Sound Proofing

[Moose Drool]

What have you all done to rid the interior of unwanted noise? I used sound insulation under the new carpet. But the rest of the cab is all metal. What else can be done?

 

[Frankenchevy]

Headliner or lizard skin for the roof...

Stuff like dynamat controls vibrations on flat panels. Closed cell foam will help to deaden the sound penetrating the cab. Most pros I’ve talked to use a combination of several mediums.


This is what I’ve gathered from car audio shops:
Dynamat doesn’t require full coverage, it’s just a vibration dampener and will be effective at that without going over the top. Actual sound deadening material needs to be done thoroughly. Stuff it everywhere. In doors, between the crevices on the dash and cab, cab corners, under carpets.

I’m using paint on deadener, peel n stick, closed cell foam, bubble wrap type duct insulation with spray adhesive where it needs to be tight(1/8”), carpet padding, etc.
I still haven’t figured out what to do about a headliner. Although, I was fine with the noise level before I tore the truck apart.

After all that, it still won’t be an S class Mercedes.

 

[WFO]

Dynamat doesn’t require full coverage, it’s just a vibration dampener and will be effective at that without going over the top.

That makes sense to me.
I've noticed that stainless steel kitchen sinks just use one 4"x4" piece of sound deadener on the bottom. One double sink I installed was missing the piece on one of the sinks, and you could tell the difference between the two when you ran water.

 

[yevgenievich]

Following worked for me and about as good as I think it will get.
https://www.gmsquarebody.com/threads/1991-v2500-suburban-sound-insulation-project.19898/

 

[shiftpro]

Closed cell foam is actually very resonant, so it doesn't help with sound control. You need mass, weight, like your Dynamat.
You can pull your door panels and with the windows rolled up you can get a piece of Dynamat on the lower art of the door skin. It's a pain
getting it in there but every little bit helps.

 

[Frankenchevy]

So if your standing inside of a sheet metal box with someone running a lawn mower outside, it would be quieter in the hollow box than in the box lined with foam?

 

[eskimomann209]

I haven’t used it yet
But the secret is supposed to be MLV (mass loaded vinyl)
I’m putting the “dynamat” where I think I need it. Even though the popular vote is go 40% of metal I think it does keep some Heat out so I’m going to cover the entire floor, add some industrial carpet insulation, maybe some MLV if I can find it reasonable then the carpet.
The MLV can always be done later.
For the back wall I’ll probably only do 40% with dyna since it’s not exposed to the engine or trans heat and the bed is there to protect it from direct sunlight.
This is just my plan, I’m not worried about noise tho.. when I get Vintage air in I want it cold in the summer and warm in the winter
My radio will make enough “noise”

 

[eskimomann209]

So if your standing inside of a sheet metal box with someone running a lawn mower outside, it would be quieter in the hollow box than in the box lined with foam?

Put some foam around your ears with the same experiment

 

[Frankenchevy]

I did use the wrong terminology. I didn’t mean closed cell foam. This must’ve stuck from all the late night zombie research I was doing.

I think what I was referring to was high density foam, but I’d have to check my notebook when I’m around it.

I stand corrected.

 

[Frankenchevy]

Put some foam around your ears with the same experiment

Lol, yeah ear plugs work. Sound is produced by the vibration of a medium. Since our trucks are metal boxes, I thought it more relevant.

But maybe it was silly.

 

[yevgenievich]

Combination of heavy layer, followed by foam, followed by have vynil(mlv) gives good results. Extra seal around upper door area and line the doors. I have just about reached the point of diminishing returns on mine. Thin window glass are main sound source for me

 

[eskimomann209]

Lol, yeah ear plugs work. Sound is produced by the vibration of a medium. Since our trucks are metal boxes, I thought it more relevant.

But maybe it was silly.

Hey brother I was just teasing.
I understood what you were saying
And have heard/ read of people putting closed cell foam and some other insulator on the firewall for heat/ sound.
I’m no acoustics nut and certainly don’t measure vibrations by anything other than opinion.
And In my opinion ANYTHING is better than nothing

 

[shiftpro]

So if your standing inside of a sheet metal box with someone running a lawn mower outside, it would be quieter in the hollow box than in the box lined with foam?

The mass of the foam would damp the noise slightly, if that. I didn't say the foam would make the cab louder. Your example (apples to oranges really)
of foam inside the box would do more to control the sound inside, taking the edges of the high frequencies, but it wouldn't cut DBs coming through from out side.
I built many studios and sound proof grow ops. Take my advice and stick with mass loaded matting. Blue Skin works too.

 

[shiftpro]

Combination of heavy layer, followed by foam, followed by have vynil(mlv) gives good results. Extra seal around upper door area and line the doors. I have just about reached the point of diminishing returns on mine. Thin window glass are main sound source for me

That becomes constrained layer dampening... works awesome!

 

[yevgenievich]

And you have to have complete coverage to really get a difference( not on heavy damping material, that is for panel vibrations)