  Sound in indoor spaces forms a complex wavefield due to multiple scattering
encountered by the sound. Indoor acoustic communication involving multiple
sources and receivers thus inevitably suffers from cross-talks. Here, we
demonstrate the isolation of acoustic communication channels in a room by
wavefield shaping using acoustic reconfigurable metasurfaces (ARMs) controlled
by optimization protocols based on communication theories. The ARMs have 200
electrically switchable units, each selectively offering 0 or {\pi} phase
shifts in the reflected waves. The sound field is reshaped for maximal Shannon
capacity and minimal cross-talk simultaneously. We demonstrate diverse acoustic
functionalities over a spectrum much larger than the coherence bandwidth of the
room, including multi-channel, multi-spectral channel isolations, and
frequency-multiplexed acoustic communication. Our work shows that wavefield
shaping in complex media can offer new strategies for future acoustic
engineering.
