I've got those foam things on all my speakers (same sizes as yours). I put them in to protect the speakers inside the door from water and dirt. I only cut a slit in them to get the wire through. There probably is less bass, but that's why I have a sub.Took the door panels back off to put a breathing hole in the foam back cover on the door speakers. I was instructed by Crutchfield to do this since I said that the bass isn't what it use to be with the new speakers and it makes sense that the cones have to breath some.
I ordered my new head unit and awaiting it's arrival.
How big a hole did they tell you to cut/drill for your 6 1/2" speakers?
They said to cut a hole about the size of a quarter where the wires go through and make sure it is at the bottom of the foam for water purposes.


