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RPG Modex Plate

Many rooms often suffer from low frequency modal problems and also require mid to high frequency reflection control.  Absorption at all of these frequencies has not been possible with a single acoustical surface treatment of 4" depth.

The Modex™ Plate solves these problems by offering significant absorption between 50 and 500hz in a surface depth of only 4".  The Modex™ Plate represents a new generation of acoustic bass management.  Now you can absorb more bass in less space!

RPG is proud to introduce a new and unique addition to the Modex™ line, called the Modex™ Plate.  Plate was developed by the Institute for Building Physics at the Fraunhofer Institute, and offers absorption effective from 50 - 5000hz in a thickness of only 4",  The Modex™ Plate has an attractive powder coated metal finish and can be surface mounted on walls or ceilings.

Surface or corner applied porous materials lose efficiency at low frequencies, because the particle velocity or air movement associated with long wavelengths is low.  The Modex™Broadband consists of a freely moving steel plate 1x1.5m sandwiched between porous layers.  Both react together in a mass-spring manner, offering absorption via three mechanisms.  First the plate provides pistonic absorption down to 50hz by vibrating against the spring of the porous backing.  Second, the bending modes of the free-moving plate are heavily damped by the proprietary adhesive coupling with the porous backing up to about 125hz.  Lastly, mid frequency sound waves diffract around the plate edges and through the perforated sides to be propagated, and thus, dissipated in the deep passive porous absorber layer.  Together, these mechanisms offer the industries first truly efficient, broad bandwidth low frequency absorber with a shallow profile of only 4 inches.
Low Frequency testing
Many published low frequency absorption coefficients are nonsense, because the accuracy of the absorption efficiency decreases at low frequencies in standard ISO 354 and ASTM 423 tests, due to inadequate diffusion.  Therefore, additional testing has been carried out at the Fraunhofer Institue in large scale impedance tubes with a cross section of 1.6m x 1.2m and a special approach monitoring decay times of the lowest axial modes in a 5x4x3 m room, with and without the sample present on one of the opposing surfaces.

The Modex™ Plate is installed by attaching metal 'L' brackets to the substrate.  The panel is then slid over and screwed to the brackets.  Panels should be installed at high pressure locations.  In order of highest to lowest efficiency, this would be the intersection of three boundary surfaces, two boundary surfaces and on one boundary surface.

Size - 1m x 1.5m x 100mm
Model Name: Plate
weight 70lbs
Finished in white powder coating
predrilled 'L' shaped metal mounting brackets supplied for easy installation


  • Three mechanisms of low frequency absorption
  • 50 - 5000hz absorption efficiency
  • High full spectrum absorption efficiency
  • Thin profile
  • Decorative perforated metal facing

The patented Modex™ Plate  damped metal system offers absorption via pistonic vibration, damped bending modes, and porous absorption from the rear and front polyester.
The three absorption mechanisms offer absorption over a significant range of frequencies providing modal control with one product.
absorption efficiency is high, thus requiring fewer panels for effective modal control
The thin 4" profile allows the Modex™ Plate to be used on exposed walls and behind T bar and stretch fabric systems. 
The perforated powder coated metal enclosure provides an attractive finish.

All critical listening rooms, including recording studios, vocal booths, home theaters, quality control rooms, CD mastering, film mix and dubbing stages,  music practice rooms and conference/teleconference rooms. 

The unit can be installed easily with the the brackets and self-tapping screws supplied. Modex Plate can also be powder-coated or fabric covered.

This product is heavy, and will require 2 persons to install.

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