Are exotic speaker cabinet materials overrated?

@faustuss Totally. It's why 99% of the time I stay off forums. I do enjoy helping new people after they get shot down by so called experts who make ridiculous proclamations that disparage their buying decisions.

@foggyus91 You're right.

Regarding concrete - concrete is a weak material, which is why it needs reinforcement if used for anything other than compression loads. It's also heavy, and expensive and time consuming to produce to a finish that would be acceptable for a domestic product. It's not very well damped either. So not a good choice for loudspeaker cabinets. 

@yoyoyaya I agree. You can bust it into pieces during delivery, installation or repositioning. But you can easily address dampening with fillers.

@pindac B&W uses the later. Those who don't use boosted EQ/tone control won't have issue. If you do, it sounds great up to a point where you need to upsize to a larger model.

@gdaddy1 interesting post re: wood layers and Glop. pray tell, what ratio of clear silicone to sand did you use? And how thick of a layer did you put on the inside?

@simao  I can't take all the credit. The idea comes from the Northcreek cook book.

To get the stuff to stick properly I coated the inside cabinet walls with contact cement first. Then pumped several tubes of silicon into a bucket and mixed in sand to what I felt was a good consistancy. Then, with gloves, spread by hand the entire interior. No need to smooth it. Just glop it in there. Let it be rather bumpy and irregular. Drys in a day and seals the cabinet as well as adding dampening to every square inch. Goes thick into the corners. Takes a little bit more effort but I believe it's superior to ANY stick on dampening pad.

Thickness is variable but I use about 1/4" thick in some places a little more. It's really up to you. Then goes in the normal foam or fiber fill stuffing.

The stuff stays soft and rubbery for decades and adds a nice amount of mass to the cabinet.