I've tried lead and sand and have settled on concrete powder. It's extremely dense and dead for sound. Non toxic and plentiful/cheap.
Sand and shot?
This question is really for what most bookshelf speakers sit on--the stand. I'm planning on filling a set of stands(24") but just have the sand presently. Do I really need lead shot as well or will the sand be enough. Most reviews I read on speakers mention stands with both. Any help would be most appreciated.