Understanding the effect of room parameters on acoustic time reversal

Abstract

Time Reversal (TR) is a technique used to focus an acoustic signal at a particular point in space. Of the many variables that contribute to the quality of TR focusing, the most important are the number of sound sources, signal bandwidth. and properties of the medium. Although much research has been done to quantify the effects that the number of sound sources and signal bandwidth have on the TR process, little has been done in regard to the effect that room parameters have on TR. This is largely due to the difficulty involved with changing room acoustic parameters to measure their effects. We use the image source method (using the algorithm proposed by Allen and Berkley) to simulate the TR process in a variety of rooms with different acoustic and geometric room parameters. We define and calculate the maximum focal amplitude, the temporal focus quality and the spatial focus quality for each simulation. We compare the results and determine the effects of absorption and room volume on TR. We find that less absorption improves max response and spatial quality while it decreases temporal quality and that larger volumes have decreased max response and spatial quality while having increased temporal quality.Time Reversal (TR) is a technique used to focus an acoustic signal at a particular point in space. Of the many variables that contribute to the quality of TR focusing, the most important are the number of sound sources, signal bandwidth. and properties of the medium. Although much research has been done to quantify the effects that the number of sound sources and signal bandwidth have on the TR process, little has been done in regard to the effect that room parameters have on TR. This is largely due to the difficulty involved with changing room acoustic parameters to measure their effects. We use the image source method (using the algorithm proposed by Allen and Berkley) to simulate the TR process in a variety of rooms with different acoustic and geometric room parameters. We define and calculate the maximum focal amplitude, the temporal focus quality and the spatial focus quality for each simulation. We compare the results and determine the effects of absorption and room volume on TR. We find that less a...