So like, since she used frequencies and shit- she should have headphones that A. Protects her human ears B. Provide sounds she can use in her battles, this way she has the sounds she actually needs in battles. I've been reading the manga and Hirokishi always adds practical tools and designs that make sense to help each heroes quirk. I always love reading his little tidbits about each costume for the heroes and villains. :0 Just throwing an idea your way to add headphones or some sort of ear piece you know.kinda rambling at this point