Improvement in Listener Comfort Through Noise Shaping Using a Modified Wiener Filter Approach

The Wiener filter approach to noise suppression is well known both theoretically and practically. This paper explains the idea of extending this filtering approach to shape the residual noise of the output signal. Motivated by different kinds of stationary and instationary noise sources that appear in an automobile, along with the necessity to address the problem of increasing the listener comfort, an algorithm to achieve a time-frequency varying attenuation in the lower frequencies has been developed. The basic theory and the conditions to achieve this are presented. Details of the developed compressor algorithm as well as the modifications necessary to apply it to the classical Wiener filter are shown. The improvement that the modified filter brings to the noise input signal are significant and analyses of the results clearly show a reduction of the "ruggedness" of the input signal.