Putting weights on speakers?

A fun note...

The mass of concrete i added was bricks and slab of concrete... Around 80 pound more than 75 i think... The look is disguised with homemade resonators glued to the slabs... I will lie if this can be described as beautiful.... This look more like a " mad scientist lair" improvised apparatus.... My speakers are modified with stones and cables and little resonators etc.... My little children are baffled by the look tough.... :)

@mglik those Tetra speakers are so underrated you have no idea. You have a great taste.

@ebm 
and your post was helpful how?  

I have to say I'm surprised that helps at all.  Those cabinets being that heavy and the woofer being low to the ground (relatively) I would not think that was an issue.  I'm curious, when they play, can you feel vibration from the top of the woofer cabinet, or the top of the mid/tweeter frame, without the weight?