Noise Level Reduction of .50 Caliber Gunfire by Terrain Shielding
Abstract
Gunfire at Army rifle ranges is an unavoidable part of military training that can disturb the surrounding community and become a source of complaint. Barriers can effectively screen noise in some scenarios, and are useful in reducing noise from small arms fire because acoustic energy from this noise source is concentrated at relatively high frequencies, making barriers of modest size large in terms of wavelength and capable of providing significant noise shielding. Larger guns exhibit more acoustic energy at lower frequencies, and therefore require much larger barriers to achieve effective noise reduction. This study investigated the reduction of .50 caliber machine gun noise by using terrain features as noise barriers. Measurements and calculations showed that berms and ridges can yield significant reduction of .50 caliber machine gun noise. A 3 m high beam yielded about 5 to 10 dB reduction in A-weighted sound exposure levels (ASEL) directly to the rear, while a roughly 10 m high berm yielded from 10 to over 20 dB reduction. The study concludes that propagation conditions and excess ground attenuation can also significantly affect achieved barrier insertion loss, and suggests noise mitigation strategies. Noise barriers, Noise reduction, Terrain shielding.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1994
- Accession Number
- ADA284439
Entities
People
- Larry L. Pater
- Raman Yousefi
- Walter Alvendia
Organizations
- Construction Engineering Research Laboratory