Providing Spatial Control in Personal Sound Zones Using Graph Signal Processing

[EN] Personal audio systems aim to create listening (or bright) and quiet (or dark) zones in a room using an array of loudspeakers. For this purpose, many algorithms have been presented in the literature, being Weighted Pressure Matching (wPM) one of the most versatile. The main strength of wPM is that it can render a target soundfield in the listening zone while having control over the mean acoustic potential energy in the quiet zone. In this paper, we propose a variation of wPM such that it can provide control not only over the mean energy, but also over the spatial energy differences, obtaining a more uniform soundfield in the dark zone. The new algorithm is called wPM with Total Variation (wPM-TV), where TV is a tool used in the field of Graph Signal Processing (GSP). Firstly, we propose a graph representation of the control microphones of the dark zone and secondly, we use the wPM-TV algorithm to provide spatial control over that zone. Simulations show the good performance of the proposed algorithm and its versatility to obtain a more uniform distribution of the acoustic potential energy in the dark zone at the cost of slightly increasing the mean square reproduction error in the bright zone.This work has been partially supported by Spanish Ministry of Science, Innovation and Universities through grant FPU17/01288 and by European Union together with Spanish Government through grant RTI2018-098085-BC41 (MCIU/AEI/FEDER)Molés-Cases, V.; Piñero, G.; Gonzalez, A.; Diego Antón, MD. (2019). Providing Spatial Control in Personal Sound Zones Using Graph Signal Processing. IEEE. 1-7. https://doi.org/10.23919/EUSIPCO.2019.8903068S1

Personal Sound Zones by Subband Filtering and Time Domain Optimization

[EN] Personal Sound Zones (PSZ) systems aim to render independent sound signals to multiple listeners within a room by using arrays of loudspeakers. One of the algorithms used to provide PSZ is Weighted Pressure Matching (wPM), which computes the filters required to render a desired response in the listening zones while reducing the acoustic energy arriving to the quiet zones. This algorithm can be formulated in time and frequency domains. In general, the time-domain formulation (wPM-TD) can obtain good performance with shorter filters and delays than the frequency-domain formulation (wPM-FD). However, wPM-TD requires higher computation for obtaining the optimal filters. In this article, we propose a novel approach to the wPM algorithm named Weighted Pressure Matching with Subband Decomposition (wPMSD), which formulates an independent time-domain optimization problem for each of the subbands of a Generalized Discrete Fourier Transform (GDFT) filter bank. Solving the optimization independently for each subband has two main advantages: 1) lower computational complexity than wPM-TD to compute the optimal filters; 2) higher versatility than the classic wPM algorithms, as it allows different configurations (sets of loudspeakers, filter lengths, etc.) in each subband. Moreover, filtering the input signals with a GDFT filter bank (as in wPM-SD) requires lower computational effort than broadband filtering (as in wPM-TD and wPM-FD), which is beneficial for practical PSZ systems. We present experimental evaluations showing that wPM-SD offers very similar performance to wPM-TD. In addition, two cases where the versatility of wPM-SD is beneficial for a PSZ system are presented and experimentally validated.This work was supported by Grants RTI2018-098085-B-C41 (MCIU/AEI/FEDER, UE), RED2018-102668-T and PROMETEO/2019/109. The work of Vicent Moles-Cases has been supported by Spanish Ministry of Education under Grant FPU17/01288.Molés-Cases, V.; Piñero, G.; Diego Antón, MD.; Gonzalez, A. (2020). Personal Sound Zones by Subband Filtering and Time Domain Optimization. IEEE/ACM Transactions on Audio Speech and Language Processing. 28:2684-2696. https://doi.org/10.1109/TASLP.2020.3023628S268426962

A Weighted Least Squares Beam Shaping Technique for Sound Field Control

reserved7A weighted least squares beam shaping technique for sound field control using a loudspeaker array is proposed. Given a desired spatial response at prescribed control points, the space-time filter is designed by solving a least squares minimization problem. To reduce the computational effort, we propose to place control points only along an arc of circumference centered at the center of the array and passing through a region of interest. Furthermore, we adopt a weighted least squares approach for the design of the space-time filter, so that control points at directions towards which we admit a looser control of the sound field are less relevant in the filter design. The choice of the weights depends on the specific application and we demonstrate the feasibility of the proposed approach for sound zones scenario with one bright and one dark zone.mixedCanclini A.; Markovic D.; Schneider M.; Antonacci F.; Habets E.A.P.; Walther A.; Sarti A.Canclini, A.; Markovic, D.; Schneider, M.; Antonacci, F.; Habets, E. A. P.; Walther, A.; Sarti, A