A device, system, and method whereby a speech-driven system used in an industrial environment distinguishes speech obtained from users of the system from other background sounds. In one aspect, the present system and method provides for a first audio stream from a user microphone collocated with a source of human speech (that is, a user) and a second audio stream from a environmental microphone which is proximate to the source of human speech but more remote than the user microphone. The audio signals from the two microphones are asynchronous. A processor is configured to identify a common, distinctive sound event in the environment, such as an impulse sound or a periodic sound signal. Based on the common sound event, the processor provides for synchronization of the two audio signals. In another aspect, the present system and method provides for a determination of whether or not the sound received at the user microphone is suitable for identification of words in a human voice, based on a comparison of sound elements in the first audio stream and the second audio stream, for example based on a comparison of the sound intensities of the sound elements in the audio streams.