In this paper we study the influence of the sub-band adaptive filtering speech enhancement method on speech recognition systems in multi-source noisy environment using a speaker and a noise reference microphone. In extensive experiments, the recognition score of a speaker independent isolated word speech recognition system based on a continuous density HMM (CDHMM) has been measured in the presence of real life noises in various SNRs. In all experiments the results show improvement in the mean recognition score when the sub-band adaptive filtering LMS method is used in comparison to the full-band LMS method. This improvement increases when changing types of noise distort the speech signal.