Optimal microphone placement for active noise control in a forced- air cooling system

This paper discusses the placement of a microphone for feedforward based active noise control in a forced-air cooling system. Incorrect placement of microphones may lead to poor signal correlation that limit the ability of active noise suppression. Microphone placement can be by facilitated by direct on-line optimization of the Active Noise Control system. The feedforward based noise cancellation algorithm is applied to a data projector and uses the optimization results of a linearly parametrized filter to select microphone location. Successful implementation of the feedforward based active noise controller for this application shows a 20 till 40Db reduction of external noise over a broad frequency range from 1kHz till 5kHz.