Yeah, I did have some warping. I used standard butt joints, and had to twist it a bit to get it lined up. It sits better on carpet, than hard floor. I've used ply for baffles. I see no reason to use MDF unless it's the only thing available. MDF and particle board can only take so much cutting and drilling before it crumbles. And unless it's covered well with paint or tolex, it does NOT like any moisture.