# Antisymmetric resonance

A mode in which the amplitude is 180° out of phase (i.e., exactly opposite in phase) at symmetric locations on the same resonator and for which the mode would appear symmetric if only the magnitudes (absolute values) of the amplitude were considered. Since the amplitudes are 180° out of phase, there must be at least one node between the symmetric locations in which case the resonance must be nonaxial.

Example: a bar horn has a resonance where the instantaneous amplitude at one end of the horn face is +100 microns, while at the same instant the amplitude at the other end of the horn face is -90 microns. Note that the amplitudes at either end of the horn face are opposite in phase (sign), which indicates an antisymmetric mode, even though the magnitude of the amplitudes is not necessarily equal (100 microns versus 90 microns).

Also see —

Asymmetric amplitude

Symmetric resonance