For the size of your listening area, I'm sure the EP125 will be fine. I bought a HSU STF-2 a few weeks ago on impulse, thinking it would be a no-brainer upgrade to the EP175. Now I'm starting to be less impressed. CAVEAT - IN MY LISTENING ENVIRONMENT - the HSU seems to exhibit a little less control. It's almost overkill for the room where the EP175 seemed to blend in better. I'm going to play around with both for a few more weeks before deciding which one to keep.
Back to your question, though. I'm in a similar sized room (11' x 16'), and the EP175 never had to be turned past 9 o'clock. I'm sure the EP125 will be fine in your room.
