Window Stops Noise; But Lets Air Flow Through

Researchers have succeeded in developing a new type of window that brings your wild imagination to reality. The window blocks sound but lets the air flow through it; incredible, isn't it? Thanks to some of the latest, exotic acoustic techniques that make this possible. Allowing the air to pass through but blocking all the noise is an interesting challenge and an expensive one as well. Regular soundproofing methods involve transferring sound from the air into another medium which absorbs it and attenuates it.


The challenge got Sang-Hoon Kima at the Mokpo National Maritime University in South Korea and Seong-Hyun Lee and the Korea Institute Of Machinery and Materials exited. They have demonstrated a unique way of separating sound from the medium (air) and attenuating it, resulting into development of a new Window that can let the air to pass through it but cancels out noise.

The design process begins with a solid material with a negative bulk modulus. Kima and Lee designed a sound resonance chamber in which resonant forces resist any compression. The design is very simple. It comprises of two transparent, parallel acrylic plastic plates about 150 sq.mm separated by a small gap of about 40 mm. This design leads to a negative bulk modulus for a certain spectrum of frequencies. The team drilled 50 mm holes through each piece of the acrylic to diffract the sound that hits the chamber. These holes also allow the air to pass through them.

Kima and Lee have used their double-glazing unit to build larger windows. Their prototype 3x4x3 ft. wall of building blocks could reduce the sound level by 20-35 dB over a range of 700-2200 Hz.

The researchers believe that their idea can be used in protecting marine life from noise pollution and of course in the industries where the noise levels are high.

Read more about the research on the source link below:-

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