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

@dave_b - speakers aren't the same.  Musical instruments are designed to resonate.  That's how they get their distinctive sounds.  Speakers, on the other hand, are designed not to resonate.  The less they resonate, the less of their own sound they have and the better they can reproduce the distinctive sounds of musical instruments.  

I’ve had the inert kind....sorry, but they do not sound organic and alive like real music.

Dave, have you heard all of them? I highly doubt it. Not sure what price ranges you are talking about, but I'd love to hear your conversation with Richard Vandersteen or Alon Wolf about this, lol.  Sorry, but you can't make that statement unless you have heard all of them.  I promise you my Vandy Quatrro's are plenty organic adn alive like real music in my room.  Plenty of speakers I've heard are outstanding and sound like live music and they are made of all different types of materials.

Totem are also nice speakers and I've enjoyed most of them at a local dealer as well as a dealer in NYC.  There is no best.  It's all design and implementation.

Ctsooner, I wasn’t implying any particular speaker was “the best” silly.  I am saying that most of the speakers that I have owned tended to deliver a more natural sound when made of wood.  The worst were the Wilson’s.  Magico’s were overly deadened to my ears.  Anyway, just saying I hear a dramatically improved sound with a well done wood speaker.  Harbeth uses this approach as well I believe.  

@georgehifi   your post about the surfboard hits the nail on the head. It's easy to think that stiffer/stronger/more solid must be better, yet all the strength in the world is no good if the cabinet becomes a soundboard at a critical frequency, especially in the midrange.

It's possible for loudspeaker cabinet materials to become almost transparent to the sounds coming from within the cabinet at certain frequencies again.

I think experiments have demonstrated that MDF untreated is more likely to act in this fashion.

And then there's the issue of a cabinet being too rigid and causing back pressure through the driver materials themselves.

Hugely complicated business is cabinet construction. Open Baffle gets around most of them but has its own issues.