noise room

Noise room (noise room) is to simulate the free field space indoors, so the sound absorption coefficient of each surface in the room is required to be above 99%. It is impossible to design a sound absorber which can achieve 100% of the half frequency band (20 Hz-20Hz-20000Hz). Because common materials can easily absorb high-frequency sound waves, while low-frequency absorption is related to the thickness of the material (the length of the wedge). Cut-off frequency means that above this frequency, the sound absorption system of the wall can guarantee 99% sound absorption coefficient. In practice, the semi-free sound field space refers to the sound wave above the cut-off frequency. The lower the cut-off frequency, the greater the length requirement of the wedge. Generally speaking, the length of the wedge is suitable for the 1/4 wavelength theory.