Abstract: A microphone volume level controller, for use with a speech recognition system, sets a volume level of a microphone in response to measured environmental conditions. Parameters of an input signal generated by a microphone are measured at multiple microphone volume levels. Based on the measured parameters, a volume level is determined that compensates for environmental conditions. The microphone volume level is set to the determined volume level. Speech recognition system error conditions are detected by comparing input signal levels detected by a microphone at a lower volume level and a higher volume level. If the difference between the signal levels at the lower and higher signal levels falls below a predetermined threshold, the user is notified of a possible error condition.