Tech Ingredients is but one resource that has percussion measured Baltic Birch and compared to MDF. The differences are small but real. Intuitively, I'm inclined to agree with Early B that many, if not most, folks would be hard pressed to hear a difference, all else being equal. If someone were willing to orchestrate such a test or provide me with the means, I could supply test mule cabinets. I have yet to see such comparisons with Bamboo, but would like to. Planet 10, where is it you get MDF for free? This past year has been truly a booger for consistent supply.
Some things to consider.
1.Hi density MDF (like Ranger Board Platinum or Medex), is certainly easier to hold down (vacuum) and machines more crisply on CNC router. As a result of this consistency in flatness and density I can achieve a higher average yield of parts per sheet. No small thing in a manufacturing environment.
2. All MDF is not equal. Nor is plywood. There's no magic bullet here. Better quality is more expensive as a rule, but spending more guarantees nothing in the speaker realm.
3. Baltic Birch and a few others like Appleply are unique among plywood because their core plys are hardwood. Most North American hardwood plywood uses softwood for core plys. There's also several hybrids that use MDF for the outer ply that veneer is attached to. It is indeed available in 4x8', but not common outside of industry.
4. Baltic Birch is not graded like North American plywood because it's not manufactured here. A2 would be typical grade stamp for hardwood veneered ply. The A face being best grade available, and the back (2) grade being somewhat less, but not bad.
5. Baltic Birch is commonly available in two grades. B/BB and BB/BB. There is not huge distinction between face and back. The outer plys are typically one piece, rotary cut and plugged defects are possible in either. The primary difference between the two is the core plys are sorted for color. This makes the edge look more like the face on the B/BB, and raises the cost significantly.
5. Baltic Birch, for the most part, is considered utility plywood. Yes, it's has hardwood faces, but as pointed out, it's not the "prettiest pony". Staining and dying are difficult at best.
MDF, despite people's dislike, is a viable product for speaker building. It's reasonably priced, consistent in flatness and density, and decently damped. I don't have love for the stuff, but's it's suitable for the task and manufacturing in general. I suspect that's why it's used so much in the commercial speaker building world. It just checks more boxes than alternatives.
