Sound Deadening Question : Door panels

[spoonraker 10+ year member]

Well I took my door panels off to start deadening and realized that they have massive holes in them. The front doors have 3 very large holes.

Now I know ideally you are supposed to cover all the holes with metal and weld them so that it is sealed...but that is not something I'm capable of doing or going to pay for.

So my question is this. Which of the following would be the best?

1. Deaden the inner door skin AND the outer door skin as much as I can, leaving the holes open.

2. Only deaden the inner door skin, but cover the holes with large patches of deadener.

Keep in mind the deadening is 90% designed to keep road noise out, I'm not too worried about vibration since my mids will be in fully sealed custom door pods and I have speaker pads to install as well. The pods connect directly to the inner door skin and the panel/speaker grill mounts over the top of it. The tweets are in the A-pillars.

I will be using DAmplifier, ensolite closed cell foam, and I have two speaker pads as well.

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[Rudy 10+ year member]

I don't think anybody wants you to weld the access holes shut. I use the aluminum flashing you can get at Home Depot. You can cut it with scissors. I double it up, making a sandwich with silicone caulk in between the two layers. Put some sound deadener on each side and you have a solid panel to fill the hole.

You can either use self tapping screws to hold them in place, or use silicone caulk (be sure to let it dry completely) or both. Works great and sealing that inner surface will be a big help in reducing road noise.

 

[LoudCrownVic 5,000+ posts]

I just put 2 layers deadener over it. Worked fine.

 

[Rudy 10+ year member]

I just put 2 layers deadener over it. Worked fine.

Not terrible, but much less rigid than what I'm suggesting and I don't like to leave the adhesive exposed to the inside of the door - no real reason, just a little compulsive about things.

 

[o. l. t. 10+ year member]

You need to be as rigid as possible. If you want to see what not being rigid does to sound, stick a 1/4 inch piece of plexi in the place one of your walls are on your box and remove the wood leaving only the plexi as the wall. Sounds waves do not care where they are in the car, it's the same effect everywhere.

 

[spoonraker 10+ year member]

So what's the verdict, just deaden right over the holes? Multiple layers if possible?

I'm doing my front doors and trunk for sure. I have 80 square feet. If there is enough left I'll pull up the carpet and do some of the floor in the cabin. If the results are significant I'll probably order some more down the road and deaden the crap out of everything.

 

[AwaySooner 10+ year member]

If you don't want to cut metal and use screws into the panel, then just go to hardware/art store, get some thin plywood or mdf, cut then into shape, put few layers of Damplifier on the inside, stick the board on, then another few layers on top of the mdf/plywood on the outside. Pretty easy.

 

[James Bang 5,000+ posts]

since you have sealed doorpods, i'd say just leave the holes there .

 

[spoonraker 10+ year member]

since you have sealed doorpods, i'd say just leave the holes there .

That's kind of what I was thinking. It's not like the speaker is going to be pushing air back into the door panel and vibrating the crap out of it. The only vibration of the panel will be caused by the speaker pod being mounted to it.

 

[Rudy 10+ year member]

That's kind of what I was thinking. It's not like the speaker is going to be pushing air back into the door panel and vibrating the crap out of it. The only vibration of the panel will be caused by the speaker pod being mounted to it.

You said you were concerned about blocking road noise. Two sealed surfaces will work better than one. It definitely will not make any difference in midbass response.

 

[spoonraker 10+ year member]

When I posted this I don't think anybody read the part about me having sealed pods so my main issue is road noise...

Let me rephrase and get some more opinions.

Is covering the access holes a major part of reducing road noise? Or should I just put as much deadener on both the inner and outer door skins as I can and leave them open? If I do need to cover the holes, what is the best way of doing so? Would just deadening straight over the holes be enough?

 

[UndercoverPunk 5,000+ posts]

.... your question was already answered.

 

[spoonraker 10+ year member]

I think olt and james bang confused me.... but I'm gonna cover the holes

I think I'm going to do the thin piece of wood trick

 

[Rudy 10+ year member]

I think olt and james bang confused me.... but I'm gonna cover the holes
I think I'm going to do the thin piece of wood trick

If you use wood, you'll need to treat it with resin or something else to be sure it is completely impregnable to water. Otherwise it will swell itself apart as it absorbs moisture.

 

[spoonraker 10+ year member]

I'll check out that aluminum flashing then, I live about 2 minutes from home depot and lowes. Is there a specific name for it or will they know what I'm talking about if I tell them aluminum flashing?