Sony's masterpiece of engineering of the 1980s - available in Japan only.
Along the (much) bigger SS-G777ES, and despite a very attractive price, the G333ES seemingly sold very little. Why oh why? Because "Sony" is written on them and as we all know, that can't be good.

However, gather around and listen:
the SS-G333ES' bass and mid drivers useSony's own High Stiffness Polyolefin which is stiffer and lighter than almost everything. Also it is resistant to heat and water. And the tweeter is made of 99,9% pure crystals of Alumina - way lighter and faster than titanium. And if you click the "more" button below, you'll find the rest of the engineering details taken from Sony's own DIGIC corporate magazine.

But this I'll emphasize here : since 100% non-resonant enclosures are science-fiction only, why not tune the residual resonances to something useful? Well, the enclosure and baffle of the G333ES are tuned to resonate at 365Hz (rear), 457Hz (sides) and 550Hz (top). And those frequencies are the equivalent of the following musical notes: DO, FA and LA (C, F and A for you anglo-saxon people).

How's that for engineering extra-ordinaire ?