Patent ID: 6614910
Filing Date: 2003-09-02
Classification: H04S

Abstract:
Stereo expansion apparatus comprising first and second inputs for receiving respective left and right stereo signals, the first input being coupled through a first channel which does not significantly alter the frequency characteristics of the stereo signal, to a first summing means and the first input being coupled, via a filter representing a far ear Head Related Transfer Function (HRTF), to a second summing means; and the second input being coupled through a second channel which does not significantly alter the frequency characteristics of the stereo signal to said second summing means, and, via a filter representing a far ear HRTF, to the first summing means, the outputs of the summing means providing stereo expanded signals; andwherein equalizing means is provided to compensate for a transfer function arising from the use of pan-potting to derive a stereo input signal from a mono signal, so as to create a tonal quality substantially similar to a stereo signal which has not been expanded.