This paper describes physical and digital design strategies for the Feedback-Actuated Augmented Bass - a self-contained feedback double bass with embedded DSP capabilities. A primary goal of the research project is to create an instrument that responds well to the use of extended playing techniques and can manifest complex harmonic spectra while retaining the feel and sonic fingerprint of an acoustic double bass. While the physical con figuration of the instrument builds on similar feedback string instruments being developed in recent years, this project focuses on modifying the feedback behaviour through low-level audio feature extractions coupled to computationally lightweight filtering and amplitude management algorithms. We discuss these adaptive and time-variant processing strategies and how we apply them in sculpting the system's dynamic and complex behaviour to our liking.