Destructive interferences created using additive manufacturing

Current solutions to absorb sound have technical limitations in being tailored to the specific acoustic requirements of a space. In fact, porous materials show high absorption at higher frequency, while at low frequency, the use of porous materials often require an impracticable significant thickness. Alternatively, resonance absorption mechanisms (either Helmholtz resonators or vibrating panels) show low frequency absorption but in limited frequency ranges. This research focuses on absorbers created using additive manufacture in order to absorb in the low frequency rage using passive destructive interference principles. Additive manufacturing allows for the fabrication of unique pieces with complex and freeform curved geometries. Focusing on geometrical aspects, this paper presents the results of the investigation of an ongoing project to create a large thin transparent panel with absorption above 0.6 below 250 Hz with limited thickness.