Acoustic Performance of Additively Manufactured Reeds as an Absorber

Environmental noise emission from a variety of sources affects the surrounding community by causing discomfort, and potentially disturbing sleep cycles. Current acoustic absorbers are able to effectively absorb sound over a large range of frequencies. However, these materials are not all suitable to being placed in more demanding environments such as aircraft engines or near highways. It was desired to find more robust materials for use in these situations that can absorb sound effectively in the range of 100-1500 Hz. Some recent research has shown that reeds, a natural biomaterial, have significant acoustic absorption below 1000 Hz. This phenomenon is not well understood and has led to a new interest in developing test campaigns and models. This paper explores the effect of diameter, orientation, and spacing on acoustic absorption to optimize low frequency absorption. Several fixed synthetic reed test samples were designed, additively manufactured and tested for acoustic absorption in a normal incidence impedance tube. Natural reeds were also tested to compare to the results of the 3D printed synthetic reeds. Preliminary results show good acoustic absorption using synthetic reeds over the frequency range of interest.