This study aims to control the soundboard’s vibrational modes in order to modify the timbre of string instruments. These structures are wooden plates of complex shapes, excited by strings through a bridge. In order to apply an eﬃcient control on such systems, modal parameters must be identiﬁed using classic algorithms applied on experimental measurements. Then it is possible to design a feedback controller using these parameters and classic control methods. At ﬁrst, a simulation of the control has been done for a rectangular spruce plate, boundary clamped and excited by a single string. This simpliﬁed case and ﬁrst results in term of changes in eigenmodes are presented here.