Abstract: A housing for an aero-acoustic processing machine having rotational drive apparatus coupled to rotate an air impeller to draw air and material to be processed through an axial inlet system and expel the air and processed material through a transverse outlet. The housing includes an enclosure incorporating at least one layer of noise attenuation materials surrounding the aero-acoustic processing machine, the enclosure having a material inlet port, an air inlet port and an exhaust port for outputting processed product with air. Airflow paths that are required for operation of the aero-acoustic processing machine are provided to enable airflow into the housing whilst significantly reducing noise emission.