How do you ensure that, in a reverberant room, several people can speak simultaneously to several other people, making themselves perfectly understood and without any crosstalk between messages? In this work, we report a conceptual solution to this problem by developing an intelligent acoustic wall, which can be reconfigured electronically and is controlled by a learning algorithm that adapts to the geometry of the room and the positions of sources and receivers. To this end, a portion of the room boundaries is covered with a smart mirror made of a broadband acoustic reconfigurable metasurface (ARMs) designed to provide a two-state (0 or {\pi}) phase shift in the reflected waves by 200 independently tunable units. The whole phase pattern is optimized to maximize the Shannon capacity while minimizing crosstalk between the different sources and receivers. We demonstrate the control of multi-spectral sound fields covering a spectrum much larger than the coherence bandwidth of the room for diverse striking functionalities, including crosstalk-free acoustic communication, frequency-multiplexed communications, and multi-user communications. An experiment conducted with two music sources for two different people demonstrates a crosstalk-free simultaneous music playback. Our work opens new routes for the control of sound waves in complex media and for a new generation of acoustic devices.

翻译：如何确保在一个混响房间内，多人可以同时与另外多人交谈，且彼此完全理解且信息之间无串扰？本文针对这一问题提出了一种概念性解决方案：开发一种可通过电子方式重构的智能声学墙壁，该墙壁由学习算法控制，能够自适应于房间的几何形状以及声源和接收器的位置。为此，房间边界的部分区域覆盖了一种由宽带声学可重构超表面（ARMs）制成的智能反射镜，该超表面通过200个独立可调单元为反射波提供两种状态（0或π）的相位偏移。整个相位模式经过优化，以最大化香农容量并最小化不同声源与接收器之间的串扰。我们展示了覆盖远大于房间相干带宽频谱的多光谱声场控制能力，实现了无串扰声学通信、频分复用通信以及多用户通信等多种显著功能。一项针对两位不同用户的两个音乐源的实验展示了无串扰的同时音乐播放。我们的工作为复杂介质中声波的控制以及新一代声学器件的开发开辟了新路径。