Comparison of two methods for measurement of horn input impedance

Two methods to measure the acoustic input impedance of a horn are compared. The first method measures standing-wave patterns in a tube which is loaded by the horn. The input impedance is calculated from the position of the first minimum in the standing-wave pattern and the ratio of maximum to minimum sound pressure levels in the tube. Second a direct method was applied. A novel flow sensor, the microflown, is used together with a pressure microphone, which are mounted in the throat of the horn. Results from both measurements are compared with simulated models.