Noise and vibration generated by the cooling fans, disc drives and power supplies.
The fundamental sources and mechanisms are:
- Fans - there are a number of fans in a computer, used to cool the case, the power supply and the processor.
- Aerodynamic airflow over the blades can generate noise
- Objects placed in front of and behind the fan can generate a turbulent airflow and hence noise.
- One simple option is to increase the size of the fan and reduce the speed.
- The motor and fan blade may run out of balance and the vibration will get transmitted through the case.
- Disc drives - motor noise and any out of balance can be transmitted into the case structure and then get radiated. This may be solved:
- Isolate the drives from the structure of the case.
- Use solid state hard drives
- Add damping to the structure of the case.
- Apply damping pads to the large unsupported surfaces of the case to reduce their applitude of vibration to inputs such as disc drive or fan vibration.
- Add acosutic treatment to the case to absorb airborne noise from fans.
- Create a tortuous and acoustic lined path to airflow in and out of the case.
ANSI S12.10 Measurement and Designation of Noise Emitted by Computer and Business Equipment
ISO 7779 Measurement of Airborne Noise Emitted by Computer and Business Equipment
See also: Fan Noise.