Reverberation Chamber


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reverberation chamber

[ri‚vər·bə′rā·shən ‚chām·bər]
(acoustics)
An enclosure with heavy surfaces which randomly reflect as great an amount of sound as possible; used in acoustic measurements. Also known as random diffusion chamber.

Reverberation Chamber

 

a room used for acoustic measurements, in which sound is reflected as completely as possible from enclosing surfaces, the average sound pressure is the same at every point, and the arrival of sound waves from different directions is equally probable.

The walls of a reverberation chamber are built of reinforced concrete and brick, while the interior surface is finished with materials that exhibit minimum sound absorption, such as high-grade cement mortar and marble. A diffusive sound field is achieved by making the reverberation chamber irregular in shape, with nonparallel enclosing surfaces and specially designed irregularities on the walls, and by suspending reflecting elements in the form of curved plates in a random fashion throughout the room. A reverberation chamber is usually insulated from external noise and vibrations. A sound field is produced within the room with two to four loudspeakers oriented toward the corners of the room.

A reverberation chamber with a volume of approximately 200 m3 can be used for measuring the sound absorption factor of various materials, calibrating microphone and noise meters, and measuring the volume of the loudspeakers and the acoustic output of machines and other sources of noise. Hearing tests and noise-level tests are also conducted in reverberation chambers.

Sometimes reverberation chambers are also used to measure the characteristics of electromagnetic waves; in this case, the inside of the room is finished with copper foil. Two adjacent reverberation chambers, each having a volume of approximately 50 m3 and a common aperture in one of the walls, are used to study the sound-isolation properties of various materials and structures in architectural and construction acoustics. The quality of a reverberation chamber is characterized by its reverberation time and the uniformity of its sound field.

REFERENCES

Beranek, L. Akusticheskie izmereniia. Moscow, 1952. (Translated from English.)
Blinova, L. P., A. E. Kolesnikov, and L. B. Langans. Akusticheskie izmereniia. Moscow, 1971.

reverberation chamber

A room, having a long reverberation time, which is especially designed for the measurement of the sound absorption coefficients of an acoustical material or the sound power of a sound source.
References in periodicals archive ?
Figure 4 shows the smooth reflecting inner surfaces of the reverberation chamber along with the horizontal stirrer.
Measurements and evaluations of multi-element antennas based on limited channel samples in a reverberation chamber," Progress In Electromagnetics Research, Vol.
Pomianek, "On simulating the radio signal propagation in the reverberation chamber with the ray launching method," Progress In Electromagnetics Research B, Vol.
Capsalis, "FDTD calculation of quality factor of vibrating intrinsic reverberation chamber," Electronics Letters, Vol.
The DSTO's mode-stirred reverberation chamber provides uniform, isotropic (i.
A reverberation chamber has been exploited to obtain incoherent sources [45] since, as known, the coherency length of the reverberating field is of the order of [lambda]/2 [46].
When we measure the three-element IULA array in the reverberation chamber with three fixed wall antennas (as in our case), we can define 3 x 3 = 9 channels, and find the combined capacity of the 9 channels from the channel matrix [H.
Goodness-of-fit (GOF) tests [14] were popularly used in studying the distribution of the random field in a reverberation chamber (RC) [5,6].
Measurements were performed in the reverberation chamber located at Wroclaw University of Technology.
Room qualification measurements were performed in the reverberation chamber following AMCA Standard 300 (1996) with a Larson Davis 2900B sound analyzer and an Acculab model R.
You don't want to build a sound-proof box," says VanBuskirk, "because any sound that does leak through turns the interior into a reverberation chamber.
The reverberation chamber provides a dynamic free-space reference environment upon which wireless channel emulators apply real-world spatial channel models.