I definitely think solid doors and the magical protections would prevent cultists inside the compound from being affected. The ones outside within earshot could be affected, sure, if she stands far enough away to beat the Repellant effect that the walls have going on.

That being said, yes some cultists would definitely rush out to see what's happening, although they'd start to hear reports via radio that those remaining inside should STAY inside away from the singer. Of course, that'll only last so long. So I think Zelda would definitely get a significant number of cultists enthralled.