Implementation of a real-time feedback active noise control system to cancel noise within a 3-dimensional enclosure

This paper presents analysis and design of a real time active noise control system for cancelling the acoustic noise generated by an HVAC (Heating Ventilation and Air-Conditioning) unit within a 3-dimensional enclosure. The system described in this paper is a single channel system using a feedback ANC architecture. We will test the viability of this system using both synthetic tonal noise generated from a secondary speaker and real noise generated by a commercially available 5-ton HVAC unit placed inside a medium size closet. The system proposed in this paper is capable of achieving over 10 decibels of attenuation of the HVAC noise and more than 40 decibels of attenuation of tonal noise. Using secondary microphones located outside the closet we show that our system is capable of achieving a reduction in the noise level outside the closet for low frequency tonal noise.