The tree cricket ear is a highly phase sensitive biomechanical interferometer.

We show that tree crickets localize the sound by having an auditory system that first splits the soundwave into two parts, sending one wave to an Anterior tympanic membrane, and sending the second to a Posterior tympanic membrane. The membranes then carry the split waves to a common point, the Tracheal wall, where the re-assembly of the wave causes mechanical interference that is sensitive to microsecond time delays. This interference mechanically transduces the time delay into a simple lateral strain at the Tracheal wall. This principle, interferometry, is usually thought of in terms of light (Michaelson and Morley, 1887), and can measure extremely small time-delays. Tree crickets use the same principle as the light interferometer, except with sound, to measure extremely precise locations.