Sound pickup for hands-free communications often requires the microphone to be located at a large distance from the talker. However, in typical environments, the resulting speech signal is corrupted by reverberation and noise which degrade perceived voice quality and impair the operation of automatic speech recognizers. Microphone arrays have been shown to provide substantial improvements in predicted voice quality in computer simulations. To measure microphone array performance in more realistic conditions, a flexible, experimental microphone array has been developed based on digital signal processing technology. This array is flexible enough to permit the implementation of a wide variety of signal processing strategies and array geometries. In this paper the array design will be described and the performance of this array in the variable-acoustics listening room at the National Research Council will be discussed.