It is able to highlight details human eyes cannot normally see, either because they are swamped by the signal from other visible frequencies, or because they are notdetectable by the rod and cone cells of the retina.
The result is a vehicle sound at low speeds (up to about 17 miles per hour), that was designed to be very detectable around the vehicle but not take away from the quietness of the interior of the vehicle.
That energy depletion would have resulted in a spectral distortion detectable by OPERA. However, the OPERA data did not show either the energy depletion or the spectral shift.