| 摘要 |
PURPOSE:To attenuate acoustic pressure at low frequency and to make easier to hear sound by providing the second acoustic leakage to leak sound produced by a piezo-electric vibrator, backward along an exhaust chamber board without passing the sound through the exhaust chamber. CONSTITUTION:A diaphragm 14 comprises a piezo-electric vibrator 15 which is bonded by a ceramic piezo-electric body 13 and a bonding agent. An exhaust chamber board 18 possesses the first acoustic leakage hole 20 which connects an exhaust chamber board 19 with atmosphere, and also possesses the second acoustic leakage hole 22 which connects an input terminal 21 and a front air chamber 17, and atmosphere. A vibrator 15 is furnished with a small hole 23 which makes a connection through the leakage hole. A case 16 holds a sound release hole 25. Thus separating the sound release 25 from the leakage hole 22 in the front air chamber 17 and selecting properly the hole 22 in size and numbers, then a sound level at low frequency is attenuated. |
