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BELL SYSTEM TECHNICAL JOURNAL 



of frequency for several values of hjw. It is seen from these curves 

 that the resistance at the higher frequencies is determined very 

 largely by the relation of hjiv but is independent of it at the lower 

 frequencies, where it is equal to pcaT'^. At the lower frequencies 

 where the mechanical impedance of the diaphragm is negligible, the 

 efficiency, as was the case for the low frequency receiver, depends 



O 1.0 



FREQUENCY X 



4l 



Fig. 6 — Load iin]K'dancc of speaker (liapliragm. 



