In this paper we describe a synthesizer to be used both for vir- tual reality and musical purposes, based on an additive synthesis model, and that offers an intuitive control of impact sounds. A three layer control strategy is proposed for this purpose, where the top layer gives access to a control through verbal descriptions, the middle layer to a control of perceptually relevant signal descrip- tors, while the bottom layer is directly linked to the parameters of the synthesis model. The mapping strategies between the parame- ters of the different layers are described. The synthesizer has been implemented using Max/MSP, offering the possibility to manip- ulate the sounds in real-time through the control of the different parameters.