Patent ID: 7715567

Claim:
A method to reduce noise for a stereo signal comprising a stereo sum signal and a stereo difference signal to be used with a noise reducing device, said method comprising: dividing the stereo difference signal into a first plurality of subbands each subband covering a frequency band; dividing the stereo sum signal into a second plurality of subbands in a same manner as the stereo difference signal is divided in the dividing the stereo difference signal; determining a signal component of the stereo signal in the frequency band of each of the first and second plurality of subbands; determining a noise component of the stereo difference signal of each subband of said first plurality of subbands; attenuating, with the noise reducing device, the subbands of the stereo difference signal with a noise component of a respective subband lying above a masking threshold of the stereo signal of the respective subband until the noise component of the respective subband lies below the masking threshold; and adding the corresponding stereo difference signal with the corresponding stereo sum signal from said first and second plurality of subbands.