Modal PD state active control applied to a simplified string instrument

This study proposes an application of modal active control on musical string instruments. Its aim is to control the modal parameters of the soundboard in order to modify the sound of the instrument. Using both state and derivative state modal control, a method is given, from the modeling of the active structure through to the design of the control system. Issues such as the identification of the structure's characteristics or the stability of the control system are dealt with for this original control method. Then, this technique is applied on a model of a simplified string instrument soundboard. Time simulations are conducted to study its effect on the instrument vibration. They show that, thanks to soundboard modal active control, it is possible to modify the amplitude of the sound harmonics to change the timbre as well as the sound level of the instrument.