Investigation of coprime sound diffusers using one-fifth scale modeling

Abstract

In acoustics, a room is often characterized by factors such as its ability to absorb, reflect, and spread the sound in it. The spreading of sound is generally accomplished with diffusers, which scatter sound based on the angle of incidence and frequency. These diffusers come in all shapes and sizes, which can be wall and floor mounted as well as encompass a volume of the room. Recent work in other fields has allowed for investigations on how this work could be implemented to diffuser theory. In one field of acoustics, sparse sensing for microphone arrays has led to the creation of the coprime linear array. The coprime array concepts can be applied to volumetric diffusers using cylinders. These are arranged in pairs of co-prime arrays in which the number of cylinders consist of two mutually prime numbers of elements for a sparse arrangement. Coprime sound diffusers are tested experimentally using one-fifth scale measurements as well as an acoustic goniometer to see how beneficial this diffuser could be in real world applications.