1. A speech recognition system comprising: a microphone; a first low power audio channel coupled to the microphone; a second audio channel coupled to the microphone; and a processor having signal lines coupled to the first and second audio channels, wherein the processor turns on the first low power audio channel and turns off the second audio channel during a low power mode of operation, and the processor turns on the second audio channel when the first low power audio channel receives an input signal above a first threshold.