Basic principles for setting and selecting sound-absorbing materials

A reasonable room reverberation time needs to define the sound absorption characteristics of each boundary surface. That is, different sound-absorbing material properties are set for each surface of the room to meet the requirements of the room's reverberation time characteristics.

1) The selection and setting of sound-absorbing materials on the inner surface of the room should be subject to the need to achieve the predetermined reverberation time goal of the hall. The final result requires that the operating frequency be as close as possible to the desired value of the reverberation time RT desired.

(2) Several sound-absorbing surfaces that play a key role in the reverberation time should be set. For halls with an average volume of 4m3/seat to 5.5m3/seat, the ceiling and back wall should be treated with sound-absorbing materials with a sound absorption coefficient of 0.4-0.6 to achieve a suitable reverberation time. For halls with an average volume of more than 5.5m3/seat, the ceiling and back wall should be treated with sound-absorbing materials with a sound-absorbing coefficient of 0.6 or more. Sometimes it is necessary to increase the sound-absorbing treatment on the side walls.

(3) Prioritize the surfaces that are most susceptible to sound waves, so that these surfaces can fully absorb sound waves to reduce the reverberation time. The most suitable surface for sound absorption treatment is the ceiling, followed by the side walls and the back wall of the auditorium. When arranging sound-absorbing materials, it is not advisable to use strong sound-absorbing materials on a few surfaces and leave the other surfaces untreated.

(4) When arranging sound-absorbing materials on the side walls, it should be considered in conjunction with lighting.

(5) The sound absorption treatment of the back wall of the stage should also be considered to reduce the acoustic feedback and increase the sound transmission gain.

(6) When selecting sound-absorbing materials, the balance of the sound-absorbing frequency characteristics of the materials must be considered in order to maintain a good listening experience for the listeners.

(7) The sound-absorbing material itself also has the following requirements: a high sound absorption coefficient in a wide frequency range; a small weight while maintaining a high sound absorption coefficient, good moisture resistance, no smell that harms human health; no corrosion of the sound absorption structure, not easy to burn; the construction is simple, the sound-absorbing performance is stable for a long time, the material is obtained on the spot, and the price is cheap.

(8) The selection of sound-absorbing materials should also take into account the decoration effect factors: a design that does not consider the decoration effect is not a good acoustic design. With the advancement of technology, a large number of new sound-absorbing materials are available. These materials have their own characteristics in texture, appearance and decoration effect, so that decoration designers can choose sound-absorbing materials according to their own understanding of decoration effects. This not only satisfies the acoustic design requirements, but also satisfies the decoration design requirements.