Speaker Stands Filled With Kitty Litter? TRUE???

No its a big lie, thats junk unless you have a cat.

jax2 has very good information.  Kitty litter has been used by some for decades, but it lacks the mass most seek.  Play sand is great and cheap.  Both dampen the ringing effect of sound waves striking metal stands.

I always used lead shot (with gloves on) and sand for my Sound Organization stands and it worked well.  Now only steel shot is available.

Of all the silly things I have heard. Stands are to elevate the speakers to the right height and angle them for time alignment. The speaker weights way more than the stand. Adding mass means nothing. But if you are going to use kitty liter I suggest you weight till it is loaded with urine. The smell will make it sound better.

Yes, the speakers can outweigh some stands, and that in itself can be a problem, making the whole assembly top heavy. Using sand or kitty litter to fill voids in a stand can add weight and help to damp any resonances the stand may have. I bought some cheap stands last year that used aluminum tubes on glass plates, with long bolts going down the middle of the tubes to hold everything together. The first few minutes of listening with my speakers on them I could hear a glaring tone. A tap on the aluminum tubes revealed that they were resonant at the tone I was hearing. Touching them I could feel  the vibration. Filling those tubes with kitty litter (unused) completely solved the problem!

Expanding foam.