The transmission of sound through thin elastic plates set in a plane infinite baffle or an infinite duct is discussed in some detail. A two‐dimensional configuration is considered in both instances. The problems then are the transmission through a strip set in an infinite baffle and transmission through a plate set in a duct supporting lowest mode propagation.
These systems make it possible to indicate in a formal manner how the boundary conditions affect transmission. The notion of bending impedance is used as a means of categorizing the mounting conditions.
Experimental investigations of the transmission through circular plates in ducts of the same cross section were carried ont. It is shown that the transmission loss varies with the manner in which the plates are mounted. The conditions under which this behavior is predictable are discussed.