The whole system for noise suppression in speech recorded in a running car was designed. One channel spectral subtraction method with full-wave rectification was chosen because of its robustness, simplicity, and non-musical tone output. The improvement of noise suppression was gained by the repetition of this method. Directional microphones for the signal picking up were chosen to improve the input signal-to-noise ratio (SNR) of corrupted speech signal. Segment speech/pause detector based on energy tracking was used with some prefiltration of corrupted speech to improve detector function.

Keywords: noise suppression, speech enhancement, spectral subtraction, musical tones, speech/pause detection