An immersive audio system was designed and implemented in a brand shop of a musical instrument retailer, along with the production of spatially expressive content. The system incorporates both sound image control and reverberation control technologies, providing visitors with an engaging and immersive auditory experience. In the content production, spatial impression was intentionally shaped by controlling the directional characteristics of reverberant sound through spatial weighting of level and delay parameters across a multichannel loudspeaker array. To verify the effectiveness of this approach, a preliminary evaluation was conducted in a laboratory setting, and the findings were applied to on-site system calibration. For the evaluation of reverberation directivity, energy-decay deviation (EDD) was calculated from impulse responses captured using a first-order ambisonic microphone. Numerical simulations suggested that EDD can serve as a useful metric for assessing the spatial characteristics of reverberant energy. Experimental results further demonstrated that directional weighting of level and delay allows for controllable manipulation of EDD values. This study reports on the acoustic design and tuning methodology for immersive spatial impression control and discusses the potential of EDD as an evaluation index for directional reverberation in immersive audio applications.
Ohgi et al. (2025) studied this question.