Filling speaker Stands?

I use sand in my Solid-Tech columns, and it does the job quite nicely, although it is for my component rack, not speaker bases.

jrpnde OP
Well....I am the OP of this thread. There have been many suggestions as to how to fill stands with small openings, what that fill should be, and to what level of fullness should be. I have learned a lot based on the experiences of many.My take on all of the responses......the only way to find the best solution for me is to try different approaches. Of course, filling speaker stands isn’t as simple as trying other options such as just switching interconnect cables and the like.

>>>>>Eggs ackley! Which is why you cannot AB the various possible solutions, at least not very easily. It’s not that easy to AB one, if you ask me. How can you be sure? People generally pick the one that seems like a good idea and don’t look back. Furthermore, dry sand acts as much as a damper as adding mass. It’s the same idea as the sand-filled iso stands of yore from Bright Star. In addition, like my, ah hem, new iso stand, glass microbeads are much more efficient in their isolating action than sand ever thought of being. It’s along the lines of why woodpeckers are able to withstand tremendous negative g forces without sustaining massive head wounds.

Plus, as I already opined, isolating the speakers would be the preferred solution anyway.

My suggestion is 2 pot expandable PU foam with Pebbles or/both light weight filler diatomaceous earth, micro spears rock wool mix ... https://www.homedepot.com/p/12-oz-Fill-and-Seal-Expanding-Foam-Sealant-2-Pack-217272/203459971 and https://boatcraft.com.au/Shop/index.php?main_page=index&cPath=37
By this way you have total control over weight density
https://www.compositesworld.com/articles/microspheres-fillers-filled-with-possibilities 

You need to dampen vibrations and that means more than just adding mass. Sorbothane is the only material I know of which actually converts the mechanical energy to heat, thereby getting it out of the system quickly. I recommend 1/4 inch self stick  sorb , of the densest form, 70 duro. Use small pieces of sorb eg. No more than 1 inch across and cover with 4 layers of electrical tape, so as to make this a constrained damping set-up. You can stick these all over your speaker, I place them on the front, and thus hide them with the grill. The effects are amazing. The big companies are only slowly moving this way. Search constrained damping and you will find a lot of speakers doing variations of this. Grado and Sennheiser are using similar damping on their phones, although with Senn it appears to be only with their top.models.

I use uncooked rice.  Your situation of a small opening will require that you find rice with a small grain size.   Advantages:  availability; low cost; moderate weight; non-toxic; non-magnetic; minimal settling and compression.   Rice provides some mass, along with excellent vibration dampening.