440 



APPENDIX. 



Table 584. 

 MISCELLANEOUS SOUND DATA. 



TABLE 584. — Audibility as dependent on Sound Pressure and FtetiaencY. 



The auditory sense detects sounds varying over a range of pressure from about o.ooi to looo 

 dynes/cm^; over much of this range it differentiates with accuracy between complex sounds 

 so nearly alike that no existing physical device can distinguish them. Plot shows minimum 

 audibility pressures from 72 normal ears from 60 to 4000 cycles (both scales logarithmic); 

 standard deviation indicated by dotted curves. The maximum audibility curve was obtained 

 from 48 normal ears. A louder sound becomes painful. The intensity of pressure necessary 

 for the latter is about equal to that required to excite the tactile nerves in the finger tips. 

 (Wegel, Pr. Nat. Acad. Sc, 8, p. 155, 1922.) 



10000. 



1000. 



100. 



.01 



.001 



.0001 



Cycles per 



Second 



10 20 50 100 200 500 1000 2000 5000 



20000 5000O 



Smithsonian Tables. 



