Sub Connections

[Dale M]

Hi
Im wondering about my sub connection. I am coming out of the reciever from the sub-out plug and going into the (Sub In) plug on the sub, there is also a plug in that says,Direct In,
right beside it, both are under the low level heading, and wondering what this is used for??
Also is there any advantage to coming straight from the receiver into the Sub first with the left and right speaker wires and then to the speakers? the receiver is an HK-225 and I dont think you can set the crossover points for the sub thro the receiver,I have put a couple pictures of the rear of the sub on here so you can see what Im talking about,,
And one last question,, as you can see the sub is kindof wedged in between 2 couchs it works well there as you can't really tell where the sound is coming from but you can feel it, , but I am wondering if Anyone has any expierence with Butt Kickers?? I like to feel the ground shake in some movies.
Thank-You
Dale M