Patent ID: 8756055

Claim:
A method for enhancing speech output by an electro-acoustical transducer in a noisy listening environment, comprising: filtering an input audio signal x(t) using an adaptable filter H(z) to produce a filtered audio signal x (t); providing the electro-acoustical transducer an analog signal corresponding to the filtered audio signal to produce a sound wave corresponding to the filtered audio signal; and prior to filtering the audio signal using the filter, configuring the filter such that, with respect to one or more frequencies ƒ, the filtered audio signal has a higher signal level than the input audio signal, and such that the overall signal level of the filtered audio signal sl f relates to the overall signal level of the input signal sl r such that sl f =sl f ×c, where c comprises a constant, wherein the step of configuring the filter comprises: estimating, based on at least a portion of the input audio signal, a signal spectrum P x (ƒ); and estimating, based on at least a portion of an audio signal corresponding to a signal received by an acoustic-electronic transducer, a noise spectrum P y (ƒ), and for each of the one or more frequencies ƒ, determining a gain function γ(ƒ) for the filter based on the estimated spectra P X (ƒ) and P y (ƒ), wherein determining the gain function comprises: for each of the one or more frequencies ƒ, determining SNR(ƒ) based on P x (ƒ) and P y (ƒ) and determining the gain function based on γ ER (ƒ), wherein, for ƒ<ƒ T , γ ER (ƒ)=min(1,max(c1, SNR(ƒ)/c2)), wherein ƒ T , c1, and c2 comprise predetermined values.