Sound deadening in an apartment?

[BLindsay]

Hey all,

So I am going to be in my apartment for the next 3yrs at least so I was thinking of trying to sound deaden my home theater a bit more. I have a rather crazy idea but I wanted to see if folks had some easier tips to try.

I am on the ground floor (feels like there is concrete under me) and i have 1 person sharing 1 wall, then someone above me and someone across the hall. The folks above me are who I worry about mostly.

If there is nothing easier then my crazy idea is to build a room within a room, basically take my existing room and then build a box as big as i can within it, floor, ceiling walls etc, the advantage then would be in theory i could fill my new walls with some sort of sound deadening material (and also give me perfect light control)

Thoughts?