I like your simple cup solutions above bmf.
That's my conclusion after adding more than 1 layer of Paxmate and more than medium mass loading the baffles.
Doesn't adding anything over the back of the white driver felt further dampen the sound?
Im not sure what you meant by that last part? the 2mm white creatology floppy felt im using doesnt touch the driver... it sits in the back of the cup. Im using this felt since it looks and feels like a consistant density teased cotton ball. here is a picture of the inside of my cups without the felt square... the picture is of a previous mod that i didnt like so ignore the square of facial sponge material. that sponge material made it sound stuffy. and the highs were gone. yes, i know thats alot of clay on the baffle. I have stock felt front and back of driver with no reflex dot.