80-18kHz doesn't mean a thing until it is matched with the db figures for the same.
It could mean flat from 80-18k (very unlikely) it could mean 80-18k at -3db, it could mean 80-18k at -9db... (all utterly different in sound).
Don't let specs fool you. They are just like statistics. Easily bent to display what the vendor WANTS you to think.