The interactions between adjacent rotors induce intricate and unsteady airflow in their vicinity, directly influencing both the aerodynamic efficiency and acoustic emissions of the multi-rotor UAVs. This interaction is appreciably influenced by the spatial distance between adjacent rotor tips. In this study, the aerodynamic noise characteristics of APC quadcopter rotors with the different separation distances between neighboring rotor tips and with the different rotational speeds of multi-rotors in hover were investigated. We employed the unsteady panel method and acoustic analogy, solving the FW-H equation using formulation Najafi 1C.