Mathematical modeling of acoustical systems is a popular design tool. To verify math models for acoustical systems of small physical size, probe‐tube microphones are often used. Unfortunately, the presence of the probe tube, itself, sometimes affects the sound field being measured. One way to solve the problem is to account for this effect by incorporating a model of the probe tube into an overall math model of the entire system. Equations for analyzing sound transmission through probe tubes are not available in most contemporary acoustics textbooks. This paper describes a method for mathematically modeling the acoustical characteristics of probe‐tube microphones using equations developed in 1950 for application to transient fluid flow in pipes. The accuracy of the method is demonstrated by mathematically simulating a probe‐tube calibration experiment in the laboratory. The experimental data and data derived from the math model agree quite well over the frequency range from 10 to 10 000 Hz. This shows that the math model of the probe‐tube microphone used in this experiment was correct. The result also suggests that this model may be included in an overall system model, given that several restrictions listed in this paper are closely followed.