Dynamic Range
From WikiRecording
Audio engineers often use dynamic range to describe the ratio of the loudest possible undistorted sound to the quietest or to the noise level, say of a microphone or loudspeaker. In digital audio, the maximum possible dynamic range is given by the audio bit depth (see signal-to-noise ratio). Dynamic range of an audio device is also sometimes referred to as the dynamic window.
The dynamic range is defined as the difference between the minimum and maximum amplitude a given device can record. For example, if the ceiling of a device is 10 dB and the noise floor is 3 dB then the dynamic range is 4.85 dB, since 10 dB−3 dB = 4.85 dB (recall that care must be taken when adding numbers in the decibel scale). In digital audio systems the dynamic range is limited by quantization error. The maximum achievable dynamic range for a digital audio system is approximately (6 * bit-depth) dB. For CD audio, which is 16-bits, the corresponding dynamic range is 96.33 dB.
In the analog domain multiple noise processes determine the noise floor of a system and its corresponding dynamic range. Magnetic tape has a dynamic range of approximately 55dB. A vinyl disk has a dynamic range of approximately 65dB.
Since the early 1990s it has been recommended by several authorities including the Audio Engineering Society that measurements of dynamic range be made with an audio signal present. This avoids questionable measurements based on the use of blank media, or muting circuits.
Citation
Dynamic range. (2008, February 29). In Wikipedia, The Free Encyclopedia. Retrieved 02:53, March 13, 2008, from http://en.wikipedia.org/w/index.php?title=Dynamic_range&oldid=194836477
