There are many applications where glass is used extensively, such as atria, lobbies, offices, museums, board rooms, etc. Excessive reverberation and interfering reflections are often the result. However, traditional sound absorptive materials applied over these surfaces would defeat the initial intent to provide outdoor views and natural lighting. Now a new acoustical technology is available to address these acoustical needs, while maintaining the transparent design intent. Clearsorber™ Foil is based on new patented technology, utilizing microperforations in a transparent or translucent sheet. When the foil is spaced off vision glass, these microperforations produce significant viscous losses, providing the necessary sound absorption. Applications are only limited by the imagination. The Future Is Clear!

Clearsorber Foil is a thin, microperforated, polycarbonate foil (Kaetaphontm) 0.105 mm thick, with a surface weight of 0.14 kg/m2. The hole diameter is 0.21 mm and the holes are spaced 2 mm x 2mm apart. The maximum width of a roll is 1 m (3.28’)

Problem
Projects designed with extensive use of glass surfaces can produce strong interfering reflections and excessive reverberation, which create an uncomfortably loud ambiance causing fatigue and corrupting speech intelligibility.

Solution
To address these acoustical problems, while maintaining natural lighting and views to the outside, RPG introduces Clearsorber™ Foil, made from microperforated polycarbonate. If the perforations in a Helmholtz resonator are made sub-millimeter in diameter, they are comparable to the thickness of a boundary layer of air. As sound passes through these microperforations, sound absorption will occur due to viscous boundary layer effects in the perforations, as long as an air cavity is provided between the foil and the vision glass. It is then possible to achieve sound absorption without the need for additional porous material in the cavity behind the microperforated sheet, thus allowing the panel to be transparent or translucent. Therefore, the Clearsorber™ Foil offers an acoustical solution when a clear absorber is required.

Absorption:
Sound absorption is provided by viscous losses in the microperforations, whose sub-millimeter diameter is comparable to the thickness of a boundary layer of air. As sound passes through these microperforations, sound absorption will occur due to viscous boundary layer effects in the perforations, as long as an air cavity is provided between the foil and the vision glass boundary. It is therefore possible to achieve sound absorption without the need for additional porous material in the cavity behind the microperforated sheet, thus allowing the panel to be transparent or translucent. In addition to a single foil layer, multiple, separated, foil layers can be used to broaden the range of frequencies over which efficient absorption occurs.

Installation
Clearsorber™ Foil can be mounted single or double layer, with double layer providing broader bandwidth sound absorption. The foils are held in tension with springs stretched between a metal eye bolt and grommet in the corner of the foil.

Panels can also be tiled, using a 4-way attachment. An remotely controlled motorized roller shade is also available.

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Transparent Microperforated Foils From The Acoustical Industry’s Leading Innovator

Clearsorber™ Foil product information PDF (378 Kb)