PHYSICAL FACTORS 



251 



-20 

 20 



30 60 90 120 ISO 180 



A -NEAR EAR 

 B- FAR EAR 



DIFFERENCE 



180' 



V 



-30 

 10 



-30 

 20 



-20 



30 60 90 120 150 180 



ANGLE IN DEGREES 



Fig. 



2 — Variation in loudness level as a sound source is rotated in a horizontal plane 

 around the head. 



