I have a 13.5 X 13.5' listening room and decided to bring up my JL Audio e110 sub from the basement HT system to hear what it sounded like. It helped greatly, so I bought a second sub and have no regrets. I do have DIY bass traps in all 4 corners now and the crossovers on the subs turned down, just filling in the bottom octave. The biggest impact in my system so far.