skip to content
RPG Hemiffusor

Hemiffusor

RPG® Hemiffusor® 2D Quadratic Residue Diffuser

                        Hemiffusor

Conventional acoustic treatments have relied on absorption for reflection control. Unfortunately, this can “deaden” the room and make it unsuitable for speech or music. Diffusive ceilings are one of the most effective ways to simultaneously control room reflections and provide a natural ambience. The Hemiffusor™ uniformly scatters sound arriving from any direction into many directions, providing ideal distribution and coverage. Its unique shape creates an attractive, visually interesting acoustical surface.

Specular reflections from flat, hard surfaces cause strong reflections that corrupt speech intelligibility and degrade music quality. Typically, fabric wrapped absorptive panels are used to control interfering reflections, with the undesirable side effect of deadening the space.

Solution

The Hemiffusor™ is the first and most affordable 2D QRD®. It offers twice the reflection attenuation of the 1D QRD®, because it uniformly scatters sound into a hemisphere. The Hemiffusor™ provides uniform, omnidirectional, broad bandwidth diffusion in an attractive ceiling or wall design element.

Diffusion

The Hemiffusor™ offers significant diffusion compared to a flat reflector panel above the diffraction limit of 565 Hz,which is determined by the dimensions of the panel.Above this frequency,the graph indicates how the reference reflector becomes more and more specular as the frequency increases,whereas the Hemiffusor™ provides a constant diffusivity.

Sound strikes a two dimensional diffusing surface and is uniformly scattered into a hemisphere.

hemiffusor diffusion chart

Absorption

While the primary function of the Hemiffusor™ is to provide broad bandwidth diffusion, it also offers a modest and beneficial amount of absorption across the frequency spectrum with emphasis at 315 Hz and 800 Hz.

hemiffusor absorption coeff chart

Installation

The Hemiffusor™ is very easy to install on walls or ceilings using the supplied hook and loop fasteners. Apply both sides of the hook and loop fastener to the rear of the Hemiffusor™ in each corner on a flat area. Remove the protective paper from the exposed side and apply to the wall. For permanent mounting, construction adhesive must also be applied, where space allows on the back of the unit, along with the hook and loop fasteners. The Hemiffusor™can also be inserted into a T-bar ceiling grid.

Hemiffusor_pdf