US Patent 11158335 Audio beam selection

A voice-controlled device includes a beamformer for determining audio data corresponding to one or more directions and a beam selector for selecting in which direction a source of target audio lies. The device determines magnitude spectrums for each beam and for each frequency bin in each beam for each frame of audio data. The device determines frame-by-frame changes in the magnitude and filters the changes to smooth them. The device selects the beam having the greatest smoothed change in magnitude as corresponding to speech.