380 BELL SYSTEM TECHNICAL JOURNAL 



V'lII. Conduction of Skui.l Between the Two Ears 



A comparison of the two curves in Fig. 4 sliows that the attenua- 

 tion introduced by the skull from one ear to the other when the tone 

 is introduced by a telephone receiver is between 4[) and 50 sensation 

 units corresponding to an intensity ratio of from 10^ to 10*. This 

 becomes 7 TU greater when rubber caps are interposed lietween the 

 head and the receiver cap. 



IX. Localization of Pure Tones as a Function of thk Phase 



Difference at the Tv;o Ears 



(G. W. -Stewart. Phys. Rn:. 2r,, p. 42r,. May, 1920) 

 The experimental results can be represented by the foriiuila 

 ^=0.0034A' + .8 (approx.) 



<l> is the phase difference in degrees of the tones at the two ears. 



is the number of degrees to the right or left of the median plane 

 that an observer locates the source of sound. The direction of 

 location is toward the ear leading in phase. 



A^ is the frequency of the tone in dv. The relation applies only for 

 frequencies of 100 to 1,000 dv., inrlusi\e. 



X. Constants Used in the Computation of thk Loudness of 



A Com PI EX Sound 



(Fletcher and Steinberg, Phys. Rn\. 24, p. 306, Sept., U)24) 

 (.Steinberg, Phys. Rci'. To he jniblished soon) 



II /. 1h' ilir loudness as judged In' an axerage normal car, then 

 L = 3.;5H log,, 



lof v^(ir„^)'T 



where 



/>n = rms pressure of the mih component, 

 W„ = a weight factor for the //''' component (I"ig. 5) 

 r = a root factor (I'ig. o) 



The sensation levels (.See I\') given in tiie chart are for the coniiilex 

 tone. 



