A typical cardioid microphone, like an ear, hears best from the front, but its readings blur when sound comes from the side. The solution is to gather several such 'ears' into a sphere. You get a sound ball that picks up signals from all directions. By comparing measurements, the system breaks down errors into simple components — much like spectroscopy splits light. Then it filters out noise using the same mathematical trick as gravitational wave detectors. Amazingly, this scheme works great even when microphones are spaced a meter or two apart — something that used to throw off the bearing for sure. In the end, the signal is cleaned up, like a telescope image cleared of cosmic dust, and previously invisible errors, like dark matter, no longer distort the picture.