Abstract: The theory for a very simple procedure that can be used to measure the specific acoustic impedance of any termination of an acoustic transmission tube is described. The virtues of this method are that there are no moving parts and there is no need to calibrate the transfer properties of a microphone and coupling. The only precision measurements concern the frequency and the location of two holes necessary for the detection of pressure in the tube. The holes are located equidistantly from the center of the tube. A source is affixed to one end and the termination to the other. Frequency is adjusted until a relative minimum in the standing-wave pattern appears at the microphone closer to the termination. The voltage from each microphone is recorded. Then the source and termination are interchanged while the microphones are left undisturbed. The above process is repeated. The product of the voltage ratios is the same as the square of the pressure ratio. With this information, it is possible to calculate without too much difficulty the specific acoustic impedance of the termination.