Which material sounds better for speakers construction? Wood, Ply or MDF?

invictus005 is completely on point in his post!

And, since I work for Paradigm, I’ll toot our own horn on this subject...

In regards to the Paradigm Personas:

The drivers are the only things we want to "sing" so we developed an enclosure that is completely inert. The enclosure is the launch pad for the drivers, holding them rigidly in place and dissipating the rear sound wave that they create, so that only the sound created by the drivers enters the listening room. To do this we build the enclosure out of seven sheets of wood composite material - High Density Fiberboard (HDF) with a Viscoelastic adhesive in between each sheet in a "Constrained Layer" configuration.

While the composite materials are being formed into the characteristic curved shape in a 5-ton press, a combination of heat and high frequency RF radiation is applied to begin curing and setting the adhesives. The curing process takes from 2 to 5 days. After that, the enclosure is carved to the proper
dimensions with a 5-axis CNC router. Lastly the FEA optimized marine plywood bracing is inserted and the end caps are installed.

From there, it goes to the paint shop to get its luxurious finish applied. This process involves 10 coats of primer and paint, with both hand finishing and new robot finishing methods utilized in between coats. From start to "finish", the cabinets take over 4 weeks to complete.

This is the ideal way to build a cabinet for an ultra-high performance loudspeaker. The only reason it’s not more widely used is the massive investment in tooling that is required. The result is a cabinet whose beautiful curves and fit and finish enhance its overall appeal and performance - much like a world class sports car.

So in short, having the resources we have at our 225,000 sq ft facility near Toronto, we can use anything we want to build cabinets, and this was only to explain how we build our best products. All the technology in drivers and crossovers don’t matter if you put them in a poor environment.

There is more I can share on our Personas, but I only wanted to explain what the subject pertained to.

Thanks to everyone who took, or takes, the time to read this, I appreciate it.

I hope it is OK if I ask this here, as search engine brought me here.  Do all these factors also apply to the foundation mounts for high end car audio woofers?  Specifically, which is a better material for mounting 6.5" Focal Utopia woofers, mdf, wood, or aluminum?  Or does it simply not matter for a cylinder shape in the same way it does for a closed cabinet?  If I use CDT aluminum car speaker mounts, cnc'd specifically for my car, anything wrong with lining the inside of the cylinder with 1/8" closed cell foam?  thank you in advance.

All companies believe they have the best approach.  Implementation still matters the most.  You can have the most inert cabinet, but if your speaker is bright and fatiguing or can't image or has terrible bass, it won't matter. 

Ton's of approaches to building a cabinet and lot's of great speaker choices.  We are lucky to be in a great age of audio where we have so many options.  

Out of curiosity, as I am planning to build my first speaker soon, would MDF with a glued on Formica (smooth countertop laminate material) on the “inside” of the box work, or would the extremely hard Non-porous Formica cause too harsh of a sound?  I know I’d have to have some sort of sound batting or something inside also.

Good quality MDF doesn't need finishing on both sides. You can leave the inside surface bare.