Patent ID: 8229143

Claim:
A method for providing a stereo-widened sound in a stereo speaker setup comprising: (a) determining actual speaker angles alpha and beta relative to listener position wherein said speaker angles are computed using actual stereo speaker spacing and listener position; (b) determining actual inter-aural delays between the speakers and the listener ears; (c) determining the actual headshadow responses associated with each ear relative to each of the speakers given the speaker angles; (d) determining an actual speaker to listener transfer function H using the actual inter-aural delays and the actual headshadow responses; (f) determining virtual speaker angles alpha' and beta' relative to listener position wherein said virtual speaker angles are computed using a virtual stereo speaker spacing and listener position; (g) determining virtual inter-aural delays between the virtual speakers and the listeners ears for virtual speaker angles alpha' and beta' relative to listener position; (h) determining virtual headshadow responses associated with each ear relative to each of the virtual speakers given the virtual speaker angles and; (i) determining a virtual speaker to listener transfer function H desired representing the transfer functions between the virtual speakers and the listener ears; and (j) computing two pairs of stereo expansion filters as a function of the actual speaker to listener transfer function H and the virtual speaker to listener transfer function H desired ; and wherein the listener is centered on the actual speakers, and the method further including: (k) transforming the two pairs of filters to a single pair of filters RES(1,1) and RES(2,2) to transform a lattice form to a shuffler form; (l) variable octave complex smoothing the pair of filters RES(1,1) and RES(2,2) to obtain smoothed filters sRES(1,1) and sRES(2,2) to preserve audio quality and spatial widening; and (m) transforming the pair of filters sRES(1,1) and sRES(2,2) back into lattice form for performing spatialization and preserving the audio quality.