I dont know the stands, but if they are metal, you want to fill them to damp the ringing. I think they're probably heavy enough. My dealer recommended, and I use, Jonny Cat kitty litter, unscented. Cheap, fill them up all the way because it doesnt cost or weigh much, and it works great. If you really want them to be heavier than they are, mix shot or sand with the kitty litter and fill them up all the way.
That said, some people have reported that their speakers sound better with the stands only partially filled. I dont why that would be, but you could just experiment.
That said, some people have reported that their speakers sound better with the stands only partially filled. I dont why that would be, but you could just experiment.