Steerable sound transport in a 3D acoustic network

Quasi-lossless and asymmetric sound transports, which are exceedingly desirable in various modern physical systems, are almost based on nonlinear or angular-momentum biasing effects with extremely high power levels and complex modulation schemes. A practical route for the steerable sound transport along any arbitrary acoustic pathway, especially in a 3D acoustic network, could revolutionize the sound power flow and the sound communication. Here, we design an acoustic device consisting of a regular-tetrahedral cavity with four cylindrical waveguides. A smaller regular-tetrahedral solid in this cavity is eccentrically emplaced to break its spatial symmetry. The numerical and experimental results show that the sound power flow can unimpededly transport between two waveguides away from the eccentric solid within a wide frequency range. Furthermore, in the vicinity of eigenmode, the sound waves from various waveguides can transport to different waveguides, respectively along the compressed and broadened pathways without mutually interference. Endowed with these quasi-lossless and asymmetric transport characteristics, we construct a 3D acoustic network, in which the sound power flow can flexibly propagate along arbitrary sound pathways defined by our acoustic devices with eccentrically-emplaced regular-tetrahedral solids.