Dynamic range   

The range of an audio systemís amplitude sensitivity; the maximum signal to noise ratio of the system.
For example a standard cassette deck has a dynamic range of 55 dB. this may also be referred to as signal to noise. This means the difference between the quietest sound it can record and the loudest sound it can capture without distortion is 55 dB. By contrast the human ear can accommodate a range of 120 dB or more though permanent hearing loss can occur with levels above 90 dB. Standard compact disc systems have a 96 dB range. a symphony orchestra playing Romantic music may have a dynamic range of as much as 108 dB.