If god permits, next year i'll be in pharmacy school living with and leeching off my aunt/uncle. I hope to put a HT setup in and will use the subs i already have (for a start). My question is which should i use. I have the two 15" atlases and the 1 15" avalanche. I'm not sure how much different HT is from car audio, so i'll put my speculations and you all can feel free to correct me.

two atlases will have more than enough output i'm sure. But won't get as low as the Avalanche. The avalanche will get low, but not as much output. Also I imagine an amp for the atlases would be easier to come by. (300W @ 4ohm vs 800W @ 4ohm)

So my question is for HT is lows needed more than output (this will be for movies, i want realistic sound, not my bass crazy car. And should i worry about either not having required output? (for a car this would be a stupid question since both setups were loud in car, but i don't see cabin gain helping me in a big open room)

Depends on how big the room is

An Onkyo 8" sub suits my HT just fine. Its a fairly small room so i dont need a 15 for LFE.

the exterior of the house is 36 x 36, this room is almost completely open, i'd say 30 x 30 at least :-/

I'd go with the multiple drivers corner-loaded with as much power as you can afford. Elias is right on track with the room size. And don't be mistaken that the AVA will have more lowend than the Atlas. It's all dependent upon application and room characteristics.

Smaller drivers properly applied can have extraordinary effects in the LFE department.

i'd like to avoid buying new subs, just use what i already have, so i'm guessing the two atlases would be better suited? Thats good news since i had originally planned on using them.

I love a good EBS alignment. Big enclosure, LOW tune. Great efficiency and an exagerrated low-end with a trade-off for mostly poor musicality. Not always though.

square rooms are really bad for HT applications

EBS???

and in all honesty the room is rectangular, i was just giving quick ideas, all the rooms are located on one side of the house so you end up with a slimmed down rectangle, i have no idea how much, whatever a normal room width is, lol

Let me do a crappy paintshop drawing...

http://i2.photobucket.com/albums/y50/vladd06/room.jpg

The offsets are taken, one for a semi-office the other has the uncle's architecture(Sp?) stuff. the bed is on the left side of the room, (between the left offsets) and the tv is in the upper right. The tv is moveable, but the bed isn't.

something like this is possible...

http://i2.photobucket.com/albums/y50/vladd06/room2.jpg

1 aa atlas tuned low would sound quite nice in ht.imo that would be my choice not to mention ht doesnt normally need a ton of bass.all in your preference. good luck

My bro DL'd some nice HT dvd's

They are pretty through on subwoofer/speaker placement.

It really varies on the rooms dimensions.