1. A tone generator apparatus comprising: a plurality of tone generating elements that define a plurality of channels for generating a plurality of tones in parallel manner; and a register that is divided into a first area and a second area for storing individual parameters provided individually for each of the channels in the first area, and storing common parameters provided commonly for two or more of the channels in the second area, wherein said tone generating element is constructed to use both of the individual parameter and the common parameter corresponding to the channel defined by said tone generating element for generating the tone specific to the channel and characterized by both of the individual parameter and the common parameter.