In this paper the aeroacoustic results using the Free-Wake Model (FWM), Vortex Particle Method (VPM), and Computational Fluid Dynamics (CFD) are compared with one another. The FWM and VPM is performed using the software Rotorcraft Comprehensive Analysis System (RCAS), and CFD analysis is performed using the software Helios. Analysis is performed on a lift-offset coaxial rotor system operating at 150 knots in forward flight and 0° shaft tilt. First, the blade loads are compared and then the acoustics using the noise prediction software PSU-WOPWOP. The major difference between the analysis methods is the manner in which they capture aerodynamic interactions. And the differences in the interactions result in differences in the acoustic results. The primary interactions are the blade vortex interactions (BVI), and the blade crossover interactions (BCI). The BVI events occur when a rotor operates in the wake of its own rotor or another rotor, and the BCI events occur when the blades of the upper and lower rotors cross one another. The BVI events are captured by all three methods, but there are variations in location and intensity between the three methods. On the other hand, the VPM and CFD capture the BCI events, but the VPM is unable to capture the BCI events on the retreating side of the upper rotor. These differences in the prediction of the interactions results in variations in directivity as well as intensity of the noise results. Upon analysis of the aeroacoustic results it is concluded that the inability of the FWM and VPM to capture some of the primary interactions capture by CFD can lead to major discrepancies between the acoustic results of the three methods.