A VOICE AND EAR 307 



of a tube terminated by an acoustic resistance. The purpose of this 

 leak, which has both mass and resistance, is to simulate the leak 

 between a receiver cap and a typical human ear. The molded rubber 

 insert is attached to a rigid structure in which a chamber has been 



Fig. 12 — -Artificial ear coupler. 



provided to simulate the size and, to some extent, the shape of the 

 auditory canal of a human ear. The diaphragm of the small con- 

 denser transmitter has been placed in the wall of this chamber to 

 measure the pressures developed. The chamber is terminated by an 

 acoustic network having mass, stiffness and resistance components of 



