Investigation on the Quality of 3D Sound Reproduction

Standard audio reproduction formats assume that the loudspeakers are positioned in the horizontal plane. The last missing dimension – height – offers many opportunities and challenges. In this paper we focus on one challenge, i.e., the evaluation of reproduction systems with additional height channels. First, the results of an expert survey regarding the importance of 3D sound for different applications are presented. Secondly, the overall quality of 3D sound reproduction is evaluated by listening tests. Because the selection of sound items is critical for the evaluation a broad selection of different sound items is used. To classify sound items, we extend an existing 2D sound categorisation concept to 3D. The test signals were derived from original 22-channel sound items. The 2-, 5-, and 9-channel sound items were generated by passive down-mixing algorithms and selective muting of reproduction channels. In addition, we investigate the influence of an external reference. Therefore, one listening test with a reference and a second one without a reference were conducted. A companion paper focuses on controlling physical relevant parameters of a 3D audio setup.