Apparatus for investigating wave phenomena using sound. The efficient transducers may be driven by the output from a standard audio signal generator, and their sensitivity as receivers is such that they may be used directly on the 5mV input of an oscilloscope. Detailed equipment notes are provided covering investigations into: reflection and refraction; interference patterns in air; detection and measurement of phase differences in a signal received by two receivers; measurement of wavelength using the phase difference between transmitter and receiver etc. Units are housed in boxes (100mm x 75mm x 40mm) and the set comprises three transducers and one control box as follows: Transducers may be used as either transmitters or receivers. Electrical connection via 2m screened lead with 4mm plugs. Control box having 1m of screened input lead with 4mm plugs, & two pairs of 4mm output sockets. Switch permits phase reversal between the two outputs.
