A group of devices acquire audio input of a sound, such as speech, using respective microphones. For pairs of devices in the group, intensity of energy of audio input at each of the devices in the pair is used to determine first proximity data. Relative differences in time-of-arrival of the sound at the devices in the pair is used to determine second proximity data. The first and second proximity data are used to determine an estimated closest device of the pair with respect to the sound. Comparison of the first proximity data to the second proximity also allows a confidence value to be associated with the estimated closest device. The estimated closest device with the greatest confidence value may be selected for use to acquire audio input, present output, and so forth. Additional techniques such as beamforming techniques may be applied to the audio input from the selected device.