Systematic Evaluation of Perceived Spatial Quality

Evaluation of the audio quality a listener perceives is an important issue for all those involved in audio recording and reproduction. The variety of tools in audio work facilitates advanced processing of the audio signal. The aims of these processes differ, but they all in some way, sooner or later give rise to the question of in which way the audio quality is influenced by them. The use of multichannel techniques for both recording and reproduction has given many listeners the opportunity to listen to surround sound. New systems open possibilities to new experiences for the members of the audio community, both technically and creatively. Surround sound systems are no exception. But what are these experiences? What can a listener perceive? How can the perceived sensation be described? How can it be ‘measured’? The answer to these questions could be expressed as the audio quality of a surround sound system. In two-channel stereo, a listener can perceive locations and distances of sound sources. These are descriptions of where sources are positioned; perhaps even how wide they appear to be. Such properties of the perceived sound are referred to as spatial characteristics, or all together as spatial quality. How can we describe spatial quality? How can we evaluate it? What forms the spatial quality of a surround sound system? These questions are addressed in this paper, where a novel method for evaluation of spatial audio in surround sound systems is presented, and also some results of using such a method. 1 BACKGROUND