How thick should the front baffle of speakers be?

The aluminum front baffles are interesting like kef ref and elac adante without having to go full aluminum. Ascend acoustics uses bamboo which is also very stiff.

and the improvement (without any other changes) was not trivial.

wheres the proof

wheres the proof

In extensive notebooks and old hard drives.

I just contacted my friend (he's now a major audio/video integrator in L.A.). He reminded me, that not only were the improvements audible, but they were measurable. 

You do understand that there are many tests that can be run on speakers, drivers, cabinets, crossovers, etc, that have direct correlations with sound quality, right?

Pulse tests and waterfall plots were noticeably better in deader, less resonant cabinets.

I don't even understand why this has to be explained? Build a cabinet with less resonance, that is better damped, and the entire speaker system has less resonance, and is better damped. 

The fact that YOU do not understand the types of things that make speakers sound better, is not my concern. The fact that you don't even own a system, and are commenting the findings (subjective and objective) is quite laughable.

3/4" plywood didnt work just fine. Resonance is a bad thing. Think of the surface area of a large speaker cabinet much if not all of which is vibrating.