I love ADTR! I helped my friend get this sound almost perfectly! We cut up a bed pillow, and took another one.
1) Lay the intact pillow down in the bass to where about 3 inches is sticking up on the batter head.
2) Take all the material in the pillow (Cotton, feathers, etc...) and pile it up on top of the pillow. Tape the intact pillow down and put one or two pieces of tape on the pillow material.
3) Tune the batter tighter than usual, same with resonant.
4) Go buy a kickpad (Falam Slam, Kick Pad, etc...) and stick it on there.
5) Use the hard plastic side of your beater on this.
6) (OPTIONAL) If you would like to install a port (or already have one) put the cotton under the pillow and secure with some tape so that it is pushing up against the batter head with about 3 inches sticking up.
Don't Forget! Lightweight stuff will move in your bass, such as the material in a pillow, so tape it down a bit.
I hope I helped, and I know that it worked for my friend! His bass is killer!!!!!