A description of the nominal audio signal strength resulting from a given input level and gain in an audio device or system. Level within analogue audio circuitry is often measured in dBu. The instantaneous signal strength, for any nominal level, can vary from the noise floor to the dynamic ceiling. Professional “line level” typically indicates a nominal level of +4 dBu, while “consumer level” typically indicates a nominal level of –10 dBu. See also ceiling, dBu, noise floor. Compare volume.