Sound absorption characteristics of slat curtain absorbers for adjustable acoustics

In connection with the refurbishment of a local church, the possibility of introducing adjustable acoustics via slat curtains was considered. Information of absorption characteristics of slat curtains in different configurations is very sparse, so prototypes of porous slat curtains were measured in a reverberation room according to DS/EN ISO 354.<br/>The slats were constructed from a porous non-woven absorption material with a thickness of 2.5 mm and a width of 16 cm. They were mounted in a standard slat curtain rail allowing for varying angles and retraction of the slats. <br/>A curtain section of 3 x 4 meters was mounted on a wall. The angle of the slats could be varied in steps from 0 degrees (fully closed and comparable to a stretched-out curtain) to 90 degrees (fully open and corresponding to a series of thin vertical acoustic baffles). Furthermore, the curtain can be retracted. In the case of a full retraction, the slats are forming a coherent volume of absorption material with virtually no gaps between the individual slats. When retracted partly, a number of the slats are in open configuration, and the retracted part forms a coherent volume. <br/>Results are presented as absorption coefficients and/or equivalent absorption areas for a variety of configurations varying the distance to the wall, the angle of the slats and the amount of retraction.<br/>