MEASURING DEVICE OF BENT CHARACTERISTICS OF BENTED EARPHONE

摘要

PURPOSE:To obtain the earphone characteristics equal to the human ears by means of an acoustic coupler of a simple structure by an operation processing to both acoustic impedance of human ears stored in a memory and sound pressure output of an earphone to be measured. CONSTITUTION:An earphone (not shown in the figure) to be measured is attached to an artificial ear 10 consisting of acoustic tubes 3 and 5 with a simple structure and stable characteristics, and the impulse response sound pressure of the earphone is measured by means of a microphone 2. The bend characteristics Hc (curve C) and the insertion gain Ginc of the earphone on the ear 10 are calculated from said response sound pressure with a prescribed operation. Then the bend characteristics Hr of a human ear (equation I ) and the insertion gain Ginr (equation II) are calculated from the acoustic impedance Zinr of the human ear stored in a memory and the impedance Zinc of the ear 10. Thus it is possible to obtain a result (curve A) which is almost equal to the actual characteristics (curve B) of the human ear without using an acoustic coupler such as a Zwislocki coupler, etc. having a complicated structure and unstable performance.