I started a new speaker project last week, and I bought my MDF from a mill-work company instead of Home Depot. As I began to cut the parts out, I realized that this MDF was noticeably harder and felt a little heavier and more rigid than what I was used to. When I looked at my invoice copy it said "Double Refined MDF sheet". I searched the net to find that this board is denser than standard MDF and has more glue in it. It is used by mill-work companies for doors and other building products because it machines better.
My question is, for speaker building, is this stuff a good or bad thing? I like the solid rigid feeling of this material, but it also seems to make more noise when you hit it. It looks like it's somewhere between standard MDF and HDF (Masonite). Has anyone had any experience with this stuff?