Patent ID: 7558390

Claim:
A method of equalizing output signals from a first and a second microphones, the method comprising the steps of: generating a first predictable noise; converting the first predictable noise to an audio output using a first converter having a known transfer function; receiving the audio output at the first microphone and converting the audio output to a first output noise; generating a second predictable noise; synchronizing the first predictable noise and the second predictable noise in time by a synchronizer; compensating the second predictable noise for the known transfer function by a compensation filter; outputting a second output noise by the compensating filter; determining coefficients representing a first transfer function of the first microphone based on the first and second output noises determining coefficients for a first filtering function for the first microphone, based on a single selected function for the first and second microphones and the coefficients representing the first transfer function, wherein a first product of the first transfer function of the first microphone and the first filtering function is the single selected function, and wherein the single selected function equals a second product of a second transfer function of the second microphone and a second filtering function for the second microphone; and providing the coefficients for the first filtering function to an equalization filter for filtering an output from the first microphone.