OPTISOUNDWOOD project: enhancing poplar plywood with sound absorption properties.

The paper presents the results of a project funded by the Piedmont Region – Northern Italy – aimed at developing, testing and manufacturing innovative wood-based products for acoustic improvement and mainly realized with poplar plywood. This species was chosen both for its remarkable lightness and because it is the only local wood, with long arboricultural tradition, for which the offer of timber can meet the industrial needs. After an introduction on the state of the art and trends of poplar cultivation in Italy, the paper describes the artifacts (sound absorbing perforated panels, frames and bass traps) developed within the project. The research envisaged a preliminary investigation through physical models that guided the realization of perforated small-scale specimens. Tests were carried out with the impedance tube method and the more interesting drilling patterns were realized on products in end-use dimensions. These were installed and tested in a dining hall and their sound absorption properties were also determined using the reverberation room method. Since developed products are also proposed as furniture elements their appearance represents a fundamental issue. For this reason different kinds of surface finishing were experimented: painting, milling of decorative figures, image printing and tissue coverings. Technical aspects related to assembly and installation of end products were also considered. The final products showed interesting sound absorption properties in the low frequency range and poplar plywood turned out adequate for satisfying the requirements foreseen by the proposed uses