PRISM – 3D Acoustic Model

Acoustic Model Algorithms

2018 should finally see the release of the PRISM acoustic software. The following page provides some background information on the software, and future innovation.

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PRISM is a hybrid numerical and geometrical, 3D acoustic model. It can be used to predict acoustical parameters used in room acoustics. Once the results have been calculated, detailed visualizations can be shown.

Empirical methods

Empirical methods are employed in simple spaces by acoustic consultants, architects and other professionals.  They can provide quick estimates for the reverberation time of a space.

Results obtained from empirical methods are less accurate than other methods and are usually used in rooms with simple geometry.

Geometrical methods

These methods create sound ‘rays’ or ‘particles’, which are subject to the laws of reflection. Ray-tracing and image source models can often provide more accurate results. They are useful in rooms which have complex geometry or an uneven distribution of absorption.

While geometrical methods are accurate in a number of cases, they can give less accurate results when used in small rooms, or when assessing low frequencies. Wave effects such as diffusion are not accounted for, and consequently work rounds may be required. 

Numerical Methods

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For years numerical calculations methods (FDTD, FEM, BEM, etc) have been used to solve big problems in physics. Some ares in of study are: Thermodynamics, Electromagnetics, Fluid Dynamics, and of course acoustics.

Numerical models solve partial differential equations, making them potentially very accurate. PRISM-RA uses the 3D FDTD method for its calculations and therefore has the potential to be one of the most accurate pieces of room acoustic software available.

The software is unique when compared to existing room acoustic software. New parallel processing techniques allow the software utilize hundreds of GPU cores available to most modern graphics cards.

Ultimately this means that numerical calculations can be carried out in a reasonable amount of time, without the need for a super-computer!