Single-ended spatial enhancement using a cross-coupled lattice equalizer

A stereophonic enhancement system is described which expands the perceived width of the stereo sound image. The system accepts electrical audio signals comprising a two-channel (left and right) stereo pair and produces enhanced left and right stereo signals for use with conventional two-channel audio recording and playback systems. The system includes control circuitry which monitors the dissimilarity of the left and right input signals and optionally the dissimilarity of the left and right processed output signals. An all-pass decorrelation subsystem can also be included for mono-to-stereo conversion of monophonic input signals prior to the spatial enhancement system.