An Acoustic Intensity Meter

A device is described for measuring the intensity of an acoustic wave at a point. The instrument employs a crystal microphone as a pressure transducer, directional hot‐wire anemometer as a velocity transducer and an electronic multiplier and integrator. We can directly measure the intensity for any pressure or velocity wave form without having to assume any relationship between pressure and velocity. Several types of measurements have been made to indicate the present capabilities of the instrument.