| 摘要 |
The present invention includes a printed circuit board, a diaphragm which is mounted on the printed circuit board and generates an electric signal by vibrating by a sound source, a case which packages the printed circuit board mounting the diaphragm and includes a sound pressure hole for transmitting the sound source to the diaphragm, and a sound filter which is mounted in the case, compensates the low band of the electric signal generated from the diaphragm and attenuates the high band of the electric signal. Case costs are remarkably reduced and sound properties are improved by simply forming the sound filter in the case without forming a preset space in the case according to the above configuration. |
