Randy. You may have done this already but if you haven't go back and check your sub and speaker SPLs with your metre. That is always a good thing to do anytime you change something in your system...and you have made many changes. From the looks of your graph you may need to raise volume on your sub a couple of db to level match them.

You could go with an equalizer but only if you are through experimenting with placement and acoustical treatments. Before trying equalization, a second sub would be my suggestion albeit the equalizer is a cheaper option.

John