Volume control system for public address network - uses detected level of output sound to control amplification of broadcast

摘要

In the public address system at least one pick-up (1) detects the level of the sound waves inside or outside at the public gathering. A signal is broadcast and the sound intensity (M) of the signal is controlled such that it varies in the same sense as the level of the detected waves (B). After detecting the waves, a control signal is produced as a result of the difference between the level of the broadcast signal (a function of M) and a sample signal whose value is a function of the intensity of detected waves.