Patent ID: 7391869

Claim:
A method for processing a plurality of audio input signals into a plurality of audio output signals, the plurality of audio output signals being a greater number than the plurality of audio input signals, comprising: producing a plurality of initial low frequency input signals that comprise portions of the plurality of audio input signals that are at most about a cut-off frequency; producing at least one additional low frequency input signal from the plurality of initial low frequency input signals; producing a plurality of high frequency input signals that comprises portions of the plurality of audio input signals that are at least about the cut-off frequency; decoding the plurality of high frequency input signals into a plurality of high frequency output signals according to a matrix decoding technique; bypassing decoding of the said plurality of initial low frequency input signals and the additional low frequency input signal by any matrix decoding technique; and maintaining each of the said plurality of initial low frequency input signals and the additional low frequency input signal separately from each other, where the plurality of high frequency output signals, the plurality of initial low frequency input signals, and the additional low frequency input signal are included in the plurality of audio output signals.