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 radio of maximum and minimum sound-pressure level in the tube. The second method applied is a direct one. A novel flow sensor 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.
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