Emphasis of short-duration transient speech features

(57) A summary microphone (1), a preamplifier (2), the parallel filter bank (3) that consists of N pieces, A means to detect changes of the short period of time in the envelope signal of each filter channel, And the sound processing unit which supports that the gain relates to the secondary differential coefficient of the envelope signal in each filter channel changed slowly, and perceives the feature of the sound of the short period of time of the low intensity in the inside of the above-mentioned signal including a means to add a gain to the output of these filter channels.