Earphone characteristic measuring device.

摘要

An earphone characteristic measuring device comprises an acoustic coupler (3, 5) having an acoustic tube (3) simulated to an external auditory canal in which an earphone under measurement is to be inserted and an acoustic tube (5) of a smaller diameter having an acoustic impedance of approximately 320 ohms connected to an end of the first acoustic tube (3), a sound source (109) for emitting an impulse sound to the acoustic coupler, a microphone (2) mounted at the end of the first acoustic tube for picking up sound pressure information and a characteristic calculation circuit (108, 110) for transforming an earphone characteristic of the acoustic coupler to an earphone characteristic of a real ear based on an input impedance of the acoustic coupler looked from an end of a pinna of the earphone inserted in the acoustic coupler and an input impedance of the real ear corresponding to a sum of an eardrum impedance of the real ear and an external auditory canal volume, stored in a memory (104, 106) in response to the sound pressure information from the microphone. The use of the acoustic coupler of a simple structure facilitates the measurement of a vent characteristic of the earphone and an insertion gain and improves reliability of the measurement.