In this section
@inproceedings{Antonello:2015,
author = {Antonello, N and van, Waterschoot T and Moonen, M and Naylor, PA},
pages = {185--190},
title = {Evaluation of a numerical method for identifying surface acoustic impedances in a reverberant room},
year = {2015}
}
TY - CPAPER
AB - Wave-based room acoustic simulations are becoming more popular as the available compute power continues to increase. The definition of boundary conditions and acoustic impedances is of fundamental importance for these simulations to succeed in representing a realistic acoustical space. Acoustic impedance databases exist in terms of absorption coefficients, which are usually measured in reverberation chambers. In this type of measurements, the sound field is assumed to be diffuse, a condition which is not met in most rooms. In particular at low frequencies, where wave-based simulations are possible, a different approach is sought as an alternative to acoustic impedance measurements. This paper focuses on a recently proposed method for estimating surface acoustic impedances. This method is based on the use of a numerical room model, and does not require the assumption of a diffuse field. Assuming that the geometry of the room is known, a finite difference time domain (FDTD) simulation is matched with measured data by solving an optimization problem. The set-up for such a measurement method consists only of a set of microphones and a loudspeaker. This could be applied in every room, removing the need for expensive facilities such as reverberation chambers. The solution of the optimization problem leads to the sought parameters of the acoustic surface impedances. In this paper the adjoint method is used for the computation of the derivative in the optimization problem. This method enables a large number of decision variables in the optimization problem making it possible to account for inhomogeneities of the surface acoustic impedance and hence to avoid the need to specify the different acoustic impedance surfaces beforehand.
AU - Antonello,N
AU - van,Waterschoot T
AU - Moonen,M
AU - Naylor,PA
EP - 190
PY - 2015///
SP - 185
TI - Evaluation of a numerical method for identifying surface acoustic impedances in a reverberant room
ER -
Speech and Audio Processing Lab
CSP Group, EEE Department
Imperial College London
Exhibition Road, London, SW7 2AZ, United Kingdom