JL> some guy was at my school today doing a project on 
 JL> lined with concrete and he 
Years ago, the old Warfdale speakers used the "box inside a box" concept.  
They built their high end speakers with an inside box, which the drivers were 
mounted in, and an outside box, which looked very nice.  Inbetween the two 
boxes was SAND!  The idea was to create a completely inert enclosure to 
reduce the coloration of the sound.  
I've read in other conferences (internet) of similar experiments (to concrete 
usage).  It appears the agent used to bond the wood to the concrete makes the 
difference between success and failure.  Using an adhesive, such as silicone, 
is a bad idea.  The silicone allows the wood enclosure to vibrate, isolating 
it from the inert concrete.  Using an epoxy adhesive results in a much 
tighter bond.  In any case, the discussion showed this was generally 
overkill, and using various internal struts and layered high density particle 
board tends to result in a similar sound.
  Dave
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