On the Use of Perforated Sound Absorption Systems for Variable Acoustics Room Design

Abstract

An important challenge for acoustic engineers in room acoustics design is related to the acoustic performance of multi-purpose auditoriums, which are typically designed to suit several performance requirements. With this intent, the analysis of several scenarios is usually performed individually, and then an acceptable solution, that may be adapted to several situations, is selected. One way of providing a more appropriate acoustic performance for each function of the auditorium is using variable sound absorption techniques to control reverberation and other relevant acoustic phenomena associated to sound perception. In this paper, the acoustic behavior of a perforated system that may be suitable for achieving a variable acoustic solution for room acoustic design is addressed. In the design of a cost-effective solution, the surface appearance is kept unchanged, while variable acoustic behavior is achieved either by closing the holes in the back face of the perforated panel or by placing a porous material in varying positions inside the backing cavity, thus accomplishing different acoustic requirements within a multipurpose auditorium. An analytical approach, based on the transfer matrix method is employed for preliminary acoustic sound absorption assessment provided by the system and to develop optimized solutions. Diffuse sound absorption is then computed and used to simulate, by the ray-tracing method, the acoustic behavior of a multipurpose auditorium to demonstrate efficient acoustic performance for different types of use.

Tunable Perforated Panel Sound Absorbers for Variable Acoustics Room Design

“…While several numerical approaches have been recently proposed for the acoustic simulation of rooms with perforated panel absorbers, either using the finite element method (FEM) [21,22] or the finite-difference time-domain (FDTD) method [23,24], the ray tracing approach was herein chosen for the sake of simplicity and computational efficiency, as is usual in room acoustics design. The implementation carried out in this work followed a similar procedure to that used in a previous work by the authors [25], which proved to be successful in the simulation of a conceptual auditorium.…”

Sustainable Perforated Acoustic Wooden Panels Designed Using Third-Degree-of-Freedom Bezier Curves with Broadband Sound Absorption Coefficients

“…Variable acoustic features are a desirable property for common materials as they allow the modification of the acoustic conditions in a room [ 2 , 39 ]. In order to investigate the influence of variable configurations of overlays within a single panel on the sound absorption coefficient, several analyses were conducted.…”

“…Acoustic engineers frequently use acoustic perforated panels because of their flexibility in shaping their absorption characteristics with hole size and diameter modifications. However, irregular hole placement is not common [ 2 , 3 ]. The basic concepts of novel types of perforated panels will be explained with a comprehensive description of the following features: The scientific method used to reach the desired broadband sound absorption; The influence of the third-degree-of-freedom front face of the wooden panel; The possibilities of final panel property manipulation with the exchange of the front wooden overlays.…”

“…Acoustic perforated panels are widespread in public spaces because of their acoustic and construction performances. However, most currently used designs are based on a regular hole placement in the grid [ 2 ]. They are easy to design thanks to the well-known analytical equations for perforated panel construction [ 4 , 5 ].…”

“…Acoustic engineers frequently use acoustic perforated panels because of their flexibility in shaping their absorption characteristics with hole size and diameter modifications. However, irregular hole placement is not common [2,3]. The basic concepts of novel…”