A numerical study using our source code to acquire the acoustic properties of subsonic flow past an open cavity with different modified geometries will be presented in this paper. A Modified Curie's analogy will be applied to solve the far field acoustics of the flow. Several cases with different leading edge of cavity fillet radii will be analysed and the effects will be investigated. It is important to find a way to attenuate the sound generation by the cavity, as it is an undesired situation for most applications. In this work a passive system, fillet modification,to the leading edge of the cavity, is suggested and the effects of it on the sound generation is investigated.