The difference between the internal noise and the maximum level is the device's dynamic range.
When a signal is chained with improper gain staging through many devices, clipping may occur or the system may operate with reduced dynamic range.
VU meters are designed to represent the perceived loudness of a passage of music, or other audio content, measuring in volume units.
In most professional recording and sound reinforcement equipment, the nominal level is 0 VU = +4 dBu.
[3] This difference is due to the cost required to create larger power supplies and output higher levels.