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

Doesn't Harbeth use solid wood for its cabinets?

^ They use relatively thin MDF panels, veneered on both sides. I believe a couple of their models use a combination of ply and MDF.

Here is what I would say about that. How many CONCERT level instruments are made out of plywood or MDF?

Answer = 0

While a speaker is not an instrument in the sense that you can play it, it shares ALL of the concepts of a device, usually some type of chamber in which sound is projected for the audience to hear and enjoy.  

It would seem to me that Wood would be the obvious choice.

If the goal is to hear the resonating wood (as is the case with string instruments), then yes, solid woods are certainly the best choice. If it were the most inert and neutral material choice, we wouldn't have such large variations in the design of string instruments. Any experienced guitarist can tell you that sitka spruce and maple sounds brighter than mahogany. Hmmm...ever wonder why the call them "tonewoods?"

Further, as mentioned in the white paper linked above, solid woods are not isotropic. They also have too many inconsistencies in terms of density and grain patterns - even with cuts sourced from the same tree. This is why no two string instruments - even from the same luthier - will sound exactly the same. These issues could create problems for pair matching of speakers.

@invcitus005  

You clearly do not know much about the live concert instruments.  I can not think of a string instrument that isn't made out of wood which is UNIVERSALLY individually selected.

For example, PRS guitars have 2 distinct level (this is very common among concert level instruments) General line, of which some are made in Korea and the remainder are made in the USA.  Then there is their private stock line where the woods are individually selected for their tonality SPECIFICALLY.   

That last word explains my VERY sound logic Invictus.  Woods have tonality properties that NOTHING else will reproduce. SOME have exceptional resonance qualities and these are selected by luthiers.  You know its why a Martin D45 that was made in 1941 is for sale for $350,000.00.

Its also why a 1957-1965 Les Paul sell routinely for $100,000-325,000.  New these guitars would have sold for $300-500.  I purchased my 1974 Les Paul for $350.00  Today, its worth 10 times that much.  As it ages it will continue to rise in value.

Anything that is resonating sound, AKA music, the type of wood matters.  The idea that wood vs MDF/Plywood doesnt matter is utterly absurd.  Sure you are going to pay through the nose for wood but it is a FAR superior choice.   

Just a guess, but Im betting these arent made of MDF or Plywood.

 https://www.audiogon.com/listings/lis8jgf6-cessaro-liszt-horn-speakers-full-range#&gid=1&pid...

@bukirob I clearly know all about the musical instruments. However, I have a hard time comprehending your backwards logic. It’s clear you don’t have the slightest idea on how good speakers are and should be built.