QD-13 DIY Quadratic Diffuser Plans - What wood?-Acoustics Forum-Acoustic Fields Forum

Hi Dennis!
I’ve purchased the DIY Sound Diffuser QD-13 | DIY Quadratic Diffuser Plans – and the instructions state to utilize MDF, Alder and Basswood.
However, the instructions do not say what part of the diffuser requires what type of wood.

From the pictures I’m trying to conclude that the walls of the unit (back, sides, top, bottom) are MDF, and probably the other parts (inner panels) are Alder or Basswood?
Could you let me know which part is supposed to be what type of wood?

Thanks!

Efraim