Is it modes or nodes? :o
Anyway, that's not my question... Here's the scenario:
Due to the shape of my basement, I have to put my couch pretty much right in the half way point between the front and rear wall of the room. I've heard that this is a no-no do to the fact that low frequency waves pretty much produce a void at that spot in a rectangular room with a flat ceiling (I haven't actually measured). When I stand a couple feet behind my couch to play foosball, the bass seems to be a little more punchy and just sounds 'better'. I have a Definitive PF 15TL Sub. It's not the quickest or sharpest sounding sub, but I love the low explosions, rumblings, and other effects that only a 15 seems to excel at. (in my price range anyway:) My room is in the basement, but the house is a split level so there's no walls or door dividing it from the upstairs. I have a "room optimizer" mic that the yammy receiver sets the bass with. I've attached a grainy picture of my setup.

So, here's my question(s):
Will positioning my sub elsewhere in the room help the bass at my listening position on the couch? If so, where should I start placing it to see what sounds good? Behind the couch? On a side wall? Is there anything I can do short of building a dedicated room that will make my bass sound a little better? Does my PF 15TL Sub just suck ass? I thought it sounded good when I auditioned it at the HT store.

Thanks for your advice!
-Shawn

the TL line was a failure, it's when they started porting their subs and using cheaper drivers

the TL line came and left pretty quickly

the 15TL is still an "OK" sub for the money

definitely play around with placement, especially since it's ported in the rear

it looks like you should get that center speaker down lower if you can

Different placement of the sub should help. The quickest and simplest way to get an idea where would be to put the sub at your listening position then crawl around the room, listening to something with a good bass track you know well and see where it sounds the best to you. That's where the sub should go.

the TL line was a failure, it's when they started porting their subs and using cheaper drivers
Man, that sucks.

it looks like you should get that center speaker down lower if you can
I wanted to put it under the tv, but all the stands I could find with a space for a center channel were super expensive. Maybe I should modify my stand and take out the top middle drawer for the center channel...

put the sub at your listening position then crawl around the room
My wife will think I'm crazy, but that's an awesome idea! Thanks!

Does the fact that the sub is sitting on a concrete floor in my basement make any difference, and is there anything I can do about it? Should I make or buy one of those sub stands? Should I be using the carpet spikes? (which I currently am doing).

Shawn,

Is it modes or nodes?

Both. :D

Modes are the natural resonant frequencies of the room, and nodes are the physical locations where the peaks and/or nulls occur.

I have to put my couch pretty much right in the half way point between the front and rear wall of the room. I've heard that this is a no-no do to the fact that low frequency waves pretty much produce a void at that spot

Yes, and relying on sub placement alone will probably not be able to overcome that. But moving even a foot or so forward or behind the center will help a lot.

--Ethan