The Effects of Simple Coupled Volume Geometry on the Objective and Subjective Results from Nonexponential Decay

This project focuses on the individual and interactive acoustic effects of three architectural parameters on the double slope profile from a simple coupled volume system created in the computer modeling program ODEON. The three variables studied are the volume ratio between the main and secondary spaces, the absorption ratio between the two spaces, and aperture size. The resulting energy decay profiles are analyzed using T30/T15 coupling coefficient ratios and Bayesian analysis. Coupling coefficient results show general trends in the effects of the three architectural parameters that match previous research results and the predominant interactive effect between the three variables involving a large coupled volume. Similar results are suggested by the Bayesian analysis based on the newly developed quantifiers, decay ratio and dB, although a more complex relationship among the variables may exist at larger volume ratios. A subset of the simulated sound fields have been auralized and used to conduct psychoacoustic testing. The subjective testing results indicate that perceived reverberation increases with greater coupled volume size and aperture size, correlating well with objective results. The outcomes also suggest that higher perceived reverberation coincides with larger decay ratios and smaller dB values. Subjective results based on clarity showed no significant effects. © 2005 Acoustical Society of America. DOI: 10.1121/1.1984892