Active Noise Control Systems

Researchers at ANU have developed integrated active noise control (ANC) solutions for complex noise problems and are designing cost-effective, practical ANC systems for cockpits, homes, office space, and car cabins.

Background

Active noise control (ANC) quiets offensive noise by using cancellation techniques or anti-sound. ANC systems use microphones, speakers and a controller (computerised control unit with inbuilt algorithms) to transmit an anti-noise soundfield that negates the unwanted soundfield. Designing an effective ANC system is not a simple process and the performance of that system depends on a number parameters such as microphone and speaker arrangement (number and location), controller algorithm complexity and soundfield signal qualities. In airplanes and automobiles the process is even more complicated as preferred microphone and/or speaker locations for ideal noise reduction may be unavailable due to the positioning of interior trim panels, internal structures and system mechanisms. Whilst progress has been made towards producing quieter airplanes and automobiles, pilots are still exposed to noise levels that can have lasting health consequences (e.g. noise induced hearing loss), plus unwanted engine and road noise can increase driver drowsiness and interfere with in-cabin conversations.

Opportunity

Researchers from ANU have established key technologies and know-how that enables more adaptive control of noise cancellation over space. Using a recently developed (patent pending) flat-plane microphone array (with full 3D sound capture capability) and custom-designed digital signal processing algorithms (utilising source-to-region acoustic transfer function) ANU researchers are fabricating cockpit and car cabin ANC systems that are simpler (requiring a smaller number of components), integrable, more cost-effective, capable of enhanced noise reduction, and adaptable (customisable to specific applications and noise environments).This technology could also be applied to ANC systems for ship bridges, heavy machinery operator cabins, rail crew cabs, surgery and patient rooms, restaurants and hotel lobbies, nurseries and classrooms, and more.