Abstract: An improved audio mixing system that does not instantaneously switch a microphone from the attenuated level to the unattenuated level in response to level changes on the microphone is disclosed. The system is not limited to one type of microphone and does not depend on separate sensing microphones to determine the background noise level. In addition, the active signal is not amplitude modulated by extraneous noise inputted through inactive microphones.

Abstract: An improved audio mixing system. The system is not limited to one type of microphone and does not depend on separate sensing microphones to determine the background noise level. In addition, the active signal is not amplitude modulated by extraneous noise inputted through inactive microphones. The mixing system divides the system gain between a plurality of input channels. The mixing system periodically samples the channels and determines which channel is the dominant channel. In response to this determination, the gain of the dominant channel is increased and that of the other channels decreased.

Abstract: A sound system microphone equalization apparatus and method comprising a plurality of filters programmable by a microprocessor. User interfaces permit adjustment for each microphone channel of the parameters of the three notch filters, and four tone control filters in the filter network.

Abstract: A multichannel sound system comprising a plurality of microphones and loudspeakers. Rate controlled, variable attenuation of the audio signal is provided as a function of loudspeaker and microphone proximity. The use of optical isolators or analog switches with RC delay circuits to control the rate of attenuation eliminates objectionable switching transients. Selective attenuation of loudspeakers in proximity to active microphones eliminates audio feedback.