Sound system employing automatic proportional amplification

Claim 1

A multichannel sound system for providing voice pickup and distribution in a common area, the system comprising: a plurality of audio signal sources, an active one of which provides an audio input signal; a plurality of loudspeakers for distributing sound represented by said audio input signal in the same general area as that in which said plurality of audio signal sources is located, at least one of said plurality of loudspeakers being separately associated with and located in close proximity to each one of said plurality of audio signal sources; a plurality of line amplification means, each of which is coupled to one or more of said plurality of loudspeakers and adapted to receive said audio input signal; a plurality of level switching networks, each of which is coupled between said plurality of audio signal sources and one of said plurality of line amplification means for selectively attenuating the audio input signal before it is applied to said plurality of line amplification means; logic source means for supplying a logic input signal indicative of which of said plurality of audio input signal sources is active; and a plurality of control logic means, each of which is coupled to receive said logic input signal and is further coupled to an associated one of said plurality of level switching networks for selectively controlling the level of attenuation of said audio input signal by that level switching network.