A single dual-fan ASIC running at 6,000 RPM generates between 75 and 82 dBA of high-frequency whine—comparable to standing next to a commercial vacuum cleaner or running lawnmower. For operators in rural-residential zones or shared workshop units, this noise level violates local EPA environmental noise guidelines.
Our test bench lab in Cowwarr evaluated four enclosure geometries to balance acoustic attenuation against static airflow resistance. Simple straight-through boxes with foam lining only achieved a modest 9 dB reduction because high-frequency sound waves travel in line-of-sight.
By designing a serpentine S-curve internal baffle lined with 75mm high-density mineral wool (Rockwool Safe'n'Sound, 60kg/m³ density) and an internal acoustic septum plate, sound waves are forced to bounce off sound-absorbing surfaces three times before exiting. This geometry yielded an astonishing 28 dBA reduction, bringing ambient operational sound to 49 dBA at 3 metres—equivalent to a quiet conversation.
Crucially, the cross-sectional intake area was expanded to 350mm x 350mm to keep air velocity below 2.5 metres per second, preventing aerodynamic turbulence noise. This article provides complete dimensional drawings and material cut lists for constructing your own dual-machine sound enclosure.