Is the bassport clogged? There will be no bass if the bassport is completely clogged. And I believe there are two ports, one inside the cup on the white foam/fabric like material where you'll find a tiny hole somewhere, and one on the magnesium cup itself, on the outside.
Sounds very reasonable and good what you are suggesting. I hope I can identify the inner bassport. The big hole on the outside was good as far as I remember. I hope I dont have to buy them again but I would. Will check on sunday when home again.