When designing a room, such as a concert hall, it is important that the reverberation time of the space is correct so that speech is intelligible and music sounds good. You are probably familiar with spaces such as railway stations which are too reverberant - they have too little absorption which makes it difficult to communicate. Knowing the absorption of architectural materials is vital when designing a room with good acoustics. The reverberation room is used to measure absorption coefficients of materials used in buildings throughout the world.
Acoustic diffusers are used to treat room acoustic defects, but there has long been concerns about the amount of sound absorption that Schroeder diffusers provide. Measurements in this room were used to quantify and ultimately explain the cause of the absorption, and hence enable diffusers with low absorption to be made.
Researchers at Salford developed a standard test method for auditorium seating which is now used to test the seating of major concert venues such as the Royal Albert Hall. Read a case study of how the reverberation chamber is used to test theatre seating.
UKAS accredited tests & standards
Measurement of absorption coefficients to BS EN ISO 354
Measurement of road traffic noise reducing devices to BS EN 1793-1, 2 & 3
Impact improvement testing to BS EN ISO 140-8 using our heavyweight testing floor
This room is designed to be very reverberant, so the walls are made of painted dense brick. It has a reinforced concrete sloping roof and a non-parallel pair of walls to make the room more diffuse. The reinforced concrete floor is built on a rockwool insulation board to provide vibration isolation.
Reverberation rooms like these are used to test the absorption of materials used in rooms and in noise control. This small reverberation room is used mostly for final year and postgraduate research projects.
This room was used as a simulated kitchen to record washing machine sounds as part of a Department of Trade and Industry project looking at methods to test the sound quality of products. Absorbent was added to the room to make it less reverberant and more like a kitchen.
Absorbing low frequency sound is difficult, because treatments have to be very large to work efficiently. Active control offers the possibility of bass absorption from relatively shallow surfaces, as well as the possibility of variable acoustics. This room has been used to pioneer techniques for active absorption, where loudspeakers are used to generate sounds to reduce the effects of room modes.