Sound in the Outer Ear

The intensity of the sound in the auditory canal is dependent on

• direction of sound reaching listener;
• shoulders: can reflect sound toward the pinnae;
• head: can cast an acoustical shadow;
• pinna: ``guiding'' filtering effect increases with increasing frequency (though at high frequency rises and falls).

Effects of pinna, the head, and shoulders is greatest when the sound's wavelength is comparable to their size:

• shoulders and head (6-8'' wide) might influence a musical pitch of A6 (wavelength $\approx$ 7.7'')
• the pinnae (2'' wide) might influence a musical pitch of A8 (wavelength $\approx$ 1.9'')