I was going to staple the insulation to the frame from the rear using the facing.
I also had no real intention of bass control with these panels, but was curious what the properties might be. Proper bass control will come along later.
So the layers from front to back would be burlap, batting, non-faced side of insulation, kraft paper, batting, and finally burlap on the opposite side.
I am still trying to understand the concepts of sound absorption, but how does facing behind the insulation reflect sound? Does it come into the insulation, hit the paper, and bounce back out?