Deafening Sound: Noise in the City

In this clip from the documentary Deafening Sound, Nancy Nadler, president of the League for the Hard of Hearing in New York City measures the decibel level at a crowded street corner.

In other portions of this documentary, chronic ringing in the ear, or tinnitus, is also discussed. When one loses the ability to hear over time what is typically occurring physiologically? What is the source of tinnitus? What is the experience like?