I dont think "Deadening" ishte right term. If you are looking for more solid base, you try to lower the crossover point or get a higher quality crossover. because the surface area is so large on a subwoofer, high frequencies will cause the cone to resonate when mixed with lower frequencies, that vibration causes all the soudns to feel less clean.

idealy, a 12db/octave crossover set to 120hz would still produce 180hz frequencies at around half volume :o

 

i have dynomat, i didnt want to go lowes/home depot way even though its the same shit

 

so you'd rather spend 4 times as much money because....

 

Ive got a bunch of Dynamat if you want to buy some Ill make you a deal. I bought the bulk pack and just did my front doors...