A music performance data signal contains tone effect control messages to control the tone signal processor for imparting tone effects to the produced musical tones in a high-ranked model of tone producing apparatus in which many and complicated tone effects are available. In order that such a music performance signal can drive a low-ranked model of tone producing apparatus in which a small number of and simple tone effect are available, the tone effect control messages for the high-ranked model are converted to tone effect control messages which can realize similar tone effects as on the high-ranked model. For the tone effects not directly available in the low-ranked model, the tone effect control messages are converted with reference to conversion tables.