Comparison of acoustic 3D spacer fabrics with traditional acoustic materials: Limitations and potentialities

Acoustic textiles are the most widely used acoustic materials to control room acoustic parameters in current practice. Based on porous acoustic absorption, they are able to achieve high absorption at middle and high frequencies. This behaviour is a limitation for spaces that host speech comprehension or activities that require concentration. For this reason, acoustic sector companies tend to explore the advancements in other sectors (e.g. technical apparel, transportation, etc.) to find solutions that can satisfy this requirement. This is the case of 3D spacer fabrics (3D SFs) which, thanks to the two horizontal layers and the internal connecting vertical pile, have complex and customisable structures adaptable according to the acoustic performance (absorption, reflection, diffraction). Originally developed to provide sound insulation in transportation vehicles, these materials’ acoustic performance has been explored, but a comprehensive and updated research review is lacking. In response, this paper presents a systematic review aiming to understand the correlation between the physical characteristics of these materials and their acoustic performance. The review is based on the literature of the last 10 years of reviewed and published papers. Absorption coefficients are gathered, sorted and compared with the most extensively used acoustic materials. This contribution shows that the main performance analysed is absorption and this depends on thickness, porosity, and flow resistivity of the horizontal layers. The complex pile structure of 3D SF enables absorption coefficients that are comparable with the most common acoustic materials. The analysed references are based on literature absorption coefficients measured in an impedance tube. Future research should explore the possibilities of 3D SF application at an architectural scale by analysing the absorption coefficients in a reverberant chamber or by analysing reflection and diffraction behaviours.