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

I would say that because MDF is heavier then Plywood it is going to have a lower resonance point, meaning the MDF will store vibrations longer, much like a heat sink, and release it slowly causing a smearing of the imaging. Then by bracing in an effort to eliminate resonance mass is added, which again lowered the resonance point. Imaging ringing the bell in the tower of London as compared to the bell on a bicycle. Lots of energy off the back of the driver is headed to the cabinet.

Another illogical argument based on lack of knowelege of material resonance. Thick and highly braced MDF cabinets have a higher resonance point than thin walled designs like a Harbeth - usually  in the >400Hz range. This is what happens with very stiff enclosures. The bell analogy falls apart because each would have to be struck with the same size clapper. You'd be striking the London bell with a bicycle clapper. You're basically referring to the Gandy argument of how materials store energy, problem is, he too has a misunderstanding of materials science. Put a stethoscope on any of his plinths and you'll hear rumble galore compared to a high mass design.

helomech

Tell that to Harbeth....

Slightly off topic - but Martin Logan CLX have no cabinets and they certainly sound fine -  i think HDF makes the most sense if you are looking for consistency - eapecially when cut and prepared with CNC machinery - i dont see how they can match the left and right cabinet properties if you are using plywood or natural wood regardless of the wood type or mumber of layers - it is impossible to build two cabinets with identical sound absorbtion / reflection properties with anything other than MDF or HDF.  PMC speakers - widely used in most recording studios use nothing but HDF or MDF - although they baffle the cabinets with a proprietary insulation material -  but i would think natural wood would be the worste choice for cabinets because of the tendency to change properties with the climate and humidity - as well as the impossible task of trying to have two cabinets with exactly the same charactiristics 

@soundsrealaudio

Harbeth seeks to control resonance by lowering its frequency to levels below the midband where our hearing is less sensitive. The difference is they’re not trying to reduce the amplitude as many manufacturers attempt (yet fail to do). Your argument was that plywood is a superior material to MDF, well won’t you be surprised to learn that Harbeth uses thin MDF panels combined with bitumen sheets.

You assumed that heavier MDF cabinets will have a lower resonance frequency. The reality is that it’s stiffer and will have a higher resonant frequency - toward the midband and often above 400Hz - not the best approach IMO as this is closer to a "ringing" as you might find in metal cabinets.

I happen to prefer the BBC/Harbeth/Spendor/Stirling Broadcast/Graham approach - whether it’s MDF or birch plywood, they all make excellent speakers. However, all alse being equal, for a given mass, MDF is less prone to resonance than solid wood and plywood.

Twisted login helomech....where do you get this Schiit.

Another illogical argument based on lack of knowelege of material resonance. Thick and highly braced MDF cabinets have a higher resonance point than thin walled designs like a Harbeth - usually in the >400Hz range.