This presentation will describe a design for a new 286 m3 testing chamber that will allow the measurement of the random incidence absorption coefficient, according to ISO 354, the scattering coefficient, according to ISO 17497-1, the diffusion coefficient, according to ISO 17497-2 and the normal incidence low frequency absorption coefficient, according to ISO 10534-2. Optional dimensional ratios were determined by minimizing the standard deviation of the modal response. Both dome-shaped boundary diffusors and hanging panels are used to provide satisfactory diffusivity, which is verified using a 200 mm reference absorber according to ISO 354. The isotropy of the incident sound is measured with a new Sound Field Analysis Recorder (SOFAR) and quantified by an analysis of the wavenumber spectrum. A sufficiently large reflection free volume is provided in the chamber for boundary method diffusion coefficient scale model goniometer measurements. A new FDTD simulation program will be described to determine the diffusion and scattering coefficients of any 3D surface in the near and far field. A steel and concrete lined low frequency impedance tube measuring 600 mm x 600 mm x 5.8 m long and 7 tons will be used to measure absorption from 25-250 Hz.
|Title of host publication||Proceedings of 23rd International Congress on Acoustics|
|Number of pages||8|
|Publisher||Deutsche Gesellschaft für Akustik|
|Publication status||Published - 2019|
|Event||23rd International Congress on Acoustics - Eurogress, Aachen , Germany|
Duration: 9 Sep 2019 → 13 Sep 2019
|Conference||23rd International Congress on Acoustics|
|Period||09/09/2019 → 13/09/2019|
D'Antonio, P., Nolan, M., Fernandez Grande, E., & Jeong, C-H. (2019). Design of a New Testing Chamber to Determine the Absorption, Diffusion and Scattering Coefficients. In Proceedings of 23rd International Congress on Acoustics (pp. 2259-66). Deutsche Gesellschaft für Akustik.