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

Use 5/8 inch mdf, layer of non hardening glue, 3/8 hdf, layer of non hardening glue, and 5/8 plywood to support them. Near perfect without the cost. Perhaps put the hdf 1st. Toss up. Enjoy. You have 98-99% at reasonable cost. If you’re obsessive switch the 5/8 mdf for 5/8 + of granite for your baffle. Your there with the big boys at minimal cost. 

Just make all walls 2.5 inches thick. Brace front to back with old (dry and shrunk) hardwood. And use granite glued onto the front. Voila! Success!!!

@ebm. So true that high performers,or expensive items, are often maligned  by those who can’t afford them.  It’s funny really :)  many Timex wearers think Rolex is a total waste of money since it doesn’t keep time any better ;)  And for those types; often artwork is simply ink on paper - another waste of money ....