I've never built a speaker before so I have no prior knowledge on the specific details of building a sub. I am looking to upgrade my current 23W 6 inch Sony sub to one that will let you FEEL an explosion or a T-rex running by, not just hear it. However, my budget is rather limited. Thus, I wanted to know how much of a difference a sub whose max low freq. is 20 Hz would be from a sub whose max low freq. is 15 Hz. I was browsing through a Crutchfield catalog and I was looking at the car audio subs, boxes and amps and I'm wondering if I can just purchase a preassembled box like they use in cars for a sub and add a sub and amp? If I can, I was looking at the Pioneer TS-W384DVC 15" http://www.crutchfield.com/S-BFNtcB1...mp.asp?g=67800 or the Sony XS-L1536. They are both the same price ($160), but the Pioneer has a max freq. of 15Hz w/a natural resonance of 21Hz vs max freq of 18hz and a natural resonance of 23 Hz for the Sony. If there is little noticeable difference between 15 Hz and 20 or 25Hz, I would rather save some money and get a cheaper 20 or 25 Hz sub or just buy a premade home theater sub (I was recommended the AudioSource SW 15, a 15" 200W 25Hz max low freq. sub). All other things being equal, would a 500W 25Hz sub sound tighter than a 200W 25Hz sub and thus it is the max power that makes a difference in the very low freq? Another question would be the type of amp to get. Should I just looking for a mono channel that will handle the max wattage of the sub and allow you to adjust the freq cut off or is it more complicated than that? I've heard people say one should have an equalizer for the sub to get rid of any excess boomeness, is that possible through the amp? Are there different amps for car audio vs home theater? The room I'll put this in is a small (25 ft long by 15 ft wide) room with three walls (front, back, one side) if that information makes a difference.