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Project Room acoustics modelling using 3-D digital waveguide mesh structures 

Physical models of sound propagation can provide perceptually accurate acoustic simulations, as all wave propagation phenomena – reflection, diffusion, absorption, refraction, diffraction, interference – are automatically considered.  Digital waveguide mesh models fall into this category and are an implementation of finite-difference time domain (FDTD) numerical solutions of the wave equation.

Waveguide modelling is computationally more efficient than conventional FDTD; 1-D and 2-D versions have been successfully applied to sound synthesis and acoustic instrument simulation.

This project explores the practical application of 3-D waveguide meshes in the accurate simulation of the acoustics of an enclosed space.  In 3-D, the size of the problem is increased by several orders of magnitude. Particularly efficient model implementation techniques are required in order to achieve reasonably short computation times.

Project areas of particular interest:

  • Model parallelisation – The application of crowd computation with data decomposition using the PVM software on both multiprocessors and workstation clusters.  Further work is planned using  specialised hardware.
  • Mesh topology optimisation – Performance comparison of 3-D rectilinear and tetrahedral models.
  • Efficient mesh configuration from Computer Aided Design (CAD) room data – The development of an automated procedure to configure mesh nodes directly from geometric room data obtained through rasterisation of 3D model slices - together with Department of Archaeology.
  • Model validation – Development of initial objective and subjective validation tests.
  • 3D mesh visualisation – using OpenGL to allow direct observation of the effects of the spatial discretisation  process.
  • Application to the acoustic reconstruction of ancient buildings – The selection of appropriate case studies - due to their intriguing acoustic properties, small size and irregular configuration, Neolithic chambers like Newgrange or Camster Round are particularly interesting.
Associated Projects: Links:

Staff Guilherme Campos, Prof David M Howard, Dr Damian Murphy

Funding FCT – Fundação para a Ciência e Tecnologia (programme PRAXIS XXI)