Transmission loss of a labyrinthine acoustic metamaterial augmented with multichannel feedforward active noise control

<p dir="ltr">Acoustic metamaterials and active noise control are two advanced noise control treatments that can typically offer performance that exceeds that of conventional passive noise control treatments. Acoustic metamaterials utilize sub-wavelength structures to realize sound field control, whilst active noise control treatments achieve control via the introduction of additional acoustic sources driven to generate a secondary sound field that interferes in a controlled way with the original, primary sound field. This paper presents an investigation into combining these two noise control techniques to achieve enhanced noise control over a spatial region using a “hybrid” device. In particular, conventional feedforward active noise control is combined with a labyrinthine metasurface and the increase in performance offered by the hybrid solution is demonstrated.</p>