Auralex SubDude

Mateored, rather than lead shot, you might try a bag of microbearing steel from eBay or a foundry supply company. I use this inside the enclosure and in an ultrasuede bag placed on top of my modified Merlin VSMs. The Merlin is particularly active with vibration across the top of its cabinet. Microbearing steel is more reactive than lead shot in absorbing vibration and is of course non-toxic.

06-08-12: Mateored
Interesting. I need to do more listening. I think I might experiment by putting some weight on top of the sub to damp the movement a little. I've heard people putting bags of lead shot on top of subs.

Several years ago I got a fairly inexpensive 1x10 powered sub. I felt it could play cleaner. I had a slab of granite I had gotten from a Tandy store (just $20) for leatherworking. I placed the slab on the subwoofer (with a layer of shock-absorbing shelf liner in between) and voila! It made the bass much cleaner and more linear-sounding.

I agree with David and Johnny. IME, adding weight to the top of your sub results in a noticeable improvement in pitch definition and transient response in the bass.

I have my JL Audio sub sandwiched between weights and a platform.

--On top... 40 pounds of weights concealed inside a Bright Star Big Rock platform. Under it...

--A large piece of industrial felt. Under it...

--The sub itself. Under it...

--2" Black Diamond Racing carbon fiber "pucks." Under them...

--3" maple platform. Under it...

--The floor.

The final result looks like this.

I did that in increments, and I heard improvements with each step, including when I placed carbon fiber pucks between the sub and the maple platform, bypassing the sub's soft feet.

I recommend trying something similar, if you're inclined.

Bryon