The intense noise radiated by supersonic jets leads to sound-induced structural vibration, fatigue and personnel-related operational difficulties. Experimental, theoretical, and computational investigations into the physics and control of jet noise have identified several important sound sources, including wavepackets, screech, Mach wave radiation, and broadband shock associated noise. Reducing the loudest sources of jet noise, without sacrificing propulsive performance, has relied on intuition, parametric survey, or optimal control techniques. With the aim of developing a more general and robust method of jet noise reduction, we present a physics-based approach that reveals jet dynamics/mechanisms, highlighted by a linear resolvent analysis, crucial to the the generation of jet noise in a biconical tactical jet nozzle. Our approach uses large-eddy simulation to predict the turbulent flow within and exhausted by the jet nozzle and then identifies optimal forcing/response modes of the compressible Navier-Stokes operator, linearized about a fully-resolved jet mean flow, to identify and manipulate coherent structures that are primarily responsible for the production of jet noise. The operating conditions of the jet and nozzle geometry are motivated by tactical Naval aircraft.