I think that's a pretty safe generalization for girl groups, and I don't just mean Asian.
Was listening to Nightingale in the car, and was wondering why it sounded so familiar. I think the reason is twofold. #1 -- the obvious one -- is that I've heard it before, because I bought it from The End/Omega; #2 -- and I'm not sure, but I think it's because he sounds like Rob Halford. The music is -- Colin, you're probably too young to realize this -- a little retro, too, and I'm thinking Judas Priest as well, but it might be something else, can't quite put my finger on it. If anyone knows, please share with me.
Colin -- if you haven't heard Sad Wings of Destiny and Sin After Sin, stop whatever you're doing, track them down now, and listen to them.