In this paper the correction of the degradation of the stereophonic
illusion due to off-centre listening is investigated. The main idea here is
that the directivity pattern of a loudspeaker array should have a well
defined shape such that a good stereo sound reproduction is achieved in
a large listening area. Optimal digital filters are designed and applied to
individual drivers of linear loudspeaker arrays in order to obtain a directivity
pattern of a specific shape. This shape is adapted to the time/intensity trading
mechanism of the human auditory system via psychoacoustic experiments
within a wide listening area. This application is also referred to as
``Position Independent (PI) Stereo''.