Patent ID: 7450727

Claim:
A method of establishing mix coefficients for downmixing a multi-channel input signal having a plurality of input channels, including a left input channel, center input channel, right input channel, or any combination thereof, to an output signal having a plurality of output channels, including a left output channel and a right output channel, comprising: with a processor in a downmixer: determining a left output channel energy responsive to at least one of the left and center input channels; determining a right output channel energy responsive to at least one of the right and center input channels; determining an input energy including determining at least one of a left channel total input energy responsive to at least one of the left and center input channels, and a right channel total input energy responsive to at least one of the right and center input channel; generating a left channel feedback constant responsive to at least one of the left channel total input energy and the left output channel energy; generating a right channel feedback constant responsive to at least one of the right channel total input energy and the right output channel energy; determining a limited-bandwidth mix coefficient based on at least one of the left and right channel feedback constants, and substantially preserving an apparent direction of the input signal in the output signal; updating a broad-bandwidth mix coefficient based on the limited-bandwidth mix coefficient; and storing the broad-bandwidth mix coefficient in a downmixer memory coupled to the processor.