Sound transmission properties assisted by the phase resonances of composite acoustic gratings.

We investigated composite gratings for their sound transmission properties induced by phase resonances. Each periodic unit of the composite grating consisted of a rectangular slit and a triangular slit. The triangular slit showed special properties in generating enhanced phase resonance and in restraining sound transmission. By adjusting the triangular slit's opening, we could regulate the frequency and sound transmission at phase resonance. These features of the composite grating can be used in designing acoustic filters for sound reduction. [ABSTRACT FROM AUTHOR]