Analysis of parameter effects on sound energy decay in coupled volume systems

This study focused on characterizing the effects of changing several architectural parameters on the sound fields generated in a particular type of enclosed space known as a coupled volume system. The architectural parameters investigated included the ratio of the main and coupled volumes, the ratio of the absorption in the two spaces, and the size of the aperture separating them. The level of Double Slope Effect (DSE), as given by several quantifiers, was determined for various configurations of the coupled volume systems based on these architectural parameters. Additionally, the human subjective response to the sound fields in these systems was investigated in this study. First, a simple coupled volume system consisting of two rectangular boxes connected through an acoustically transparent opening was constructed and studied using computational modeling methods. For this system, DSE decreased with increasing ratio of coupled absorption over main volume absorption. Also, DSE increased with increasing ratio of coupled volume size over main volume size, referred to as volume ratio. DSE values were maximized for aperture sizes that were a small percentage of the main volume\u27s total surface area. Testing of the subjective response to sound fields from this simple system showed an increase in perceived reverberance with increasing volume ratio and aperture size, while perceived clarity did not change by a statistically significant amount across any of the architectural parameters. A complex coupled volume system, typifying an average coupled volume concert hall was then computationally modeled to investigate in detail the effects of varying absorption ratio and aperture size on DSE. In general, DSE trends corresponded with those found in the simple coupled volume system investigation and with previous research. Subjective preference testing of this virtual hall showed that listener preference generally increased with decreasing DSE, and listeners preferred low and medium levels of DSE the most