When I first ran my new HT, I had set the levels of my twin Velo 10" subs (nowhere near the EP500 in performance) to 4 out of 10. Later on, I mustered up the courage to run Audyssey from my Denon AVR & the results showed that Level 4 was way too high & was outside it's ability to correct it. After several more calibration runs of progressively lowering the subs' volume, Level 2.5 ended up being within Audyssesy's correction range.
My HT is now quite awesome for movies & wonderful for music without being over the top. This exercise proved to me that without a calibration system or an SPL meter, it is quite difficult to set the levels correctly by ear alone. I think that we generally tend to overdo it on bass levels because the sound is so impressive, but in reality it is actually overblown; however, some people like it that way.
For me, I find that too much bass produces annoying buzzes & rattles in my furnace/fireplace ducting inside my walls/ceilings that I would rather not hear...