My scoops are made of 18mm 15 ply,but my mid boxes and tweeter boxes are made of MDF.
The cheapest way to paint MDF is to get a can of black spray paint.
Using Carpet or black Vinyl is expensive,not just the expensive felt carpet or black plastic vinyl,you also need a can of spray glue[the industrical strength spray glue].
And when you add this to metal ball corner protections and aluminium edging,it becomes pretty expensive[especially on a large cabinet].
The Touring Grade speakers[the ones which are flyable]
Use the finest water resistant Marine grade Baltic Birch 18mm 15 ply plywood,and use the finest primers,and special water-resistant paint.
The only wood which is crap is Partialboard or chipboard,
only alright for hifi speakers which are never moved.But having said that,if the hifi speaker driver units ever blow,and need replacement,chipboard is a absolute crap material,the screw holes flake apart and get bigger.
But partialboard or chipboard crumbles is in contant with water or even moisture,dense but any impact can damage it,also it looks ugly[all the pieces of wood chips and sawdust just glued together].And it can only hold screws once,otherwise the screw
holes get bigger or split.
So the only ok wood for pa/disco is: MDF,Plywood,Birch ply,Baltic ply,Marine baltic Bich Ply,pure oak wood,pure maple wood,pure manogany,pure pine,pure Beech.[All the pure solid woods are very expensive,but are worth it if you've got the money].