I am surprised no one mentioned that he really should be checking to see if where he has the sub is optimal. Many times, users have come onto the forum complaining that the EP500/600 is not "blowing them away". However, depending on your room, you may need to use the "sub crawl technique" for optimal placement.
Put the EP500 where you would normally sit (you will have to move your couch). Now play some bass heavy music and crawl along all your walls to see where the cleanest and loudest sounding spot is for LFE. That is where you want to put your sub.
Try it all over again, it should make a huge difference. If you do not want to do that, try walking around your room, or sitting in different spots, some spots will have more bass than others, this will tell you if the sub is working correctly.
