DCAudioDIY.com

If you are looking for MDF for speaker building look at the Woodworkers Club in Rockville -

https://woodworkersclub.com/wood/plywood/

In addition to regular MDF they have TruPan (a form of MDF) in 1 and 1 1/2 inch thicknesses. Also check out the other woods available.

Also I forget to mention they have a panel saw and will cut the MDF to smaller (lighter) sizes. I got a 4'x8' sheet of 1 inch TruPan and had them cut it into 4 2'x4' pieces.

With TruPan being lighter, I winder how it does as far as damping the vibrations?

They say it is 20% lighter.