When we bite hard biscuit, we hear a deafening noise, while our neighbors eat those crackers without any noticeable noise. How they manage to avoid this crash?
The fact that the noise and rumble exist only in our ears and a little concerned about the ears of our neighbors. The bones of the skull, and generally solid, elastic body, very good sounds, and sound in a dense environment increases sometimes to extraordinary proportions. Reaching up to the ear through the air, the crackling of dry bread is perceived as light noise; but the same crash turns into a roar, if it comes to the auditory nerve through the hard bone of the skull. Here's another experience of the same field: pinch between your teeth ring pocket watch and close your fingers in your ears: you will hear heavy blows - so will increase the ticking of the clock.
Beethoven, agohow, listened to, say, play the piano, put to it one end of his cane, the other end of which he held in his teeth. Similarly, those deaf people who have survived the inner ear, can dance to the music: the sounds reach their auditory nerves through the floor and bones.