NUMIIRICII. CO\'ST.-IMS OV SI'IECII .txn III.INIM; i'" 



tion level (al)scissa) and fretiueniy .Vi of tlie masking; tone. In 

 Fig. 3 data for a niaskinj; Umc of 1,'2(M) dv is plotted in \v1h( ii liu- 

 frequencies of the masked tones are plotted on the abscissa. In order 

 to Ret satisfactory curves of this kind it is necessary to take more 



^« 



!«. 



to 40 60 80 too 120 

 MASKINO TONE 



f40 



1 20 



N2= 300( 



AA 



t 



^40 



1 40 



Kig. 4 — Masking Data. Tones in Opposite Kars. Masking Tone 1,200 Cycles 



comprehensive data than that shown in Kig. 2. The solid curves of 

 Fig. 4 show the masking when the masked and masking tones are 

 introduced into opposite ears. The dottefl curves were taken from 

 Fig. 2. 



