[Accord Man]

try this:

take a glass of water and place it/attach it to different areas in your car.. (directly on sub box, ...or on a fixture coming off the the body..)

and observe the behavior of the water.. try as many correctly made boxes as you like.

dont forget that the box doesnt exist by itself, its in an environment (trunk), and a variety of factors/elements will influence it (react on it!).