Direction-aware active noise cancellation system

A system for reducing an acoustic energy level at a listening position, the system comprising:

• a first reference microphone for receiving a primary acoustic wave at a first reference position to form a first reference signal, receiving the primary acoustic wave comprising converting the primary acoustic wave to a frequency-domain such that the first reference signal is separated into sub-bands in the frequency domain;
• a second reference microphone for receiving the primary acoustic wave at a second reference position to form a second reference signal, receiving the primary acoustic wave comprising converting the primary acoustic wave to a frequency-domain such that the second reference signal is separated into sub-bands in the frequency domain;
• a feedforward module for determining, in the frequency domain, a direction of propagation of the primary acoustic wave for each sub-band of the first reference signal and each sub-band of the second reference signal based on the first and second reference signals, and to form, in the frequency domain, a feedforward sub-band signal based on the determined direction of propagation of the primary acoustic wave;
• and
• an audio transducer for generating a secondary acoustic wave based on the feedforward sub-band signal, the secondary acoustic wave adapted to reduce the acoustic energy level at the listening position.

A non-transitory computer readable storage medium having embodied thereon a program, the program being executable by a processor to perform a method for reducing an acoustic energy level at a listening position, the method comprising:

• receiving a primary acoustic wave at a first reference position to form a first reference signal;
• receiving the primary acoustic wave at a second reference position to form a second reference signal;
• separating each of the first reference signal and the second reference signal into a plurality of sub-band signals in the frequency domain;
• determining, in the frequency domain, a direction of propagation of the primary acoustic wave for each sub-band of the first reference signal and each sub-band of the second reference signal based on the first and second reference signals;
• forming, in the frequency domain, a feedforward sub-band signal based on the determined direction of propagation of the primary acoustic wave;
• and
• generating a secondary acoustic wave based on the feedforward sub-band signal, the secondary acoustic wave adapted to reduce the acoustic energy level at the listening position.