why are two subs harder to place than full range?

You can EQ a room to death and still have bad sound.
Take the case of a room with dimensions which are even multiples of one another.....say 8foot ceiling with 16x24 foot floor size. NO amount of EQ will get you away from all sorts of standing wave problems.
HSU (Dr.) recommends near-field sub placement. Right next to you, if possible!
The Harman White Paper recommends 2 subs, placed assymetrically. If anyone is interested, I'll find the link.
My personal listening space is a very odd shape. 8 walls, some at a 45, and a vault ceiling, also not symetric. My sub is near the mains, up against a side wall (the longest wall) and about 4 feet from the corner. Downfiring sub, with the port facing backwards. Decent integration, and with the X-over at 40hz, quite seamless with my Maggies. The room is well over 5000ft3. This is the right way to measure a room, since for any given floor space 8' vs 12' vs high vault ceilings will make quite a difference.

iplaynaked offers the best first cut for my situation, and i appreciate the advice. if that doesn't seem to work i'll wait for my back to heal and start moving some furniture and listening to the sub in different positions. btw. my room is about 14'x 23' with 12' vaulted ceilings. i'll be using a pair of tekton design fostex 167e single driver speakers on the short wall and two cheap aural ecstasy subs (i expect not to turn them up very much) listening at approximately 9 feet away. thanks again everyone.

magfan, in my last apartment that is almost exactly where i had my, at the time only one sub, and in the much smaller room i had huge bass with almost no volume (xover @ 60hz) and what seemed good integration (at least it didn't seem to take away from the sound of the tektons running full range, just an addition of lower frequencies).

First get a dolly so you can easily roll it around. In most rooms, deep bass does not couple in the same plain as the mids/highs. If you notice, most really expensive speaker systems have separate subs and a XO

If you use one sub, try to place it on the right side. NOT IN A CORNER.

The wringing of the hands is worth it

GOOD LUCK

Whatever works in THAT particular room.
/ listen / move sub / listen some more.
repeat until satisfied. Than leave it alone
for a while.

btw, here is something some of you may not already know concerning the use of subs with t-amps http://www.audio-magus.com/help_answer.asp?ID=20#135

although i didn't know this and connected speaker level anyway, my amp seems to have not suffered damage.