Erm yeah... the epiks are known for their midbass so them not having a punchy sound is unusual. You should bring the sub a couple inches from that wall for starters so you are getting use out of both drivers. Small square rooms have terrible FR's usually unless you land your sub in the sweet spot from the get go, do the sub crawl. Put sub in chair as close to your ear level as you can, then crawl around the room while something bassy is playing and note where the output is strongest, this is the subs new home.
After that is done get a spl meter & rew and check to see whats going on with phase and your overall FR. If you opt not to go that route just adjust the phase until you note the strongest output. Tests are great but ultimately your ear is the judge. I calibrate my system flat then adjust to taste afterwards.
Edit: *doh* I probably would have just used a much cheaper software eq since it is hooked up to the PC. It'll definitely help you overcome the room at any rate.