What typically causes the head shadow effect?

The head shadow effect is primarily caused by the way that sound waves interact with the head and ears, particularly influenced by the frequency of the sound. When a sound source is located to one side of the listener, higher frequency sounds tend to be absorbed or deflected by the head, creating an area on the opposite side where sound is reduced or diminished, hence the term "head shadow." This phenomenon assists with sound localization, allowing individuals to determine the direction of a sound source more effectively.

Lower frequency sounds have longer wavelengths that can easily diffract around the head, making them less susceptible to being shadowed by the head's physical presence. This means that the head shadow effect is frequency-dependent, with higher frequencies being more significantly affected than lower ones.

The size of the outer ear, bone structure of the skull, and the angle of sound entering the ears do contribute to hearing perception but are not the primary reasons for the head shadow effect. The true distinguishing factor is the interaction of sound wave frequencies with respect to the listener's head.