Concert halls and recording studios are covered with thick cladding with large cavities that effectively drown out external noise. Since sound waves propagate through the air, acoustic materials noticeably impede its circulation. Researchers from Boston University solved this problem by creating a fairly simple device that muffles up to 94% of external noise, while maintaining the ability to pass air. Its effectiveness was proved in the course of the experiment, filmed on video.
External noise silencer
The new “silencer” is a ring printed on a 3D printer, the shape of which is made according to precise mathematical standards. The material in the outer ring wraps around like a spiral-this structure prevents sounds from passing through the open center, pushing the sound waves back towards the source.
To test the efficiency of the device, they put a ring on a PVC pipe, one end of which is leaning against the speaker. When the speaker began to make white noise, it was almost inaudible at the other end of the tube. When the silencer was removed, the sound seemed to fill the whole room. According to the researchers, the device was able to muffle 94% of the noise.
We’ve seen this kind of results on computer simulations for months, but it’s one thing to see the results on a computer and another to hear them in reality.
Jacob nicolaichik, one of the authors of the study
The authors of the project believe that such a device can be useful in a huge number of situations where it is important to muffle the sound without blocking the air. For example, such a filter can be placed around the exhaust openings of jet engines, and even in the ventilation systems of the premises. It is noteworthy that the device does not have to have a round shape.
We can give the device the shape of a cube or a hexagon. Our design is very light, open and beautiful. Each piece can be used as a tile or brick to create a sound-absorbing permeable wall.
Reza Affirimative, one of the authors of the study