I (efficient or sensitive?) do not want to need to get a 1k or 2k wpc amp. Could a line array be made as a triangle so it fits nice in the corner? I can do 1 possibly 2 for the dining room rear walls that are a max height of 10', and I can do 2 in the front corners too... my curtains will overlap about 4" though. Depending how much they come out from the wall... I might be able to go 12' tall. I am attaching a pic of a template I was going to use for a bass trap in the front corners.
My other option for a sub is on the side wall on each side of the couch. If I go there I could go 10', and still maintain making my bass traps for the corners too. To the right of the couch is my fireplace, but the sub could go next to it, and be lined up wih the couch. The fireplace sticks out 3' from the wall, and I have thought about putting acoustic panels on each side of the fireplace to stop reflections.
If I go with 12" woofers... what specs would be best for purchasing the woofers?
I am not in a big hurry... I will check out the local car audio store this next week. If they are too high or do not have what I need... I will import.
Sensitive or efficient?
if sensitive then I would suggest a pro audio driver. TH or FLH or simple ported all work well.
So what space are we working with to start?
If the columns up front then that is a tuff space for a single ported 12 because your using a sono tube. If building yours with MDF then going with a bunch of cheap 12's would work. Like a line array if you will. Maybe four per side. But your looking at maybe 92-94db sensitivity.
For hitting down low(20hz) you will need a lot of volume. Mainly because you have a large room. So when going with that direction you need about a pair of 18's to start. Then go from there. So just building the sono subs limits your spl. You could go up and down firing pair of 12's in a sono tube but this will be likely a sealed cabinet. So that means 20-30hz wil probably be not as loud as the single ported cabinet. BUT everything else would be louder.
I dont want to talk you out of any design you may have your heart set after. BUT line array style four 12's per side would be pretty nice to go along with K402's. The 12's can be ported or sealed and can be whatever car audio so long as you have T/S parameters. If and when you have a possible driver to choose I cab model for you. I will be home the next few days so I can model.