I just got the Z-5500 Speaker system and i wold like to know ware is the best place to put the sub?

Answer 1

It all depends on the size and shape of your room.
But for subwoofers, anywhere you put them, they are fine.
Their sound is lower so they can travel farther, so if you put it on the floor, on top of a table, or anywhere, you can still hear it.

Answer 2

read:

http://www.polkaudio.com/education/article.php?id=15

specifically the bottom of the page