This work continues the analysis of data obtained during a 2017 NASA DGEN Aeropropulsion Research Turbofan ( DART ) core / combustor - noise baseline test in the NASA GRC Aero - Acoustic Propulsion Laboratory ( AAPL ) . The DART is a cost - efficient testbed for the study of core - noise physics and mitigation . Acoustic data were simultaneously acquired using the AAPL overhead microphone array in the engine aft - quadrant farfield , a single midfield microphone , and two infinite - tube - probe sensors for unsteady pressures at the core - nozzle exit . The data are here examined on an 1/3 - octave basis as a first step in extending and improving core - noise prediction capability .