It has been more than a couple of decades since the interest in coupled volume systems started to grow rapidly among researchers. Basically, due to their increasingly popular applications in music halls for providing a rich acoustical environment either to fulfill the competing criteria of clarity and reverberance or simply to tune the auditoriums for multi-functional use. A lifelong experience with coupled spaces is the main motivation behind this paper. The journey starts with further developing the theoretical knowledge through scale model experiments. The results of which are utilized to observe the effects of the aperture size and shape on non-exponential sound energy decay by applying Bayesian analysis. The investigations have continued by field tests of real-size architectural monuments, specifically, worship spaces with multi-volume and domed typology. The relation of non-exponential energy decay and architectural parameters, for different scenarios or original uses of historical buildings, are searched through energy flow decays by applying the diffusion equation model. Simultaneously, all of these findings from academic research have been a source to produce acoustical design solutions for either small sized recording studios or large-scale multi-purpose auditoria in landmark buildings, all of which are briefly exemplified within this study.