A music apparatus has a set of controls manually operable to input a performance event, a waveform memory storing an original waveform sample composed of a series of digital values sequentially readable from a default start address, and a processor for executing a tone generating process in response to the performance event. The tone generating process is executed by the steps of scanning the original waveform sample to determine a set of variational start addresses which are diverging from the default start address and which are allotted to corresponding ones of the controls, detecting an operated control among the plurality of the controls, specifying one of the variational start addresses corresponding to the operated control upon detection thereof, reading the original waveform sample from the specified variational start address to provide a variational waveform sample which is diversified from the original waveform sample uniquely to the specified variational start address, and synthesizing a musical tone unique to the operated control in accordance with the provided variational waveform sample and in response to the performance event.