Why are there so many wooden speakers?

Don't we have a few speaker manufacturers that hang out here?

This is all at the theoretical level - it would be nice to take it to the experimental level. Get a manufacturer to make a pair of speakers (perhaps their mid  priced models) in two or three of the materials discussed here. 

Then do a blind listening session with everything identical except the cabinet materials. If no one can tell the difference, discussion over.  If they can, it would be interesting to hear what those differences might be.

My Harbeth 40.2 Monitors are real wood veneer cabinets. I love these speakers. What's my problem? Should I be unhappy?

@wspohn I have done this. This was literally part of the process I used when starting up my company to identify what materials I wanted to use in cabinets and if cabinet material makes and difference at all.

I have created the same speaker with MDF, bamboo, fiberglass and carbon fiber and a 3D printed version using carbon fiber reinforced ABS. The only deviation was the internal brace was thicker in the bamboo (.5") and MDF (.75") compared to the other materials. Used the same drivers, crossovers, ports, wire, binding posts, even weighed polyfill down to the fraction of an ounce.

There is an obvious difference in sound as stiffness of the cabinet increases and in the case of fiberglass and CF materials I use, damping improves.

What happens is the tweeter is literally louder in the stiffer materials. SPL is measurably different and the amount of detail you hear decreases as the quality of the cabinet material drops. You can offset this by adjusting resistor and capacitor values in the crossover but this tends to make the speaker slightly brighter in a bad way.

In order of cost, MDF, Bamboo, Fiberglass with nomex honeycomb core, 3D Printed CF reinforced ABS and Carbon fiber with a nomex core. I used an ETON Ceramic Magnesium Tweeter and a Symphony II driver and had the crossover design completed by a third party.  These materials were chosen because cost to prototype wasn't insane. Aluminum costs to prototype are insane.  As are titanium and casting a thermoplastic like phenolic resin.  

3D printed was by far the worst. My wife said it sounded like I taped a sock over the tweeter the sound was so flat. This was so bad, I never took measurements and have abandoned the idea of a 3D printed speaker for the near term.  

In CF, the speaker is forward above the crossover point. The speaker is/was extremely detailed and a little bright. In fiberglass, it was neutral to laid back. A relative lack of detail though it didn’t sound bad. In this case, the only difference is the # of layers and type of composite. The difference in sound is not small. Anyone can hear this difference unless you are suffering from some kind of hearing damage. I don’t mean the difference in sound between two cables, I mean the difference in sound profile between Klipsch and Sonus Faber.

Even in the final products, although the drivers and crossover in my Nightshade and Blackthorn products are physically interchangeable (same size and mounting points), they sound radically different and I could never swap Nightshade drivers in Blackthorn cabinet without first making a crossover change and vice versa.

Bamboo outperformed MDF unsurprisingly (it is stronger and denser) and both underperformed relative to fiberglass. The major difference (and what made the test somewhat unfair) is that the sandwich panels I use are self damping. They are literally designed to deaden sound in transportation applications like helicopters and planes. Bamboo and MDF both lack these properties and need some additional help. Simply using the right insulation inside the cabinet can radically improve performance of MDF and Bamboo. When additional measures are taken; mounting mid-range and tweeter in another material like aluminum, using a different material for the baffle altogether, using fiberglass, rock-wool, etc..., using higher mass drivers, and I am sure countless other approaches can radically improve performance of wood and MDF.

But again, when you are holding everything else constant, the differences between these five materials are not small.  Anyone could tell the difference.

It is highly debatable as to whether the incremental cost for any of these advanced materials is worth it.  The paint-job on my Blackthorn or Nightshade speakers costs me more than a pair of Kef LS50s so this becomes an argument about diminishing returns and value which is personal.  

Acoustical instruments are never had from MDF.  Why?  It kills sound. You want to have an inert cabinet. With some bracing where needed, MDF makes for an excellent speaker cabinet.  Put wood veneers on it for looks.  Or, use sealing techniques and paint to a high gloss finish.  Nothing wrong with MDF.