Introduction
The human ear is a rather wondrous instrument. It is composed of tens of thousands of component parts and can work quite flawlessly from well before we are born to more than a century of age, and is capable of performing extremely sophisticated auditory tasks. It works 24 hours a day! In addition to helping us hear, the ear also contains our primary organ of balance.

The normal healthy human ear can hear sounds at a frequency as low as 20Hz (20 vibrations of the eardrum per second), all the way up to a frequency as high as 20,000Hz (20,000 vibrations of the eardrum per second)!

The ear is able to hear the very slightest whisper of sound, 0 dB SPL or less, and yet, is able to tolerate very high intensity sounds in excess of 115 dB SPL for short periods of time.

Two normally functioning ears allow us to make extremely accurate decisions about the exact location of a sound source. The normal ear is able to discriminate a complex sound such as speech against a background of noise. The normal ear is able to differentiate the component parts of complex sounds whose characteristics have extremely sophisticated inter-relationships, such as a musical chord. The ear is capable of analyzing tiny changes in the frequency of sound, the intensity of sound, the duration of sound, the direction of sound, and in the interplay of harmonies. When all aspects of the human ear are considered, the ear is far more complex and sophisticated in design and function than any auditory apparatus that current technology has thus far allowed us to develop.