What Do You Think . . . and How Does It Work?

not really. it rings like a bell.

Yes it can, when used for TT platers, and is forged, but there is a reason for that too. Galvanization issues.

With Metal housed planars. Forged, won't GROW Barnacles (as fast) as cast will. Cast alu without a treatment, can get flakey in less than 5 years..
Double in thickness in 15 years. Aviation shot peen, stress relieves and removes, pocket resonance, issues, also..

Most speakers that use Aluminum, use it for it's milling ability.
EX: GR Research LS9 (Beta) and a few other.
Infinity Infinitesimal  v.5 and 1.0 (cast)

CAST.. is actually the best , Highly porous, (to a point) dead silent.
Light, strong, easy to cast, easy to mill. A lot like a cast aluminum
engine block (neutralizing agent required)
Cast, Alu/Mag (no barnacil alloy) rims, dead silent. There is a reason they cast rims.. A lot quieter than a steel or spoke.

Columns.....

Regards..

Schedule 40/6" is 7mm thick. Schedule 80 is 11mm thick. I am rusty on my structural eng.

Cylinders echo and gain? ... no, they behave pretty much like any other "tube" whether it is square or rectangular, but more consistent and easier to deal with.

All materials "ring". If you have a material that does not ring (at all), then it is probably not stiff (or only stiff in one dimension). You can always add dampening. Open the hood of your car and knock on the likely aluminum block. Tell me if it "rings".

This design gets the benefits of a spherical design, but also adds a tapered tube at the back to eliminate all internal resonances.

Shape Variation
Cube +-5.0 db
Rectangle +-3.0 db
Cylinder +-2.0 db
Beveled Cube +-1.5 db
Beveled Rectangle +-1.5 db
Sphere +-0.5 db

Interesting, for a complete speaker system, round. smooth, tapered interiors, are a way to reduce pocket resonance. It can also be used to incorporate a resonance into an enclosure also.. That was my point, the GAIN factor, for BASS is a real issue for distortion in the bass region 250hz<

You have to use it or lose it, but you can't keep it.. 

When speaking of spectral decay effects on enclosure vs mechanical distortion (GAIN based) there is no comparison in how much one increases over the other. (The 20% bass distortion crowd, and don't even know it)
Interiors that are rough inside, not smooth are a much quieter enclosure.. The SQ is always better..

Remove the Highlands Scottish wool from behind the mids, let that blister your ears a bit..
or Remove the VERY coarse fiberglass from the bass enclosure...
BOOM....forever........

INSIDE, Smooth is bad.
OUTSIDE, Smooth is good, but just for the dust factor.
if it wasn't for that rough would be better.

Regards

I think it’s generally agreed in the industry that a box is the worst possible shape for a loudspeaker cabinet.

The main reasons why most are built this way seems to be consumer expectations of domestic acceptability and manufacturing convenience.

yep. We are being duped. Most audiophiles dont want to hear that though. Even ATC use box shapes and yet they are regarded as the finest speakers. It is all a hoax. 

The industry? Good grief!