As far as metallic wall panels for the reverberation control of a room are concerned (also known as acoustic insulation panels) such as those used for current applications in the field of industrial soundproofing or in premises of tertiary buildings, like reducting the reverberation of a room or increasing the spatial sound decay in a room, they generally consist of an absorbent filling (quite often: mineral wool) covered by a surfacing (mostly: a fiber glass) and also by a perforated protection (mostly: galvanized or painted steel). A powder coating usually provides the best possible protection against corrosion: up to classification C5 according to ISO 12944 whereas providing a visual aspect appropriate for the context. As required, the perforations of the protection can be generally circular (perforated plate) or in the form of slots (absorbent panels with metal blades).
In some cases, the frame of metallic wall panels (metallic absorbing panels) can be made of stainless steel (SS 304, SS 316) or of aluminum.
As required, the absorbing lining may consist of acoustic foam or of polyester wool and for some applications, protected by a waterproof surfacing (polyurethane film and for extreme cases: painting).
In order to increase the absorption coefficient in a given frequency range, an intermediate plate (usually made of steel) and also a additional absorbent spacing layer may be inserted into the metallic wall panels, the performance of such absorbent panels then being (partially) based on the effect of resonant membrane (also known as resonator).
The prediction of acoustic performance of metallic wall panels can be performed with the simulation software SILDIS®®.
The verification of acoustic performance of metallic wall panels can be made in accordance with ISO 354 Acoustics - Measurement of sound absorption in a reverberation room