epresentation of speech signal has shown to be attractive for noisy speech recognition because of both its high recognition performance with respect to the conventional LP in severe conditions of additive broad-band noise and its computational simplicity. However, the mel-cepstrum representation, which comes from a filter bank (FB) analysis, has become increasingly popular. Furthermore, hybrid techniques that combine filter-bank and LP analysis, have also been proposed. The aim of this paper is to gain some perspective of the merit of the autocorrelation, LPand FB based techniques in a real environment.