The apparatus involves a hand-held housing with a memory for storing coded audio event data, a mechanism for downloading into the memory coded audio event data and digital-audio electronics for retrieving coded audio event data from memory, converting it to an audio signal and playing it out. In one disclosed embodiment of the invention, the data are stored in accordance with a musical instrument digital interface (MIDI) standard, and may be created on an appropriately equipped personal computer (PC). The capacity of such a hand-held device is far greater than if the data were conventionally digitized or coded. A wirelessly networked system of such music devices in physical proximity is disclosed that enables audio score synthesis and mixing by at least one such device of a synthesized score and an inputted score for outplay to others in a real-time musical jam or music-sharing session.