| 摘要 |
PROBLEM TO BE SOLVED: To improve clarity with only a casing structure and to improve reliability and productivity by converting a microphone into resistance, an air room into a capacitor, a sound hole into a coil and resistance into an electrically equivalent circuit. SOLUTION: A sound source 1 is substituted for a signal source S and the capacitor C of a volume V in the air room 5 of a volume V in front of the microphone 4. The sensitivity of the microphone 4 is substituted for the fixed resistor of a resistance value Rb, the sound hole 7 with a prescribed diameter is for the resistor of a resistance value Ra and the coil of inductance L. The capacity V of the air room 5 in front of the microphone 4 and the diameter are led by the electrically equivalent circuit. The volume V of the air room 5 where a necessary characteristic is obtained and the diameter of the sound hole 7 are decided in a stage where the casing 2 is designed. Namely, constants C, Ra and L led from the frequency characteristic for considering influence to the acoustic device by the structure of the casing 2 and improving the clarity of sound are inserted. The volume V of the air room 5 where the frequency characteristic for improving the clarity of sound is obtained and the diameter of the sound hole 7 are decided. |
