 João M. B. Lopes dos Santos

João M. B. Lopes dos Santos coauthored an inexpensive speed of sound experiment using two microphones and a computer's stereo sound input. A pulse reaches microphones at different distances at different times; dividing the path difference by the arrival-time difference estimates the propagation speed. Recording both channels together makes the relative delay directly accessible. The apparatus turns wave propagation into a quantitative measurement using familiar audio equipment.^[ref]