Dynamic Range

The difference in Sound Pressure Level between the saturation or overload level and the background noise level of an acoustic or electroacoustic system, measured in decibels. This range may be expressed as a signal-to-noise ratio for maximum output. Compare: Gain.

For a sound or a signal, its dynamic range is the difference between the loudest and quietest portions.

Compare: Loudness, Power, Volume.

The human hearing system has a dynamic range of about 120 dB between the threshold of hearing and threshold of pain. See: Recruitment.

The dynamic range of music may approach 90 dB, and since the maximum range is 55-60 dB for analog tape, and often less for disc recordings and optical soundtracks, compression is necessary in the recording of such signals. Noise reduction and companding equipment are designed to increase the dynamic range by 10-20 dB or more. The dynamic range of digital recording is generally over 90 dB.

See also: Limiter, Linear, Sound Synthesis, VU Meter. Compare: Dynamics, Silence.