Abstract: The invention relates to a sound absorber (1) for a traffic route noise protection wall, wherein the sound absorber (1) comprises at least one plastic foam board (2). According to the invention, a first surface (3) of the plastic foam board (2) has a predeterminable number of sound absorber recesses (4) for predetermination of the absorption behavior with a predeterminable frequency response, wherein each of the sound absorber recesses (4) extends only through part of the thickness (5) of the plastic foam board (2).

Abstract: A panel with one or more perforations, having a front surface, wherein the contrast Cm between the front surface and the one or more perforations is less than 0.3, a sound absorbing system including a panel and a masking layer, wherein the masking layer is air permeable, and the use of the panel or the sound absorbing system.

Abstract: A perforated panel having a grid of perforations or holes formed at least partially therethrough for disposing hangers for holding objects thereon and having at least a black color pattern disposed on a surface thereof for camouflaging the perforations and for reducing the appearance of damage and/or stains occurring through use is provided. It is desired to have a base finish formed on the panel and a first color pattern and the black color pattern formed by spattering of paint on the panel, screen printing, or attaching a lamina having the first color pattern and the black color pattern thereon.