Down firing sub tweeks

If you go with the base method, as I have, what I did was make the base a bit larger than the sub with slightly rounded edges at the top. After that, put a round spacer with a hole drilled in the middle between the sub and the base at the corners then get some large brass spikes with an internal thread in them. What you have to do is cut some threaded rod that has the same thread pitch as the spikes internal thread and the subs inserts and use that to tighten everything together. This way the sub and base is all one unit and about 15 pounds heavier. If you use granite, you'll have even more weight (mass) which will keep the sub more stable in the carpet.

I do this with my Rel Strata III down firing sub. I flip it over so it is up firing, put a nice thick piece of wood on top of the now upward sitting feet (I use a large 1" thick maple cutting board) and put something heavy on that. I also recommend getting it out of the corner. You will have to turn it up a bit louder but with both of these changes you will now have something that is absolutely faster sounding with better overall pitch definition.

PTM
this is what Vandersteen does out of the gate
as well as High Pass
Cheers JohnnyR

PTM, this is interesting as I'm always looking to experiment. Is the sub simply sitting on the floor or did you fashion some type of feet?

Just sitting on the carpet in my room, so it doesn't scratch.