Publication Details

J. Donley, C. Ritz & W. Bastiaan. Kleijn, "Multizone Soundfield Reproduction With Privacy- and Quality-Based Speech Masking Filters," IEEE ACM Transactions on Audio, Speech, and Language Processing, vol. 26, (6) pp. 1041-1055, 2018.


Reproducing zones of personal sound is a challenging signal processing problem which has garnered considerable research interest in recent years. We introduce in this work an extended method to multizone soundfield reproduction which overcomes issues with speech privacy and quality. Measures of Speech Intelligibility Contrast (SIC) and speech quality are used as cost functions in an optimisation of speech privacy and quality. Novel spatial and (temporal) frequency domain speech masker filter designs are proposed to accompany the optimisation process. Spatial masking filters are designed using multizone soundfield algorithms which are dependent on the target speech multizone reproduction. Combinations of estimates of acoustic contrast and long term average speech spectra are proposed to provide equal masking influence on speech privacy and quality. Spatial aliasing specific to multizone soundfield reproduction geometry is further considered in analytically derived low-pass filters. Simulated and real-world experiments are conducted to verify the performance of the proposed method using semi-circular and linear loudspeaker arrays. Simulated implementations of the proposed method show that significant speech intelligibility contrast and speech quality is achievable between zones. A range of Perceptual Evaluation of Speech Quality (PESQ) Mean Opinion Scores (MOS) that indicate good quality are obtained while at the same time providing confidential privacy as indicated by SIC. The simulations also show that the method is robust to variations in the speech, virtual source location, array geometry and number of loudspeakers. Real-world experiments confirm the practicality of the proposed methods by showing that good quality and confidential privacy are achievable.



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