 An advantage of the Relational Event Theory over the Located Event Theory is that the former provides a criterion for specifying which among vibratory events at a source are sounds, namely, those that create medial disturbances that are (or can be) heard. The Located Event Theorist can, on the one hand, observe that the minimal requirement of a metaphysics of sounds is to specify which type of entities are sounds, and not, more specifically, which, among entities of that type, are sounds. Thus she would claim that sounds are events at a source, without caring to discuss whether some events at a source are not sounds. On the other hand, she can observe that too much fine-grained a classification would create a problem with those events that share with sounds all interesting metaphysical properties except for the property of being audible; a problem which, incidentally, affects a number of physicalist reductions of sounds.