beeping?

when attacking enemys I sometimes get this weird whistleing/beeping sort of sound, and I have no idea what it is. What is it?

What version are you playing?

Also, what weapons do your characters have equipped?

I'm playing the nes version. maria has two sheilds, firion has a wing sword guy has a orge axe and reila has a wing sword and some kinda of spear. I think its happened when I used attack spells too.

Perhaps they're about to explode? I don't know, I've never had such problems

when consoles get old they start making weird noises. my snes was hilrious before it's untimely death. The funky noises and music started out being occasional, then constant, then it died.