small rant
ok. I gotta argue some of the specifics in this article. I'm no PhD in physics, but I do understand a little bit about the law of reflection (angle of incidence equals angle of reflectance) from far too many days of pool in the college rec room... The author basically states that the shape of an ear will "shadow" an auditory canal in the case of an offset source of sound. the "unshadowed ear hears more and the shadowed ear hears less, and the brain uses the difference to establish a point of origen.
I'm not buying this. Dogs, and especially cats, are orders of magnitude more efficient at detecting the origen of a sound point. their ear backs (with a linear edge) would cast a far greater "shadow" than the curved human ear. As far as the off-ear not being shadowed, the leading edge would also be linear, but is angled forward such that it would be prone to reflect outward, away from the auditory canal.
if we had a sound wave approach a human head (from a top view) from an off-angle position (the "red" sound in the diagram), there is a very good chance something would enter a human auditory canal. if the same is true of a animal (green) , the ears would clearly deflect sound AWAY from the auditory canal.
I would personally find it FAR more likely that the sound waves at some frequency, penetrate the ear and skull and disturb the fluid in the hearing chamber. the ear closest to the sound source would detect this first, resulting in the ability to locate. It has little or nothing to do with the ears shadowing the auditory canal.
I understand that my drawing shows a line of sound rather than a series of concentric waves radiating from a center, but if "shadowing" really exists then only the portion of the wave striking the ear can be considered for the author's argument....
I also apologize to all who are colorblind, I forgot the rule of not using green and red in the same diagram.
