Determination of the sound energy level of a gunshot and its applications in room acoustics

• Published in: Applied acoustics 2016-04, Vol.105, p.99-109
• Main Authors: Deželak, Ferdinand, Čurović, Luka, Čudina, Mirko
• Format: Article
• Language: English
• Subjects: Measurement; New method; Room acoustics; Sound reduction index
• ISSN: 0003-682X; 1872-910X
• DOI: 10.1016/j.apacoust.2015.12.001

•Measurement of sound energy level of gunshot in free field over reflective surface.•Determination of apparent sound reduction index using gunshot as a noise source.•Determination of sound reduction index using conventional method for comparison.•Determination of apparent sound reduction index in widened frequency band. In some cases an impulsive noise source such as a gunshot can be a preferred alternative when investigating building acoustics, including sound insulation measurements, when compared to conventional steady state noise sources. A gun equipped with blank cartridges is an impulsive noise source that is lightweight and small enough to be easily transported. The differences in the noise characteristics between individual cartridges for the same gun are usually small, so the impulsive source can be replicated to a high degree. This paper is focused on the practical application of the sound exposure levels produced by a gunshot with a known sound energy level in the rooms under investigation. In this way, the equipment and methods required by the conventional method are simplified significantly. Furthermore, reverberation times need not be measured, since the equivalent absorption area can be directly obtained from the measured sound exposure levels. Using Green’s theorem, the roles of the sound source and measuring microphone were exchanged, which simplified the determination of sound insulation as it was easier to change the position of the gun than the microphone. The results obtained using the impulsive noise source were in good agreement with those obtained using the conventional method. Above 100Hz, their difference in any frequency band of interest was less than 1dB.