Reed Piano

Left: the reed from the side (height exaggerated), the hammer below, the comb at the tip. Right: the slot end-on, with the potential solved as the reed moves; the grounded reed draws the field lines from the charged comb, most strongly where they overlap.

Reed–comb capacitance vs the reed's height above the comb's mid-plane, from Laplace's equation. Band: this strike's swing; line: the rest height. Below: the comb voltage it produces. A swing that reaches over the top of the curve folds the waveform: even harmonics, the bark.

Markers: the reed's own bending modes, inharmonic (mode 2 at 6–11 × f₁) and faint after the felt. The harmonics on the faint grid come from the pickup's C(y), not from the reed.

The reed's second bending mode (the tick above the note's) dies soon after the strike. The harmonics that remain come from the pickup, so they fade with the fundamental, and a soft note has fewer of them.

This key's reed and its bending modes (FEM): ratio to f₁ beside a bare cantilever's, ring time, and each mode's level at the slot after the last strike.