Quote Originally Posted by Cal Weldon View Post
Might that be a little too absorbant a material? ie: over damped, perhaps affecting the response?
Depends on how well the horn surfaces are sealed. The structure itself should be so far below a tweeter's operating range that it will be akin to a large, low tuned, tar damped, multi-cell.

So the 'name of the game' is to find a material that's either super slick or at least doesn't swell up to cause a micro rough fibrous horn surface when coated with 'whatever' to seal it. FWIW, the thin plastic used to stamp out hotel/motel 'maid service' doorknob hangers is what I've used for tweeter WG experiments, then contact cemented sheet cardboard on the outside to create a well damped, yet rigid enough, constrained layer construction.

Unfortunately, I don't know what type plastic it is or where to get it these days, I special ordered it from a long gone hobby shop as sheet stock of varying thickness for making slot car front/rear air dams.

GM