Development of small and robust implementation for acoustic impedance in situ measurement

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06689
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Architectural environment/Equipment
• Research Institution: Nihon University Junior College
• Principal Investigator: HOSHI Kazuma 日本大学短期大学部, その他部局等, 准教授 (50373171)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: カーディオイドマイクロホン / 吸音率 / 現場測定 / 音響管 / 音圧 / 粒子速度

Outline of Final Research Achievements

The purpose of this study is to explore the potential of new proposed sensor which has a pair of cardioid microphones for in situ acoustic impedance measurement. At first, the comparison experiments with existing sensors (Pressure-Velocity sensor and Two-Pressures sensor) and proposed sensor were conducted. As a result, it was clarified that the proposed sensor can be measured several acoustic materials in the 200 Hz to 4 kHz range. Secondly, in order to reveal the mechanism of impedance measurement using proposed sensor, normal incidence impedance was measured in an acoustic impedance tube with the proposed sensor. The results showed us that the proper detective ratio of sound pressure and particle velocity in a cardioid microphone affect the measurement. Additionally, it was confirmed when the ratio was corrected evenly, we could measure it as if the technique based on ISO10534-2.

Free Research Field

建築音響

Academic Significance and Societal Importance of the Research Achievements

技術の進歩に伴い，大空間かつ，高気密・高断熱な空間が増えてきた。これに伴い，音エネルギが空間に留まってしまい「響き過ぎて何を言っているか分からない」「音が大きくうるさい」といった空間も増加してしまった。内装材の吸音不足が原因である。しかし現在，現場の内装材の吸音率を測る手法は確立されていない。本研究は，あらゆる現場に対応できる扱いが容易なセンサーを開発することである。本研究で，既存のセンサーと同じように基本的な測定ができることを確認した。また，その測定メカニズムの大枠がわかった。このセンサーが実用化されれば，より容易に音のエネルギの流れを把握できることに相当するため，応用範囲は広い。