Reduce room resonance for better sound
March 28, 2007
Room acoustics plays very important role in home theaters or other sound reproduction systems. Sometimes, you will like the sound quality and effect at listening rooms of a store and when you buy and eventually play audio system at your room, it may sound worthless of the price. The listening rooms are generally well designed with the help of an acoustic engineer or architect and your room may not be.
In case of sound reproduction in room, if the room walls are exactly parallel, the more is the loss of quality. This is caused by a phenomenon called “Standing waves” or “room resonance”.
What is room resonance?
The sound waves emitted by the loudspeakers travels in all directions. The waves propagated to the sides will eventually hit the walls. The wall will absorb some part of sound energy and the remaining is refllected from the wall. The degree to which the sound gets absorbed by walls is determined by the “absorption quotient” of the wall material. The reflected sound waves follow geometry and travel in the reflected direction. Thus, the sound waves reflecting from different directions, keep on hitting the opposite side walls, until the sound energy is completely dissipated by absorption into the air particles. This phenomenon is the main cause for room resonance to occur, though it depends on the wavelength of the particular sound and the distance between the walls.
This can be even severe in closed rooms, wherein the sound reflections happens
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between each set of opposite walls,
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between ceiling and floor, and
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involving all six surfaces
How to reduce the standing waves or resonance?
There are mainly two types of solutions. One is an ultimate solution, which deala with the room architecture. The room can be designed with acoustics in mind, by making the walls non-parallel, but at the same time, no compromise for the room look. Several engineering structure are available to approach this.
The second solution, very effective and simple, is to use drapes in the room. Ofcourse, little bit of research is required to select suitable drapes. Check for their absorption quotient and buy suitable ones. Infact, by listening to various frequencies in your room, you can make out, what absorption quotient is helpful. You can also consult a acoustic consultant, who will meausure the distance between the walls and analyse the wave spectrum for your room and suggest a good material for drape.
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