Hi. I have a rather bizarre question... Is it a good idea to fill the inside of the door with poly foam? I know its used for sub and speaker boxes, but can it be used to increase performance in side doors since the inside of the door will become something like a box to the speakers( running 6.5")? ( I'm talking about gluing it to the walls of course)

 

Would be like a sponge....

 

just make sure its water and mold resistant

 

Fire resistant too, the problem is most likely it will retain moister in your door causing it(the door) to rust away. The moisture won't be good for your speakers either.

 

Oh.. well i was going to put carpet underlay as a "sound deadening foam" :]... I was just wondering about the Polly foam (the cotton like stuff to stuff pillows- that's what i meant).. I am aware of the moisture problem, but i think the carpet underlay should be ok...

and i just tested my new 6.5" and 6x9... I am pretty amazed since I was running only stock speakers in my cars before ... I'm making lots of pics so ill post the install soon.... nothing big- limited budget... the only problem I have left is that I will actually have to buy the sound deadener, all of my "make it yourself" ideas did not work out :/

 

i used rock guard. works good to solidify the metal. and does the job. put a good 5 --- 8 layers and you should get some difference.

 

Deadening / mass loading will help with the low end, but if you're looking to cut out some higher frequency road noise, you'll want to go with a foam-based product. I put some Elemental Designs V4 on my door after stiffing up the panels and found it helped a little bit. There are many similar products out there.. check out Parts Express (Parts Express: Featured Categories)

 

There are different types of foam and I am not sure I can say this is a grand idea with any of them.

so if you do it....first off I would recommend a closed cell hydrophobic foam in that location as previously stated a sponge would be bad, this area does see a lot of water flow from the seal down the door skin to the drainage holes on the bottom of the door. but over time mold and moisture issues will occur.

if you use the material in moderate levels and don't stop the flow of moisture then it isn't a bad idea. The damping materials tend to work well in this area (as stated) and the foam/ batting materials work from 600 Hz up so address the problems with the correct material. I would limit the material to an inch or so max... and even then be careful if your car starts to smell this could be a reason (or that big mac you forgot about last month under your seat).

oh yeah, I hope it doesn't get into and then monkey up the windows operating mechanism

 

ok... well my budget wont let me do the real deal here since its quite pricey- that's why i picked up the carpet underlay, so i will try to figure something out considering the moisture problem... oh danyman thnx for the idea! I will definitely check this stuff out!