Abstract: The present invention relates to methods and devices for processing one or the other of two types of common input audio stereo signals so that the output signals will reproduce normally wide stereo sound from an audio stereo reproduction system comprising a pair of identical loudspeakers positioned adjacent or close to each other. Thus, the invention relates partly to a method and a device for producing that specific pair of left and right output signals from one kind (M+S) of input signals, and partly to a method and a device for producing a similar type of left and right output signals from another kind (L+R) of input signals. Finally, the invention relates to an audio stereo signal reproduction system comprising a pair of identical louspeakers positioned adjacent or close to each other and intended for reproduction of normally wide stereo sound from one (M+S) of said kinds of input signals.

Abstract: A method of processing and reproducing an input audio stereo signal in an audio signal processing system comprises the steps of (1) splitting a side signal into a first and a second intermediate signal, where the first intermediate signal is equal to the side signal and the second intermediate signal is equal to the first intermediate signal phase shifted 180°, (2) attenuating the mid signal by a factor a which compensates for imperfections in the balance between the mid and side signals appearing in the audio reproduction stage, (3) adding the attenuated mid signal to both of the first and second intermediate signals, so as to form the output audio stereo signal, and (4) directing the output stereo signal to an audio stereo signal reproduction system, comprising a pair of loudspeaker units located in close proximity to each other.