Speaker cabinet materials.

Bamboo laminate is used by Escalante and Ascend Acoustics. Ascend has a CSD graph of the bamboo cabinet to show how little resonance there is in the v-lam bamboo. Go to the last graph on Ascend Acoustics Sierra graph page to check it out.

wilson benesch... steel skeleton wrapped in carbon fiber.

I love my granite cabinet made Ridge Street Audio "Sason" loudspeakers. Every time I compare them to other speakers that use other types of cabinet materials, I swear the bass from the granite speaker sounds much more delineated and has quite a bit more harmonic character all throughout the bass regions. The imaging solidity and clarity in the treble are also beyond reproach. Is this truly a function of the granite material? I don't know for sure, but I can say without question that these speakers do many things that no other speaker that I've owned can do!..... (13 different speakers at last count)

Vandersteen Audio model Five As and Quatros offer a unique constrained layer Damping system in a sophisticated multi enclosure.

When John Atkinson of Stereophile magazine measured their cabinets he said they measured insanely dead.
All of this is important yet the most dead cabinet in the world set up in a room with heavy bass nodes can defeat the purpose
The Room compensation feature of a properly tuned Five a and Quatro further allows the efforts of all this work to be appreaciated. ((take a listen...
John

I just picked up a nice pair of concrete speakers, the Rauna Frejas. These are a very heavy smallish 2 way with about a 5' woofer and a soft dome tweeter. So Far I relly like these. Other vintage speakers in my collection include Large Advents, Microaccoustic frm2 & 2a, DQ 10 and 20, Vandy 2ce, Polk Sda, and belle klipsch. I drive these with assorted vintage ss and tube electronics.