Measuring noise level reduction using an artificial noise source

Residences near airports may be subjected to significant noise levels. The impact of aircraft traffic noise imposes a higher level of design consideration for the outdoor-to-indoor transmission of sound for residences. Noise Level Reduction (NLR) is a common metric used to quantify the ability for a building element to reduce the transmission of external sound pressure levels generated by aircraft. The aircraft noise mitigation measure is determined by the estimate of NLR and the building location in the airport’s noise footprint. While NLR may be measured using an actual traffic source (i.e., aircraft fly-overs), another practice is to perform measurements using a loudspeaker. An investigation is underway to better understand the loudspeaker methods of measuring NLR for buildings. Specifically, the study was tasked with quantifying various factors of these measurements such as angular dependency. NLR measurements were taken on the facade of a “test house” that was constructed for the purpose of the resea...