Question for sub woofer users

I concur with the above. After a set up period, you should have things dialed in. As far as a sub for the quads, I would recommend a Vandersteen sub.

I have resisted having a sub until last year.  Consequently, i was never happy with bookshelves (limited bass output), and i have tried several floorstanders that were never perfect. So i decided to give a shot with the svs sb1000, and setup was easy.
  It is connected to the preamp output of my integrated,  with the filter on the sub set to 50hz, frequency at which my speakers start to cut off.  The output level on the sub was set using my ears and white noises at various frequencies to achieve even coverage down to 30 hz, maybe a little below. 
I am quite happy with the result, movies are more lifelike, and i now have been back to bookshelves as the bass output is almost what the vandy 2ce were putting out. Swapping bookshelves is much easier than floorstanders.
I would need a second sub for my setup to be perfect, for me at least.  But i think my wife would punish me.
I have no other experience with subs, but it made sense to me that a sealed sub would be much easier to setup.  That is one reason why I picked the svs.

Read in a book that a good place to set a subwoofer is as close to the listening position as possible . Have been using that method for a few years . Works well . You would think you would sense the sub being so close , but the bass seems like it is emulating from between the speakers . Pretty cool . 

Thank you all for sharing your experiences and advice.  I'm going to start watching the listings and if something good comes up at a price I can afford I'm gonna give it a shot.

Several of you felt that two subs were waaaaay better than one.  Others, not so much.  The phase issue with one sub was mentioned and that would seem to be pretty important. 

Should I be looking at two subs instead of one?  The available room is not a problem unless, as lustformusic felt, that the subs were best positioned inside the speakers.  This may be a problem for my wife as there is a television that would probably be in the way.

Thanks again, you guys are great!

Bob

Forgot to ask a question;

I've got a Prima Luna integrated that has one "mono out." 

Is is possible to hook up two subs with only one out?

Thank you again.

Bob