How thick should the front baffle of speakers be?

So I shouldn't be able to put my martini shaker on top of the speaker and wait 10 minutes to sip?   :  ) 

plywood works. I question the use of large drivers 10" and above that can shake the wood. I also question the method of attaching drivers to the face of a cabinet. Where is the technology? I feel let down. 

bubble or regular gum?

Well I learn something everyday. 

Help me out here people. If the cabinet does not effectively deal with the waves off the back of the drive they will just bounce off the cabinet and the back of the drive. They bounce through that paper thin cone and ruin you precious sound. Hell you pay big bucks for your source and pre and amps and then the speakers reward you with crap. 

Wilson audio X...why is that any better then plywood? 

That is cheating..............

what the hell is "the near reflection free driver patent ( Vandersteen)"

Randy Bankert passed away a number of years ago. His front panel design was copied from the Zingali speakers that he had previously represented. Like many importers the manufactures always expect more sales and are never completely satisfied with the sales of the importer.

The thickness of the front panel should also be determined by how wide the front is. A large 16" panel will necessitate a stronger panel material. Narrow front panels not so much. Plywood is good, better then mdf. Alon  Wolfe went to plywood on his earlier versions of the Magic monitor. 

The price of 1/4" aluminum cost about $28 per square foot, price on buymetal.com

Many designers are using smaller woofers, they understand that the back waves often bounce back and right through the diaphragm. Not good. Those large woofers 10" and 12" suffer the worst. Not to mention the listener. 

I understood that Harbeth's design goal was to make speakers that do not store the energy radiating from the rear waves of the drivers ( not the same as vibrations from the movement of those drivers). To this end the design is a success. The design would not seem to be as successful with the large woofered 40's.  I would doubt they intended to make their cabinets sing. 

Thinking Nicki Minaj, Taylor Swift ??

I have listened to the Harbeths. They are not perfect and I think there are probably some frequencies that do tend to excite the cabinet. On the other side these heavy MDF cabinets store low bass energy and then release it slowly with a noticeable dead sound, the kind I do not care for.