How about both MDF and Baltic Birch My speakers North Creek Music Systems the Manifest has a cabinet built with Baltic Birch on the inside and MDF glued on the outside. The MDF is easy to veneer and you get the stiffness of the Birch inside. The two layers also give you a stiff cabinet always a good idea I also used Birch for ladder braces inside the cabinet for stiffness. George from North Creek uses a hard glue between the MDF and the Birch and a soft glue between two layers of MDF plus a layer of Birch for the front baffle 2 1/4 thick front with two layers of MDF , Baltic Birch + MDF 1 1/2 thick back and sides and 3/4 inch Baltic Birch for ladder braces. The hard glue is tight bond and his own soft glue hope this helps Marc
