[all the audio processing notes are going to be labeled with Image/Video][To Audio label now, 9/22/09]
The amplitude of a sound wave is measured in decibels (dB), it is denoted in Hertz (Hz) in Frequency. The lowest amplitude we can hear is ‘threshold of hearing’, denoted with 0 dBSPL (sound pressure level). The sounds we can hear is about 20 ~ 20k Hz, and 2-4k Hz are the most sensitive to us.
The microphone converts sound wave to voltage:
dBV = 20 x log (x volt / 1.0 volt)
6dB describes the relation between dynamic range and computational word width:
Dynamic range = 6n dB, (n is the precision bits)