Smart speakers can be used to broadcast pulses in the 18-20 kHz range and calculate the position of people across the room by how the sound reflects off them. While the frequency can be heard by the human ear, it can be masked by music playing on the speakers. Researchers dubbed the attack CovertBand and claimed they have tested the proof-of-concept in five homes in the Seattle area, succeeding in tracking multiple people, even through barriers. The research proposes a couple of solutions for countering the attack, including sound-proofing and frequency-jamming.”]