RPG Modffusor

In 1983, RPG Diffusor Systems, Inc. introduced the first commercial sound diffusor that offered uniform scattering over a designable bandwidth. The QRD® has now been used in thousands of projects in a wide range of venues. As with any technology, research and experimentation lead to advances. The QRD® is a reflection phase grating formed from the periodic repetition of a base shape, consisting of a series of wells of depth based on the quadratic residue sequence, separated by dividers. While periodicity is the basis of the QRD®, it is also one of its limitations, because periodicity causes lobing in specific diffraction directions. To minimize this lobing, which compromises the uniformity of the polar response, RPG developed the Modffusor™. By contrast to a QRD® periodic array, a Modffusor™ aperiodic array is formed by following the prescription of an optimal binary sequence, which indicates when to use the asymmetric, optimized base shape or a flipped version (rotated 1800 about the surface normal). The shape optimized Modffusor offers significantly better performance than a low-prime, number theoretic QRD® diffusor and the aperiodic modulation minimizes lobing non-uniformity caused by periodicity. Thus, the Modffusor™ offers the next generation of high performance reflection phase gratings.