Perceptual studies on spatial sound reproduction systems

Author Nick Zacharov Title Perceptual Studies on Spatial Sound Reproduction Systems This study considers research on spatial sound perception in the context of multichannel and other spatial sound reproduction systems. Issues associated with multichannel level alignment are discussed. Additionally aspects relating to the quality of spatial sound reproduction associated with loudspeaker directivity and 3D sound algorithms are considered. Lastly, a study of spatial sound perception is unfolded. This thesis contributes to the understanding of level alignment techniques from both a subjective and objective standpoint in multichannel sound reproduction schemes. The aim of these subjective experiments was to obtain a database of subject responses for a level alignment task under a wide range of normal usage situations, accounting for different source locations, distances, directivities, sensitivities, bandwidths and absolute reproduction levels. The data was analysed and correlated with a set of objective metrics measured for each test condition. From this analysis it is possible to ascertain superior test signal/metric combinations for perceptually motivated level alignment. Results may be directly applied to automated level calibration systems. Tools for binaural real-time loudness measurement are introduced allowing for the assessment of directional loudness characteristics and multiple source loudness alignment within arbitrary reveberation spaces. The second set of experiments focuses on issues influencing the quality of spatial sound reproduction under different multichannel sound reproduction scenarios. Firstly, the influence of loudspeaker directivity is subjectively assessed in a discrete five channel multichannel scenario. A set of experiments are presented that assess the influence of directivity both in the frontal and surround loudspeakers under idealised listening conditions. A range of virtual home theater systems are reviewed and a benchmark experiment is presented that compares their performance with respect to a discrete five channel multichannel reproduction. Evaluations are performed in an idealised “standard listening room” and real room conditions. Relative performances of each system are discussed in terms of relative spatial and timbral degradation. Lastly, initial studies are presented into the multidimensional perceptual unfolding of spatially processed speech reproduced over headphones. This study provides the basis for further studies in this area in an attempt to unravel or “unfold” the perceptual dimensions associated with spatial sound reproduction. UDC 534.8:681.1