Reproducibility of a metric for sound reflectivity

Past attempts at developing a system able to quantify the sound reflectivity of a surface have been hindered by the shear difficulty of repeatability and reproducibility. Where and why these challenges arise, and how they can be overcome is discussed. Sound fields resulting from direct sound energy projected at various incident angles toward materials and assemblies are compared as well as how laboratory setups and specimen changeovers can affect outcomes. Can precision be increased and bias avoided? A proposed system based on software driven microprocessors and robotic precision is very fast with a high degree of precision performing at less than 0.1 mm error over 50 repeated runs. The performance in terms of repeatability and reproducibility are approximately equivalent to today's ink jet printers. As a recognized acoustic metric, the Sound Reflectivity Index could provide vital data that would accompany all products. For acousticians, a higher order of accuracy would be possible in designs involving en...