Yeah, but you're suggesting using voice recognition software to diagnose a suspected problem with audio hardware. That's daft. Listen to the audio. If it's intermittently cutting out, or crackling in response to plosives, or slightly distorted, or full of 50Hz mains hum or whatever, that'll tell you it's a microphone problem. If the audio sounds good, then you know it's something else affecting the voice recognition performance and you can look elsewhere.