US Patent 7305097 Controlling fading and surround signal level

Systems and techniques for controlling a surround sound system having multiple input signals and multiple spatially diverse transducers may include defining a first control region and a second control region. When operating in the first control region, a first set of functions is performed. For example, for each of the spatially diverse transducers, an input signal may be selected, a relative strength of the selected input signal may be adjusted, and the adjusted input signal may be applied to the transducer. When operating in the second control region, a second set of functions is performed. For example, for each of the spatially diverse transducers, two or more input signals may be selected, a relative strength of the selected input signals may be adjusted, the adjusted input signals may be mixed, and the mixed input signals may be applied to the transducer.