Results from a detailed investigation into the eect of modeling assumptions used with the RSI method to compute broadband interaction noise downstream of a turbofan engine’s fan stage are presented. The modeling assumptions that are considered include the use of a Green’s function to obtain the exhaust noise from the unsteady vane surface pressure, the implementation of a 2D vs. 3D vane model, and the form of the turbulence velocity correlation function. Calculation of the duct acoustics via the Green’s function is shown to be robust when one selects the frequencies used for the calculation such that they do not coincide with a duct cut-on/cut-o edge frequency. The unsteady vane response calculated by strip theory is found to be dierent than that predicted with a three-dimensional vane model. However, it is not clear yet how these dierences specically impact the predicted exhaust noise. Inclusion of the inhomogeneity of the turbulence across the passage is not so important because the average passage value provides good results. The form of the correlation function used to model the inow turbulence is shown to have a strong impact on the overall sound power level. Within the RSI framework, it is shown that using a common 3D spectrum (e. g. Liepmann and Gaussian spectra) but disregarding the k3 contribution gives results 20 dB lower than when the nontraditional RSI spectrum is used. The inclusion of the k3 eect with the common 3D spectrum within RSI leads to a dierence of 10 dB