Product to fill up speaker/audio stands and racks

I used playlot sand from Home Depot, loaded using a funnel. Theoretically, this could be messier than shot or rocks, but I like the better packing density.

I'm in the playsand camp too. It's cleaned and dried. Go to an auto parts place and get a good funnel with a long spout that you can manipulate around a bit. I measured out the sand in a separate container then used a plastic cup to move the sand from the bucket to the funnel. It took about 15-20 minutes per speaker but I hardly spilled a grain. I also like the resonant damping qualities.

I prefer not to use sand. Unless you get a well dried silica sand, the moisture in it can aid in rotting your metal stands from the inside out.

Go to a reloading shop and get some lead shot. Cheap enough, extremely dead and doesn't make a mess. Just don't eat it.