Why Absorptive Noise Barriers Are More Effective Than Reflective

Noise and sound created by roadways, railways, and other industrial noise sources are becoming one of the most contentious environmental problems globally. While noise pollution drapes over communities and US residents demand higher quality ways to lessen noise from the sound that’s created by their equipment. Outdoor sound barriers effectively provide an effective solution for these unfavorable noises that create unnecessary frustration and interference.

A noise barrier is a development beside roads that silence the rhythm of noises. Typically, two different forms of noise barriers are used. Reflective noise barriers, that are solid, break up then mirror sound back to the location it originated. Absorptive sound barriers are treated with sponge like materials that are normally located on the under layer of the barrier that break up and soak in noise. Absorptive noise barriers are mirrored into nature. Absorptive noise barriers have multi-sided enclosures immersing the noise reflections and maximizes the efficiency of the structures. With this valuable structure, the sound levels surrounding the location are lowered and weakened. Often times, you see less effective multi-sided structures built surrounding pumps and treatment equipment that are known as reflective sounds walls. They reduce the enclosure’s acoustical performance; however, they result in sub-par quality and louder outdoor sound levels that consume nearby and surrounding areas.

Concrete and reflective sound walls are well known for mirroring then returning noise back to the direction of the area that it came from and typically adding unforeseeable problems. One example happened back in 2011, when Mn/Dot constructed a sound barrier along highway I-94 in attempt to decrease sounds produced by highway construction and other pestering highway noises to bordering neighborhoods, consequently, Prospect Park residents complained that it actually did the exact opposite. Residents complained that because the wall was constructed unnecessarily high, which was the cause of the noise to ricochet over the highway, that amplified the noises rather than silencing the stressful noises. The problem seen that occurred here is called “reflection”. This is a rare occurrence where the noise reflects off of a wall of one side of the highway and deploys the noise in the direction of the other side. This is one reason that reflective sound walls are not as effective as absorptive sound walls. Reflective walls are made of wood, metal, and masonry having hard surfaces reflecting sound, however, the bulk of sound is reflected back in the general direction of the source of this noise.

When sound absorptive materials thought-out positioning and sizing are used in a noise barrier the sounds are partially or completely eliminated.
While reflection products made of materials like concrete have been the conventional material for sound barrier walls and HVAC enclosures, the highly developed absorptive sound minimizing materials present a greater efficient abatement option. Materials such as concrete or brick that are reflective they bounce sound waves off their surface in different directions that are sometimes unfavorable. For various outdoor noise issues, well-designed and effective absorptive sound walls are quickly becoming the noise alleviation solution of choice.