Concert halls and recording studios are covered with thick veneer with large cavities that effectively muffle external noise. As sound waves travel through the air, acoustic materials significantly hinder its circulation. Researchers from Boston University solved this problem by creating a rather simple device that muffles up to 94% of external noise, retaining the ability to pass air. Its effectiveness has been proven in the course of the experiment, captured on video.
The new “silencer” is a printed on a 3D printer ring form which is made according to precise mathematical standards. The material in the outer ring is twisted as a spiral, this structure prevents the sound to pass through the open center, pushing the sound waves back toward the source.
To test the effectiveness of the device, they put the ring on the PVC pipe, one end of which resting against the trend. When the speaker started making white noise on the other end of the pipe it is virtually never heard. When the silencer was removed, the sound seemingly filled the whole room. According to researchers, the device could drown 94% of the noise.
We observed this kind of results in computer simulation for several months, but it is one thing to see the results on the computer, and another to hear them in reality.
Jacob mikalaichyk, 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 outlet openings of jet engines, and even in ventilation systems of 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 hexagon. Our design is very light, open and beautiful. Every detail can be used as tiles or brick to create a sound permeable wall.
Reza Affirimative, one of the authors of the study
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