whether the voice is incorporeal. what is it that the gives echo?

pythagoras, plato, and aristotle declare that the voice is incorporeal; for it is not the air that causes the voice, but the figure which compasseth the air and its superficies having received a stroke, give the voice. but every superficies of itself is incorporeal. it is true that it move with the body but itself it hath no body; as we observe in a staff that is bended, the matter only admits of an inflection, while the superficies doth not. according to the stoics a voice is corporeal since everything that is an agent or operates is a body; a voice acts and operates, for we hear it and are sensible of it; for it falls and makes an impression on the ear, as a seal of a ring gives its similitude upon the wax. besides, everything that creates a delight or injury is a body; harmonious music affects with delight, but discord is tiresome. and everything that moved is a body; and the voice moves, and having its illapse upon smooth places is reflected, as when a ball is cast against a wall it rebounds. a voice spoken in the egyptian pyramids is so broken, that it gives four or five echoes.