Hypotheses for constructing a precise, straightforward, robust and versatile sound field reproduction system

The three dimensional sound field reproduction systems can be categorized mainly into two types, physical reproduction, and artistic reproduction. The former is sometimes referred to as scientific or engineering, and the latter is sometimes recognized as psychological reproduction using phantom images produced by, for example, amplitude panning and the other effects. The purpose of the reproduction system is widely spread. The system can be a design tool of enclosed space, such as a concert hall, before practical construction by reproducing physical characteristics accurately. Also, the system can be a pure entertainment tool, mostly with visual images. Of course, the scale and necessary conditions vary with their purpose and objectives; however, it might be interesting to investigate what are the essential factors for the higher total performance of reproduction systems. We currently hypothesize that the following four conditions might be necessary for the total performance of the versatile sound field reproduction system. A) physical accuracy, B) robustness against disturbance, C) flexibility for additional direction, D) capability of integration with visual stimuli. As a platform of examination, 24-channel narrow directional microphone array and 24-channel loudspeaker array are used. The boundary surface control principle and its modified version are adopted for the physical background. As examples, several practical efforts are attempted to assure the total performance of the system effectively.