Window noise collection

The sound of the aircraft flying away, the traffic or the noise of the dance floor often caused residents of the area to get angry. But now, the first windows with an effective sound isolation system will bring lightness and comfort to residents while in their homes and offices.

When an airplane takes off on your roof every five minutes, you can't talk to anyone with that sound. A normal window cannot resist this kind of sound pollution.

A two- or three-layer thick glass will absorb high frequencies but it is impossible to resist low-frequency sounds like the sounds made by aircraft or the annoying bass of disco music. Thus, the glass panels should be so thick and heavy that it is almost impossible to use them in light construction structures or for the main faces of the building built with large curtain walls (light wall systems are hung in the end The frame is like the curtain, used for the facades using glass in buildings using frame structure).

Students are measuring vibrations in the structure of the noise-collecting window.The walls are covered with soundproof materials to prevent noise from being transmitted.(Photo: SzM Technische Universität Darmstadt).

'Tests have shown that our windows are capable of lowering noise to an average of 6 decibels with frequencies between 50 and 1000 hert. The sound collected inside the house is only half noise , 'said Dr. Thilo Bein, chairman of the Institute's Department of Energy, Environment and Health. 'We can even reduce the volume of some specific test signals up to 15 decibels'. Experts have predicted that the engine noise level of a passenger plane is reduced to 10 dB with a frequency range below 1000 Hz.

When noise waves meet the walls of the building, they can be transmitted inside by different lines. One is by making the window vibrate, so bring the noise into the building. Another way is to transmit sound waves inside through bridges in the frame structure, where the curtain wall elements adhere to the structure of the building. In both cases, scientists have found a way to prevent the transmission of sound energy.

Accelerating sensors are attached to the window panes to measure noise-induced vibrations. A thin chip made of piezoelectric material is also attached to the window to counteract vibration by creating vibrations of the same intensity but in the opposite direction to the vibration measured by the sensor - making the plate vibrates in the direction of opposition.

Scientists will present a prototype of this new soundproof window at the Hannover Fair from April 16-20 . According to Dr. Bein's estimate, this new effective noise-reduction window will probably be available in the market within the next 4 years.

Thanh Van