note may or may not belong to each passing chord, it anchors otherwise ambiguous harmony and builds tension as the upper chords pull against the fixed bass. A droning bass under a moving pad is a pedal. It is a cheap way to add harmonic tension and cohesion without writing more chords, and it overlaps conceptually with the drone used for static techno harmony, differing in that the harmony above a pedal actually changes.

Examples

Hold A in the bass while the pad moves chord('<Am F G>') above it — the A is a tonic pedal; the F and G chords lean against it before resolving back.

Assessment

What does a pedal-tone hold, and what happens in the voices above it? Explain how a pedal adds tension, and how it differs from a plain drone.