Effects of panel boundedness on sound transmission problems

A theory for sound transmission through a panel of finite width and infinite length mounted in a rigid baffle is formulated in order to discuss the effects of the panel boundedness on the sound transmission loss. The results calculated from a rigorous solution are presented as the frequency characteristics curves. However, it seems to be difficult to evaluate the sound insulation efficiency of the panel using the rigorous results, because of their violent peaks and dips owing to resonance. A method for averaging the response over any frequency band is discussed. The averaged response corresponds to the actual transmission measurement with a bandlimited excitation and allows one to evaluate the transmission characteristics from a viewpoint of practical noise control. The effects of the panel boundedness including a comparison with an infinite panel are also discussed by means of this method.