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Empirical prediction and auralization of noise levels and reverberation times in industrial workrooms

University of British Columbia

Cost-effective noise control in industrial workrooms may be achieved by predicting and auralizing the soundfields generated by sources (e.g. equipment and fans) in the presence of candidate acoustical treatments. Prediction techniques available to noise-control practitioners range from computationally intensive but accurate ray-tracing and method-of-images models to simpler, but less accurate, models based on diffuse-field theory and empirical models. The auralization of industrial noise may be useful in demonstrating its negative effects. Auralization (acoustical virtual reality) systems range from cheap but grossly inaccurate stereo systems to very expensive but accurate digital-signal-processing engines. A combined noise prediction and auralization system for industrial workrooms - PlantNoise" - that bridges this cost-performance gap is presented here. New empirical noise-level and reverberation time prediction algorithms based on measured sound propagation curves and reverberation times are developed. Prediction accuracies approach those of the more complex models while calculation times are negligible. Auralization of the predicted noise levels is effected on an IBM-compatible PC equipped with a soundcard and headphones. Pink noise is generated at the same sound pressure level and frequency content as the predicted levels (in octave bands from 125 Hz to 4 kHz), and then presented to the system user over the headphones. The user experiences the predicted soundfield (updated in real-time) during a computer 'walk-through' of the virtual workroom. A graphical user interface enables visualization of the workroom floor plan, including sound sources and user position. Predicted octave-band reverberation times and noise levels are displayed on the screen. The total noise level at the user position is also displayed in dB or dBA. A contour map of the total noise levels is displayed on the workroom floor plan at the user's request.

Thesis/Dissertation

application/pdf

2009-03-11

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http://hdl.handle.net/2429/5875

Mechanical Engineering

University of British Columbia

UBCV

DSpace