Originally Posted by tamiya
Where do you think is the best place to put it?
My layout would be like this. 19'x13'x8
Congratulations! That's a very good price for that subwoofer. To answer your first question about whether a single XTZ 3X12 will be enough, I think that depends even more on your own listening habits than it does on your room size. But, coming from your two JBL subs, this will be a big upgrade in output and tactile response. So, I think that the single sub may very well be enough.
With respect to your second question about the optimal location for your sub, I'm afraid that you will just have to experiment to determine what works best. Placing the subwoofer directly behind your listening position, in either a vertical or a horizontal alignment, could work very well. That would intensify the tactile bass sensations even more than the SPL (vertical especially so), and it would help to take the room out of the equation to some extent.
The potential downside to that placement could be that you might be able to localize the subwoofer more easily with it right behind you. Some people are a little more aware of that sort of thing than others, and it also depends somewhat on the crossovers you are using in your front soundstage. The higher your crossovers, the easier it would be to tell that bass sounds and sensations were coming from behind you rather than from the screen. But, I would absolutely give that location a try and see what you think.
If I were you, once the subwoofer is delivered, I would put some furniture sliders under it and move it around a bit. Once you have found the location that you like best, you can dial-it-in with Audyssey and really start to enjoy your new bass sounds and sensations. If you are like most of us, don't be too surprised if you eventually find yourself wanting a second one, just because.