if you were to deaden the hatch, is it really necessary to do the whole hatch to get full sound benefits (im not talking about reducing road noise), but if you had a subwoofer, would doing the whole hatch add much benefit as opposed to certain parts of it, and if only parts of the it, which parts would be the best places to lay down the sound deadener???

 

Spare tire well, wheel wells, and any other thin metal close to the outside world.

 

If you mean just the hatch itself, the more mass the better*, especially if it's high tech constrained-layer damping material being added.



*until the struts can't hold the hatch up any longer

 

using polyfill(pillow stuffing) in the rear quarter panels helps a ton also. grab one 15 lb. box from wallyworld will easily do to fenders.



i soundproofed my entire interior plus i filled the rear vents behind the wheelwells with spray foam.



sprat foam was taken out later on and i patched sheet metal over it.