Study on the Acoustic Characteristics of Ventilation Materials Applied in the Microspeaker

• Main Authors: WENG,JUI-CHU, 翁睿楚
• Other Authors: HUANG,CHEN-HUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/q9grp4

碩士 === 逢甲大學 === 電聲碩士學位學程 === 106 === Ventilation paper is not only one of the important components but also a complex mechanism in microspeaker. Based on the characteristics of acoustic resistance, the amplitude of f0 and SPL can be suppressed. Instead of a scientific methodology, the selection of ventilation paper is only by listening and try-and-error. It is time consumption. Thus, how to create a systematic and scientific method in selection is main topic of this thesis. This article is beginning from 10 different ventilation papers and used in two microspeakers which are 20 mm and 40 mm in diameter, respectively. The specific airflow resistance of ventilation paper is measured by self-made flow resistance system based on ISO 9053. In addition, the perforated panel theorem with capillary published by Dr. Ma is also adopted and discussed in this article. Finally, a completed system in the selection and simulation of ventilation paper is built-up. Results show that specific airflow resistance of ventilation paper is the most important parameter applied in the microspeaker. It not only brings the suppressions in the amplitude of f0, but also eases the changes in the suspension edge in the higher frequencies. For this article, the specific airflow resistance of ventilation paper between 119 ~459 Pa.s/m is suitable for both microspeakers. In addition, the perforated panel theorem with capillary published by Dr. Ma is only working below 25 Pa.s/m in specific airflow resistance. For others ventilation papers, they can be obtained only by flow resistance system. This methodology is not only suitable in the ECM simulation, but also proved to apply in the selections.