Putting weights on speakers?

@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?

I use the same tweeters by the way, and those are phenomenal. :)  It's interesting the woofer is crossed as high as it is.  1 kHz... Hmmmmmmm...

mahgister, what happen's in the audio room stay's in the audio room. I imagine this is the look your wife give's when you explain your tweeks. 🙄

basically you added mass and therefore reduced the natural frequency of the enclosures. 
is there a limit to heading in this direction where the sound becomes something we do not car for?  
example- Magico aluminum enclosure speakers and subwoofers.  
somehow the bass response of these speakers was foreign and disorganized.  the midrange and treble were phenomenal but the bass was horrible.  i suspect that the enclosure was too rigid and actually causing the drivers to resonate.  just a guess.

if we made enclosures from concrete, would the same thing happen?  

i believe we are used to a certain amount of cabinet resonance and like what it does for the sound.