How does quality of microphone affect speech recognition?

Question

Most sites I've been to clearly say that for speech recognition, higher quality of microphones lead to better results. I have been surfing around for more details, like how do things like the following affect speech recognition -

• Sensitivity
• SNR
• Frequency Responce
• Output Impedence

But I would like to know about how these affect speech in more detail. The SNR makes sense for noise cancellation, but I dont know much about the others.

Some websites that I have checked out -

http://www.acoustics.salford.ac.uk/acoustics_info/microphones/

http://www.speechrecsolutions.com/microphone_accuracy.htm

Answer 1

SNR is pretty important; often, just as important is a constant audio level, which is why close-talking microphones work so much better than desktop microphones. Frequency response is important, particularly a fairly flat response; a broad response (anything past 12 KHz) is less important. Output impedance isn't terribly important at all (assuming it's matched reasonably well to the audio input).