US Patent 9820036 Speech processing of reflected sound

Sound is banked laterally over an array of microphones arranged on a rear surface of a device. Sound enters a duct behind the device from different directions via inlets along the sides of the device. The duct directs the sound waves across the microphone array. An effective direction from which the banked sounds originated is determined, relative to a front of the device. Based on the determined effective direction, the device applies spatial filtering to isolate the received sound waves, selectively increasing a signal-to-noise ratio of sound from the selected source and at least partially occluding sounds from other sources.