Four-Directional Ambisonic Spatial Decomposition Method With Reduced Temporal Artifacts

Abstract

For the creation of convincing virtual acoustics of existing rooms and spaces, it is useful to apply measured Ambisonic room impulse responses (ARIRs) as a convolution reverb. Typically, tetrahedral arrays offering only first-order resolution are the preferred practical choice for measurements, because they are easily available and processed. In contrast, higher order is preferred in playback because it is superior in terms of localization accuracy and spatial clarity. There are a number of algorithms that enhance the spatial resolution of first-order ARIRs. However, these algorithms may introduce coloration and artifacts. This paper presents an improvement of the Ambisonic Spatial Decomposition Method by using four directions simultaneously. The additional signals increase the echo density and thereby better preserve the diffuse sound field components during the process of enhancing measured first-order ARIRs to higher orders. An instrumental validation and a series of listening experiments compare the proposed Four-Directional Ambisonic Spatial Decomposition Method to other existing algorithms and prove its similarity to the best algorithm in terms of enhanced spatial clarity and coloration while producing the least artifacts.