A resonance that is similar to a shear resonance but for which there is also an axial node between the front and back of the horn. Under this condition, the instantaneous axial motion at a given location on the face will be opposite to the motion at the corresponding location on the back surface. Adjacent sections of the horn that are separated by shear nodes will also have opposite motion.
This resonance is found in block horns.
Also see axial resonance.