Sound analysis software applications have become commonplace for exploring music and audio, and important factors including responsive/fast data visualization, flexible code development capabilities, availability of standard/ customizable libraries/modules, and the existence of large community of developers have likewise become integral. The widely used MATLAB software, in particular, has played an important role as an all-purpose audio exploration and research tool. However, its flexibility and practicality when exploring large audio data, its limitations for synchronized audiovisual exploration, and its deficiencies as an integrated system for audio research is an area that can be improved. In this paper we report on developments on the Sound Analysis Toolbox (SATB), a pure MATLAB-based toolbox that addresses some of MATLAB's basic deficiencies as an audio research platform. We introduce solutions including efficient visualization for literally any sized data, a simple feature extraction "plug-in" API, and the sMAT Listener module for spatiotemporal audio-visual exploration.