This should have been detailed in the mod. I feel this is important. (Please consider it Mrspeakers)
~~~~~~~Lastly, the craetology stiff felt~~~~~~~~ (or whatever stiff felt you're using. Before application to the driver, observe the stiff felt carefully. You will observe one side is 'smoother' (and slightly more porous) than the other. This side is 'softer' to the touch than the opposite side. Make sure this side is is faced down towards the driver. and the harder side (slightly more 'plasticky' feel than the other) is the side that is face up (is facing you) upon application.
This is critical and I notice it did not make it into the mods.