Narrow Frequency Range Problem of Sound Reflector Arrays

Abstract

Overhead stage canopies composed of many panels suspended under ceiling provide proper acoustic eld in concert halls and auditoria. The purpose of using these structures is adequate direction and partial dispersion of sound reected from them. Frequency range of sound reected from at panels closely depends on their shape, size and conguration. It is often too narrow and therefore insucient for the proper sound of the interior. Mutual dependence of the lower and upper frequency limit of sound transmission requires the search for other ways to improve these structures. The paper proposes some solutions concerning spatial structures which have not been yet dened. An attempt was made to determine the useful frequency band of sound transmitted through such reective structures.

Analysis of the Accuracy of Uncertainty Noise Measurement

“…Finally, it should be added that not only sound noise measurements assume a normal probability distribution of results. This assumption, often incorrect, is commonly used in other acoustic measurements, e.g., of acous-tic structures' parameters (Kamisiński et al, 2012;Szeląg et al, 2013). Therefore, it is important to choose carefully the method for determining the acoustic measurements uncertainty due to the specific probability distribution of the results.…”

The Characteristic of Sound Reflections from Curved Reflective Panels

“…Properly designed reflective structures should provide the sound reflection in the wide frequency range from about 250 Hz to 4 kHz, flat character of obtained frequency characteristic (±3 dB) and spatially uniform reflected sound propagation (Skålevik, 2006). The most commonly used are flat panels, which due to their shape, size and the configuration of elements evoke the problem of narrow frequency range of reflected sound (Szeląg et al, 2013). One of the solution to this issue might be the usage of panels with convex edges or semicircular ones (Rathsam, Wang, 2010).…”