Investigation into the Perceptual Effects of Image Source Method Order

This engineering brief explores the perceived effects and characteristics of impulse responses (IRs) generated using a custom, hybrid, geometric reverb algorithm. The algorithm makes use of a well known Image Source Method (ISM) and Ray Tracing methods. ISM is used to render the early reflections to a specified order while ray tracing renders the remaining reflections. IRs rendered at varying ISM orders appear to exhibit differences in perceptual characteristics, particularly in the early portion. To understand these characteristics, an elicitation test base was devised in order to acquire terms for the different characteristics. These terms were grouped in order to provide attributes for future grading tests.