Add some stuff on measuring levels, e.g. peak vs RMS measures.
Add some general mathsy stuff on decibels, and the various types and domains of dB.
Note that the dynamic range of a digital system is the ration of the full-scale signal to the RMS noise floor.  In digital systems, the dynamic range is equal to the signal-to-noise ratio (SNR) and is ~96 dB for 16-bit audio.
Maybe a digression on power as well, esp. regarding power amplifier power output.


A section on dynamic range, signal-to-noise ratio, and headroom would be good:

"level" defined?

Also:
 - Dynamic range: the ratio of the loudest possible (clean) sound to the quietest (or inherent noise level (noise floor)).
 - Signal-to-noise ratio
 - Headroom: capacity of the system to capture or reproduce a signal cleanly above the nominal level.
 - Crest factor: the "musical headroom": the ratio of the loudest parts to the nominal level.
Thus, dynamic range = signal-to-noise ratio + headroom.