Stereo & Electronics - sound deadening the hatch area...?

how many SQ FT do I need to do this? I'm going to buy Second Skin, the regular stuff for underneath the panels and the better shit under the carpet. Just need to know so I don't buy too much...guess it's better than not buying enough.

get a tape measure and measure the width, then add about 3 - 4 feet to that

then measure the length from front to back, pressing the tape along the area you want to cover then add a foot or two to that.

now multiply those two numbers together, and you have your square footage needed

thanks