an electronic musical instrument comprising a host processor , process / engine interface and sound engine the latter utilizing partial control chip modules and a data path chip module to effect multiple partial synthesis , in conjunction with a sound modelling technique , to generate up to 240 independent partials and impress time - varying amplitude envelopes on them and select and apply them to sound generation , each partial being controlled by selected parameters of frequency , amplitude , phase and attack / decay rate . a modulo - sumdither and oversampling approach to noise reduction is utilized in connection with the data path chip arrangement . log sine addition is utilized to avoid multiplication apparatus ordinarily required to combine sine wave defining parameters .