Noise attenuation

摘要

Noise attenuation apparatus comprising an enclosure having a wall separating an interior and an exterior. The enclosure defines a volume. The volume is characterized by an acoustic compliance and includes a device producing noise. The noise has spectral components predominantly in a noise frequency range. A first port has a first acoustic mass. The port passes through the wall between the interior and the exterior wherein the acoustic compliance and the first acoustic mass are configured to establish a resonant frequency outside the noise frequency range. <IMAGE>