Wave-domain loudspeaker signal decorrelation for system identification in multichannel audio reproduction scenarios

For applications like acoustic echo cancellation (AEC) or listening room equalization (LRE), a loudspeaker-enclosure-microphone system (LEMS) must be identified. When using a large number of reproduction channels, as, e. g., for wave field synthesis (WFS) or Higher-Order Ambisonics (HOA), the strong correlation of the loud-speaker signals will hamper a unique identification. A state-of-the-art remedy against this so-called nonuniqueness problem is a decorrelation of the loudspeaker signals, which facilitates a unique identification. However, most of the known approaches are not suitable for acoustic wave field reproduction schemes, as they would distort the reproduced wave field in an uncontrolled manner or degrade the audio quality. In this contribution, we propose a wave-domain time-varying filtering of the loudspeaker signals, so that the reproduced wave field is rotated within a perceptually acceptable range, while preserving its shape.