Hi os2009,
I just wanted to put in my 2 cents about the JBL Venue Series SUB12 12-Inch 500-Watt Subwoofer you are looking at. I picked one up a little over a month ago and was very unimpressed. Now granted I did not go through any real testing for placement or anything like that, but I do not think that in this case it would have mattered too much. I did setup the bass management on my receiver.
I was attracted by the price as it was my first subwoofer purchase and I can now definately say you get what you pay for.
I watched a movie with it, Matrix, and at first was impressed as it was my first experience with a sub. I then went on holidays and watched another movie with it when I came back, Blade II, and was left wanting. I know you cannot judge a sub by watching two movies with it, but I do not think I would really be happy with this sub, regardless of the movie.
The worst part is that I am now a week past my return date and cannot take it back, tried and was sent packing. E-Bay here I come
I would look at an SVS or HSU option for a subwoofer, I know I am
Good Luck
Michael