For high-quality multimedia communication systems such as telecollaboration or virtual reality applications, both multichannel sound reproduction and full-duplex capability are highly desirable. Full 3D sound spatialization over a large listening area is offered by wave field synthesis, where arrays of loudspeakers generate a prespecified sound field. However, before this new technique can be utilized for full-duplex systems with microphone arrays and loudspeaker arrays, an efficient solution to the problem of multichannel acoustic echo cancellation (MC AEC) has to be found in order to avoid acoustic feedback. This paper presents a novel approach that extends the current state of the art of MC AEC and transform-domain adaptive filtering by reconciling the flexibility of adaptive filtering and the underlying physics of acoustic waves in a systematic and efficient way. Our new framework of wave-domain adaptive filtering (WDAF) explicitly takes into account the spatial dimensions of loudspeaker arrays and microphone arrays with closely spaced transducers. Experimental results with a 48-channel AEC verify the concept for both, simulated and measured room acoustics.
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