1. A process of operating a sound recognition sensor comprising: (a) receiving analog sound signals in signal trigger logic that is maintained in a powered up active mode while maintaining other circuitry of the sensor in a low power mode; (b) powering up normally powered down parallel analog channels of the sensor in response to a first trigger signal indicating the signal trigger logic receiving analog sound signals greater than a reference; (c) extracting a first frame based sparse feature from the received analog sound signals in one analog channel; (d) extracting a second frame based sparse feature, different from the first frame based sparse feature, from the received analog sound signals in a another analog channel simultaneously with the extracting a first frame based sparse feature; (e) producing an event trigger signal from event trigger logic in response to at least one of the extracted features from the channels indicating a starting point; (f) powering up normally powered down classifier circuitry in response to the event trigger signal; and (g) performing sound recognition on the received sound signals in the classifier circuitry based on the received analog sound signals.
3. The process of claim 1 in which the extracting the sparse sound features includes extracting one of zero crossing information, total energy values, band pass energy values, high pass energy values, or low pass energy values in each analog channel.