The performance of ASR systems in a room environment with distant microphones is strongly affected by reverberation. As the degree of signal distortion varies among acoustic channels (i.e. microphones), the recognition accuracy can benefit from a proper channel selection. In this paper, we experimentally show that there exists a large margin for WER reduction by channel selection, and discuss several possible methods which do not require any a-priori classification. Moreover, by using a LVCSR task, a significant WER reduction is shown with a simple technique which uses a measure computed from the sub-band time envelope of the various microphone signals.