Systems and methods for utilizing inter-
microphone level differences (ILD) to attenuate
noise and enhance speech are provided. In exemplary embodiments, primary and secondary acoustic signals are received by omni-directional microphones, and converted into primary and secondary electric signals. A differential
microphone array module processes the electric signals to determine a cardioid primary
signal and a cardioid secondary
signal. The cardioid signals are filtered through a
frequency analysis module which takes the signals and mimics a
cochlea implementation (i.e., cochlear domain). Energy levels of the signals are then computed, and the results are processed by an ILD module using a non-linear combination to obtain the ILD. In exemplary embodiments, the non-linear combination comprises dividing the
energy level associated with the primary
microphone by the
energy level associated with the secondary microphone. The ILD is utilized by a
noise reduction
system to enhance the speech of the primary acoustic
signal.