MINIATURE CONDENSER MICROPHONE SYSTEM 

 Elimination of pi and Vi from the first three equations gives 



461 



(5) 



= V(cos kl — b sin kiy + a^ sin^ kl 



as the expression for the change in acoustic pressure on a diaphragm, 



caused by the entrance cavity.^ It is plotted as db gain in Fig. 3. 



Similar calculations have been given by other writers.'- ^ 



* Numerical values of the functions a {kR) and b{kR) are given in Crandall's 

 "Theory of \'ibrating Systems and Sound," Fig. 19, p. 172. 



3 LqC. Clt, 



s W. West, in Jour. I. E. E., April, 1930. 



