Acoustic Diffusers | Sound Diffusors | Diffusion Panels | Sound Scattering Panels
RPG B.A.D Panel Diffuser
To accomplish diffsorption, RPG developed a new planar 2 dimensional
amplitude grating consisting of a 31 x 33 element array of 1,023 0.5 sq. in.
absorptive or reflective
The distribution of these resorptive binary elements is based on a 2 dimensional optimal binary sequence with a flat power spectrum. The resulting variable impedance surface forms a binary reflection amplitude grating suggested by James Angus. This is in contrast to reflection phase gratings which use phase variation, rather than amplitude variation, to provide diffusion. The Binary Amplitude Diffsorbor (BAD) Panel provides diffusion about an octave above the frequency whose wavelength is twice the size of the binary element. This explains the limitation of traditional variable impedance arrays. For example, 1' x 1' panels provide diffusion up to about 1 kHz. Remaining high frequency reflections would still corrupt speech and music quality.
Problem and Solution
Traditional fabric wrapped panels offer a cost effective, low profile aesthetic approach to providing reflection and reverberation control. However, these panels offer little sound diffusion and large area application may lead to an acoustically dead space. Variable impedance arrays offer some help, but cannot provide diffusion at mid and high frequencies.
The B.A.D. panel is an innovative variable impedance fabric wrapped acoustic panel with a binary template consisting of reflective areas and holes over a semi rigid fiberglass panel. The resulting Binary Amplitude Diffsorbor Panel provides mid and high frequency diffusion and low frequency absorption.
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The graphs above illustrate how the BAD Panels can offer an increase in bass absorption over a standard upholstered 1" panel below 1000 Hz, and a decreased absorption above this frequency. The binary template allows the sound above 1000 Hz to be uniformly diffused providing reflection control without destroying the rooms ambiance.
The performance of a scattering surface is characterized by the diffusion coefficient, which is the standard deviation of the 1/3 octave angular response, shown above at 12.5 kHz. The graph illustrates how uniformly the BAD Panel scatters sound across the frequency spectrum, compared to a reflective panel, for normal incidence.
Angular scattering response
For normally incident sound, the graph illustrates the angular response at 12.5 kHz. The flat reflector scatters sound primarily into the 90° specular direction. The wall mounted absorptive panel has similar response, only attenuated. The BAD Panel decreases specular scattering and more closely approaches the uniform ideal diffusion line.
BAD Panel diffusers are now also available with a curved front panel for improved diffusion. Contact Custom Audio Designs
for further information and costs.
All information contained in these details is given in good faith but without warranty.