Towards High-Quality Sound Synthesis of the Guitar and String Instruments Matti Karjalainen 1,2, Vesa Valimaki 1,2, and Zoltan Janosy 1,2,3 1 Helsinki University of Technology, Acoustics Laboratory Otakaari 5A, SF-02150 Espoo, Finland 2 CARTES (Computer Arts Center at Espoo) Ahertajankuja 4, SF-02100 Espoo, Finland 3 Technical University of Budapest, Department of Telecommunications Sztoczek u. 2., H-1111 Budapest, Hungary matti.karjalainen@hut.fi, vpv@vipunen.hut.fi, janosy@tsys.hit.bme.hu Abstract The sound quality of real-time synthesis based on physical models has so far been inferior to sampling techniques. In this paper we introduce new principles to make model-based sound synthesis of the guitar and other plucked string instruments more attractive from the viewpoint of sound quality. A major improvement is achieved by estimating the model parameters and the excitation signal from the sound of an acoustic instrument. It is shown that the impulse response of the body is included in this excitation. More complex string behavior, including nonlinearities in some instruments, is briefly studied. Furthermore, different aspects of controlling the real-time synthesis model are discussed. High-quality real-time synthesis is shown to be feasible by using a single digital signal processor.