Dynamic range

Dynamic range is a prime consideration in the hi-fi recording and reproduction.  In general, greater the dynamic range, better the sound quality over the wide range of volume levels. Dynamic range can be expressed in decibels (dB). The larger the dynamic-range specification in dB, better the system, all other factors being constant.At the low volume levels, limiting factor in dynamic range is background noise in the system. In the traditional analog system, most of this noise comes from audio amplification stages. In tape recording, there is some tape hiss. A scheme called as Dolby (which is a trademark of Dolby Laboratories) is used in the professional recording studios and in high-end consumer tape equipment also, to minimize this hiss. Digital recording techniques, such as is used in the compact disk (CD) or digital audio tape (DAT) recording, have much less internal noise than older analog systems.

At the high volume levels, power-handling capability of the audio amplifier limits the dynamic range. If all other factors are equal, a 100-watt system will have greater dynamic range than a 50-watt system. The speaker size is important; larger the speakers, greater the dynamic range. This is why serious audio enthusiasts at times purchase sound systems with amplifiers and speakers which seem unnecessarily large.

The reason for such over engineering is usually twofold:

(1) to ensure that sound peaks will always be distortion-free and cannot possibly damage speakers.
(2) to impress people.