Verification of prediction based on randomized tail‐corrected cone‐tracing and array modeling

Abstract

A new room acoustics prediction method, randomized tail‐corrected cone‐tracing (RTC), is described together with sample prediction/measurement comparisons. RTC is the result of ten years of experience using the image source model, ray‐ and cone‐tracing, and combines elements of all three methods. RTC is a robust number‐prediction method, including the effects of frequency‐dependent diffuse reflection for both early and late reflections, as well as a method that creates echograms suitable for binaural post‐processing and auralization. Further, a WIN32 DLL directivity interface (DDI) is described. The interface is general and is capable of arbitrary data‐format translation and accurate distance‐dependent high‐resolution array modeling including beam steering. The array modeling is either made via a generic DDI module or via modules custom designed based on detailed manufacturer array specifications (transducer placement, directivity pattern, aim, weighting filter, and delay). Sample prediction/measurements comparisons are given for DSP‐controlled column arrays under free‐field conditions, in a large railway station and in a large church. It is demonstrated that the common fixed measurement distance 10‐deg full space data is insufficient for modeling arrays both due to the limited angular resolution and because far‐field conditions may not be reached until 30 m distance or beyond.