The QRD® 734 has proven to be the most popular and versatile diffuser in the RPG® product line. It’s wide bandwidth, low cost, and broad selection of finishes make it a logical choice for music education facilities, recording studios, worship spaces, auditoriums, theaters, and performing arts facilites.

This one dimensional diffuser is a modular, computer designed phase grating which produces a directional hemidisc 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.

Problem
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.

Solution
In 1983, RPG® introduced the first commercial QRD® diffuser, based on mathematical number theory. Now a predictable diffusive surface treatment is readily available.

Acoustical Performance
The onset of diffusion for the QRD® 734 occurs at roughly 320 Hz, as can be seen in the diffusion (blue) coefficient, which is a measure of how uniformly the surface scatters sound. The scattering coefficient (green), on the other hand, indicates how much of the incident sound is scattered into non-specular directions. The scattering coefficient is not a proof-of-performance metric, but can be used in computer modeling programs to model scattering.

Installation
The QRD® 734 can be individually mounted or grouped into an array on a wall or ceiling.

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QRD® 734:

The First General Purpose QRD® Sound Diffuser From The Acoustical Industry’s Leading Innovator

QRD 734® Product Information (ZIP - 1,049 Kb) Downloading this file requires Winzip. 2 Page Brochure

Specifications CSI Specification Acoustical Data Order Code Wood Fact Sheet Fire Data Sheet Material Safety Data Sheet Warranty

Mounting Details All Mountings 2' x 2' Cleats 2' x 2' EE-EH Array 2' x 2' EJ-JH Array 2' x 2' Joining Wells 4' x 2' Cleats 4' x 2' EE-EH Array 4' x 2' EJ-JH Array 4' x 2' Joining Wells

Cutsheets All Cutsheets 2' x 2' EE 2' x 2' EH 2' x 2' EJ 2' x 2' HH 2' x 2' HJ 2' x 2' JJ 4' x 2' EE 4' x 2' EH 4' x 2' EJ 4' x 2' HH 4' x 2' HJ 4' x 2' JJ

Features & Benefits Features QRD® sound diffusion Custom Finishes are available Distinctive textured appearance Can be surface or flush mounted Can be oriented to provide two dimensional diffusion in the far field Available in transparent plexiglass: Benefits Attractive finish allows its use in a variety of decors Can be used to control unwanted reflections without adding additional absorption