I can’t speak to the ocarina but a violin??? It’s an instrument infamous for screechy off sounds. Those are caused by unexpected friction on the strings amplifying or even making harmonics dominant. The most prominent sound wave may mimic a sawtooth because of the mechanics of a bow (I don’t know, just trusting you on this), but every bit of loose fiber on the bow and every inconsistency in rosin and every physical variation on the surface of the string can produce harmonics before any sound hits the curves of the body, which produces yet more.