114 



DIRECT RADIATOR LOUD SPEAKERS 



By suitable processing of the cone it is possible to reduce the mechanical 

 impedance at the higher frequencies. In any case, there is some wave 

 propagation in any diaphragm at the higher frequencies which in effect 

 reduces the impedance of the vibration system. 



»I0= ^ " ^\<^ 

 FREQUENCY 



Fig. 7.1. The impedance frequency characteristics of three cone loud speakers having 1-inch, 

 4-inch and 16-inch diameter cones and the efficiency frequency characteristics of the three 

 loud speakers, xmc = mechanical reactance of the cone and coil, xma = mechanical 

 reactance due to the air load, rMA = mechanical resistance due to the air load and m = 

 efficiency. 



The performance of the systems of Fig. 7.1 was considered from the 

 standpoint of efficiency. In certain cases it is desirable to examine the 

 performance from a consideration of the velocities in the equivalent elec- 



