What is your favorite material for loudspeakers?

I know about the WB designs but thank you for the post. I have used Carbon fiber I found it worse sounding in my designs than the Baltic plys etc. Its also costly hard to work with. So I leave it to companies like W.B. When Stradivarius are worse sounding than carbon fiber maybe I will revisit. Other composites are available for cabinet construction. I had better luck with those over CF. Hope your sale are going strong 2009 will be a hard time for retailers and audio manufacturers alike.

Johnk, the goals of cabinet construction for a string instrument and for a speaker are subtly different. . . a luthier uses the entire case of the instrument as a mechanically active amplifier. . . As such laminates like timber plies make for inferior student instruments because they lack the ability to propagate/amplify mechanical vibrations, not to talk about particle board which simply is anathema in cello/violin construction. The top of a cello is usually made from carved and finely graduated thin spruce. . . the bottom plate from almost equally thin maple or poplar. . . the two are mechanically coupled by an oaken post. . . . then of course there is the coupling to the strings through tailpiece, neck, and elastic maple bridge. The instrument is incredibly light and thin-walled, and vibrates and rings like it's going out of style. I haven't seen too many speakers that attempt to do the same. Hence, invoking the Cremonese masters is effective markcom, but. . . G.

Paino Black with Clear Coat paint.

I have to agree with Eldartford. No cabinet is the best cabinet. I love my stats.

Guidocorona
I suspect you could build a speaker enclosure to operate like a fine string instrument.
You could make one, or perhaps even a matching pair.
There is almost no possible way, for a reasonable amount of money, to mass produce such an instrument.

As for a practical (advisory) perfect enclosure, why not concrete? Heavy and inert, it would add nothing to the sound of the drivers. Add dampening to taste.

I'll stick to my panels.