The Sounds of Silence

This process is explained well by Karl F. Kuhn in his Basic Physics (1979, 1996). He uses the example of a radio or stereo speaker, and notes the vibration you will feel if you touch such a speaker while it is transferring sound energy. As the speaker cone moves outward (say to the right), the movement "...pushes the molecules of the air together in front of the speaker, causing a compression...the compression in the air moves away from the source." Meanwhile, the speaker cone is moving in the opposite direction (left) and "...producing a rarefaction in front of it. This rarefaction follows the compression through the air." Then the cone moves again (to the right) and the cycle continues. "Thus a sound wave moves away from the speaker through the air. The air itself is not moving away from the speaker; the molecules of air vibrate back and forth as the wave moves..." outward from the cone.

So, what does all this have to do with the sounds of silence? Have patience. I'm getting there.

It's All In Your Mind

Here's where your ears come in (assuming you have no damage to your hearing, of course). As Kuhn adds, "Your eardrum is somewhat similar to a speaker cone, but it is used as a receiver. When a compression hits the eardrum, the higher pressure causes the eardrum to move inward. Then the following rarefaction causes it to move outward. The vibrations are changed to electrical signals by the inner ear and then are transmitted to the brain for interpretation."

And that's the rub. For, if your brain can't interpret the signal it receives, you can't be said to hear. And we're not talking about "recognizing" the sound, but "interpreting" the electrical signal as a sound. Thus, in order to hear, 3 things are necessary:

• The sound wave must be intercepted by the eardrum (or some form of replacement).

• The resulting vibration must be changed to an electrical signal.

• Finally, that signal must be passed on and accepted by the brain as an existing impulse that it understands to be sound.

There are many kinds of damage which can impact some part of this process and either alter the nature of the hearing or disable it altogether.

There are other reasons for not being able to hear sounds, as well. Some sounds are too "high pitched" or "low pitched" to be registered by the human ear, and some are beyond the "hearing"

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