The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed
proximate to a
server, without substantially obstructing
airflow from the
server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific
resonance frequency, and includes a neck portion and
air chamber dimensioned to resonate at the desired
resonance frequency and thereby inverse phase cancel corresponding
narrowband frequencies of incoming sound
waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the
server's fan(s), with an opening in the frame structure to facilitate
airflow therethrough, without obstructing or substantially obstructing the
airflow to the surrounding environment.