two corners (fig. 1 and 2). The amount of coupling could 

 then be controlled by moving the transducers closer to or 

 further away from the corners. 



The transducers first utilized (shown in cross section 

 in fig. 3B) were found superior in performance to the 

 usual type (fig. 3A). However, the losses introduced by 

 the transducers were still significant, since it was possible 

 to improve the over -all Q of the resonant cavity by moving 

 the transducers closer to the corners. An effort was there- 

 fore made to improve the transducers. 



BARIUMTITANATE CYLINDER 

 RUBBER WASHER / ^RUBBER F 



RUBBER SOCK - ^assgrngsassssfegssi , 

 BRASS 



STAINLESS 

 STEEL BAND 



COAXIAL CABLE 



EPOXY COAT 

 PLEXIGLAS 



10-32 

 FIBER 



4-40 BRASS TUBE 



DIPPED NEOPRENE COAT 



Figure 3. Sound transducers. A, B, preliminary models; 

 C, final design. 



The final transducer design is shown in figure 3C. The 

 greatest improvements were accomplished by omitting all 

 soft material between the cylinder and the metal parts, and 

 by using an exterior coating of dipped Neoprene rubber. 

 The soft gaskets used in the transducer (fig. 3A) were re- 

 placed by a very thin film of epoxy cement, and it may be 



17 



