This paper reports a new approach to modifying the sound produced by a wind instrument. The approach is based on modal active control, which enables adjustment of the damping and the frequencies of the different resonances of a system. A self-sustained oscillating wind instrument can be modeled as an excitation source coupled to a resonator via a non-linear coupling. The aim of this study is to present simulations of modal active control applied to a modeled self-sustained oscillating wind instrument in order to modify its playing properties. The modeled instrument comprises a cylindrical tube coupled to a reed and incorporates a collocated loudspeaker and microphone; it can thus be considered to approximate a simplified clarinet. Modifications of the pitch, the strength of the harmonics of the sound produced by the instrument, and of the oscillation threshold are obtained while controlling the first two resonances of the modeled instrument.