rhelsenborg wrote:

>> Whoa. Back up. Any noise above 85 db can do damage. In the Navy they
>> told us that highs did the damage but I can't find any medical support
>> for that.
>
> True enough about the 85 db limit. I have read somewhere years ago - not
> on the net - that bass sounds can damage speaker membranes earlier than
> high frequency sounds. The same is probably true for eardrums I imagine.
> Ever remove a speaker cover and feel (or see) the speaker movement from
> the bass? Or been in a car with a sub-woofer with the bass turned up
> high or at the max. I have. It was causing vibration in the glass/frame
> of my car. I have never felt that from high frequencies have you?

Sound is vibration, transmitted through the atmosphere in the form of
fluctuations in air pressure. Inside the cochlea (in the inner ear)
there are little hairs that respond to various frequencies. Those can be
destroyed by high levels of sound. There are a lot more of those
receptors for the mid ranges than there are for the high and low ranges,
so an equal amount of damage to the entire system causes relatively
greater loss at the extreme ends of the normal hearing range. With more
receptors in the mid ranges, the loss is less noticeable.

The ear is a specialized sensory system that helps to distinguish
sounds, even at high frequency, but the really low tones are slow enough
that the rest of the body can feel the vibration. Your car window may be
vibrating in time to the high frequencies too, but those are too fine
for you to see. The bass tones are slow enough for you to see the
vibration, and having a powerful sub woofer provides enough force to be
visibly noticeable and for you to feel the sound.