Tyre-road interaction noise is one of the sub-sources that constitute the vehicle as a noise source. Its relative importance is growing as modern vehicles develop, as in the case of electric vehicles. Impact noise is the predominant mechanism at low speeds in situations where obstacles are encountered on the road. For this reason, a model is presented that combines a dynamic analysis using finite elements method and an acoustic analysis using boundary elements method to study these circumstances. The dynamic analysis simulates a quarter of a vehicle by means of a 3D tyre on which a lumped model with mass, spring and damper is placed. This analysis generates the contact against the obstacle. The vibration produced on the tyre is used as a sound source in the acoustic analysis in order to study the sound propagation from the appropriate boundary conditions.