58 Nonotuck Street    Northampton, MA 01062    (413) 584-7944    Fax: (413) 584-2377   Email: info@silentsource.com
credit cards
diffusors-bar.gif (1143 bytes)
0.gif (77 bytes)
RPG Diffusor Systems:   Diffusor QRD® PA
0.gif (77 bytes)

The QRD® Diffusor has long been the industry standard for recording studios. The new QRD PA is a lower-cost version of the classic.

This one-dimensional diffusor is a modular, reflection phase grating, which produces a directional hemi-disc polar response that can be oriented in any direction. It also provides low-frequency absorption, below the design bandwidth, due to the RPG® pressure-gradient mechanism.

Its wide bandwidth and low cost make it a logical choice for any project studio or home theater.

Interfering reflections that degrade speech intelligibility, gain before feedback, and music quality can be controlled by absorption and diffusion. Since commercial surfaces that provided uniform diffusion over a wide frequency range and for all angles of incidence were not available, absorption was used solely to control reflections. This treatment created “dead” spaces.

In 1983, RPG® introduced the first commercial QRD® Diffusor, based on mathematical number theory. Now the QRD® PA offers a lower cost alternative for the Pro Audio and Project Studio environment.

Compared to a flat reflector panel, the QRD® 734 offers significant diffusion above the diffraction limit of 565Hz, which is equal to the speed of sound (1130ft/sec) divided by the 2' dimension of the panel. As the frequency increases above 565Hz, the graph indicates how the reference reflector becomes more and more specular, whereas the QRD® PA provides a uniform diffusivity.

The QRD® PA is mounted on a supplied cleat and secured. For installations that require a flush mount the units are framed out much like an opening for a window.

0.gif (77 bytes)


  • QRD® sound diffusion
  • Distinctive textured appearance
  • Can be surface or flush mounted
  • Can be oriented to provide two dimensional diffusion in the far field
0.gif (77 bytes)
Material Description
Size (in)
Order Code
Ship Wt (lbs)
Black Melamine
23- 5/8 x 23 - 5/8 x 5
Faux Maple
23- 5/8 x 23 - 5/8 x 5
0.gif (77 bytes)

Acoustical Foams | Baffles | Barriers
Bass Traps | Ceilings | Diffusors | Fabric Wall Coverings | Fabric-Wrapped Panels
Gobos | Isolation Enclosures | Specialty Products | Contact Us

© 2016, Silent Source. All rights reserved.