Optimization of Wavelet Packets to Minimize the Effect of Spectral Masking for Improving Speech Perception

Spectral masking occurs when the perception of one sound is affected by the presence of another sound like noise or unwanted sound of the same duration as the original sound. Earlier studies have shown that binaural dichotic presentation, using a pair of linear phase FIR comb filters with complementary magnitude responses, helps in reducing the effect of spectral masking. In the present study a spectral splitting of speech signals is done by using improved wavelet packets that provides a pair of bands of pre-recorded speech signals, which are presented dichotically that is odd bands of frequencies are given to the right ear and even bands to the left ear simultaneously. The performance of the proposed method is experimentally evaluated with speech signals of vowel-consonant-vowel syllables for twenty one English consonants. The result of Qualitative assessment, Response time and Recognition scores obtained after conducting listening tests on the five subjects, shows the effectiveness of method of improved wavelet packets over the comb filter. General Terms Signal Processing, Wavelet Representations et. al.