So I take it that your telling me to setup the EQ using 80hz because it'll work for 40-50hz too. Also though, are you inferring that each preset doesn't have different EQ points, just possibly different crossovers, etc. The reason is that if I EQ for 80hz and use a bunch of EQ points for the area 40-80 could it theoretically not be as good for my stereo setup as setting up a separate 40hz EQ with all the EQ points at my disposal?

Ted