Stereo enhancement system

摘要

The sound field in a stereo reproduction system is enhanced by a preprocessor that removes a portion of the audio information that is common or substantially common to both the left and right stereo input signals before processing the signals in left and right sound placement filters. The left and right placement filter output signals, from which a portion of the common audio information was previously removed before processing, are added to the right and left stereo input signals, respectively, to produce enhanced sound field stereo output signals. The input signals that do not undergo placement processing are delayed in delay filters so that coherency is maintained when the signals are added and both the placement filters and the delay filters can be implemented by a series of cascaded bi-quadratic filters.