3D printed acoustic metamaterials with microscale gaps as sound-absorbing mask for the patients of Tourette syndrome

Tourette syndrome (TS) is an inherited neurophysiologic disorder with onset in childhood, characterized by multiple physical (motor) tics and at least one vocal (phonic) tic. Patients with TS constantly feel immense anxiety in public due to the issues of vocal tics or coprolalia. Therefore, this study aims to design a specialized mask for TS patients to reduce the intensity of vocal tic or coprolalia such that the quality of life can be greatly improved. The paper presents a novel concept of sound absorption using 3d-printed acoustic metamaterials (AMs) with microscale gaps as the impedance-matched surface and experimental study on sound transmission loss. A simple construction based on the acoustically impedance matched surface embedded with asymmetric metallic platelets, hybrid resonances with high energy dissipation can be confined and absorb low-frequency airborne sound in frequencies ranging from 10 to 1300 Hz. The octave band analysis on the samples sound suppression capability is discussed. The field test results revealed an effective sound suppression capability can be fulfilled in the range of 89–94% for the frequency range 10–1300 Hz. The sound absorption performances of customized mask are shown to be effective and the prototypes had been clinically tested on the patients of TS. An alternative low-cost, impedance-matched AMs structure for the patients of TS is successfully developed.