Hello Honda-tech,
I've had a set of 6 1/2" Polk speakers installed in my front door baskets (that were originally designed for 5 1/4") for several years. They fit snugly but with no issues, but I recently noticed when I opened the door panels that the baskets were quite wet (it rained recently) and some of the water was on the speakers themselves. I ordered a set of Boom Mat foam baffles, and installed one between one speaker and basket. There's no space between the speaker driver and the foam, or between the foam and the back of the basket. Everything is very snug. See here: http://imgur.com/8Qp9A
When pushing gently on the speaker cone, there is obvious air resistance.
Two questions:
1. Will the air resistance from the nearly-airtight enclosure diminish the volume of these speakers?
2. Will the complete lack of air current harm the drivers?
Thanks!

 

You should be fine. If you're worried about moisture, get some marine speakers instead. Polk Audio is one I would look at.

 

If anyone's interesed:
I installed the foam baffles in the plastic baskets for both front speakers. As I said before, fit was very tight - there is no space between the back of the driver and the foam, or the foam and the plastic basket. The result is MUCH less bass response than before, treble seems unaffected. I've been using them for several months now, and the drivers seem to be holding up fine.

 

If anyone is interested. I recently installed the foam baskets and NVTurbo is correct. Moisture problems: replace all door rubber and gaskets, is cheaper and your car will be much quiter. The new speakers are composite cones, the old had cardboard cones. So no problem there. Spray the back of the speaker with WD-40 or liquid RTV and that will preserve them fron corrosion for about maybe 7 years +. The foam cups restricted the bass termendoulsy (blocking the air flow), I guess I could cut some specific holes on them, but figured it was a waste of time.. I didnt like them.

 

Check speaker phasing, use balance control on HU to balance all the way left and right, if bass is better when all the way left or right then when in the center, speakers are wired out of phase, reverse the leads on one speaker, it makes no diff. which one. 94

 

Why not simply cut out the back of the plastic basket?

That's what I had to do to fit thicker speakers into my doors. The foam will keep it protected, the plastic isn't doing anything but getting in the way now.