Just a note – I posted this a couple of years ago, and the insulation, etc is still working just fine.

Thought I'd share some sound deadening tips for the big bronco.
I have an 89XLT with the molded plastic interior panels. Between the aggressive tires, road noise, and the hollow sounds coming from the back panels, it was hard to carry on a conversation at 60 mph ('course, considering my ex-wife that wasn't such a bad idea )

Anyway, here's how I solved the problem. Went to Home Depot (any large home improvement store will do) and bought the High Density polystyrene foam that's used for exterior insulation. It has a "skin" on both sides to help it maintain its integrity it comes in various thickness and panel sizes. I picked up a 2" thick 4'X 8' and a 1" thick piece 4' X 4' and a can of 3M #77 spray adhesive.

Take your inner panels off in the rear (more room to work with the seat out). Use a jigsaw or a bread knife and start cutting pieces to fit into the body cavity on each side. Use the 1" if the 2" is too thick. With a little care you can fill up just about all the dead spaces in there. Seal the cut edges of the foam with duct tape, spray the adhesive on and put the foam panels into place. Replace the plastic panels and you're done. It will make a huge difference in the interior sound level of your rig.

You can do the front doors as well - you need to use the 1" there to make sure you clear the window when it's down. A little more work but it’s worth it. The only real problem comes from all the "sawdust" you get from cutting it. The stuff is super light and gets everywhere ;-)

I've had it in mine for a couple of years without any problems. As an added little bonus, you can construct a 'box' of sorts around the rear speakers to help the sound quality there.



Hope somebody else can use this idea...

msautry

 

Redbob - there are many products on eBay claiming to be the same as dynamat at half the cost. That much is believeable, since Dynamat is a brand name and strikes me as being something that could be sold for a lot less. I mean, it's just a small sheet of some sticky stuff...

Anyway, do you know if these or any other brands are actually comparable to Dynamat? I'd like to buy some, but I also don't want to be sticking some worthless stuff in my truck to save some money.

 

I like the idea of creating a box with the "Sheathing" around the rear speakers for a "fine sound". I bought some Pioneer speakers and they sound like the original factory speakers.

So will the 2 inch thick "Sheathing" fit behind the rear panels?

I saw a camping foam for the sleeping bags. I think that might work too.
It is 1/2 x 30 x 72 for $4.88!

 

Yes, there are a number of other companies making products at least as good as Dynamat: Soundcoat, Rieter, and Blachford are three that come imediately to mind, and whose products I have used successfully. Another very reputable company is E.A.R. Specialty Composites whose "Isodamp" products are no doubt very good.

Since these are all "OE" automotive suppliers, though, I'm not sure if they sell small quantities to individual users.
Somebody on E-bay might well be buying this stuff in bulk and repackaging it, though.

These same companies also make acoustic foam products - except Rieter which specializes in fiber-type absorbing materials - and could be good sources of that type material.

Finally, 3M makes a damping foil, adhesive-backed, that is very effective at reducing panel vibrations, but it seems to me it's pretty pricey stuff.

Regards,
Robert

PS: Keep in mind the 3 general classes of acoustic materials I listed previously, and be very suspicious of claims for a material that doesn't fit in one of those classes. For example, if someone tells you about a "lightweight barrier" material, or let's say a closed-cell foam that's supposed to "absorb sound" or be a sound barrier, you can be VERY skeptical...

 

This is an old thread, but worth revisiting. I too want to sound-proof my Bronco better. All of the road noise makes it very difficult to hear what my two year old daughter is trying to tell me when driving 55 or more. You almost can't carry on a conversation when driving on the highway in rain at all!
So whiich of these would be best for the fiberglass top? It would be a temperature / resonance barrier.

 

Why would you want to deaden the the wails of your Broncs big Moter when you flog the poor thing....Sweet music to my ears.....

 

I have quite a lot of Dynamat and Dynamat Xtreme throughout my Bronco. Honestly, I could not tell that much of a difference. I put it in when I installed a powerful (610 watts RMS) stereo with a sub and I wanted to avoid having the sheet metal buzzing, as well as getting tighter bass. It seems to work in this capacity, I don't get any sheet metal buzz and the bass sounds great.

Where I installed the Dynamat - I covered both doors on the sheet metal behind the plastic (not behind it on the door skin). I lined the floors in the front, from the dash to the center console. I have it under the trim in the back, where the top bolts are. I lined in and around the area where the rear speakers are. I also lined the bandpass box that my subwoofer is in.

Eventually I will do the whole truck.

 

To reduce the noise from rain beating on the roof, you need viscous damping sheet on the roof panel, backed up by sound barrier. See the previous posts for descriptions of which type materials do what, and decide what you need based on the type sound you are dealing with.

 

i have had good fortune to discover the attributes of can foam insulation. several brands are availailable and are very nearly the same product all-in-one-can. it is a tenacious adhesive if you want to fasten a patch over that old hole in the floor, or a lacerated piece of sheetmetal, just follow the directions to prepare the surface (clean/dry/dirt-dust free) and squirt the foam into the 'joint' to be bonded. using a clamp or weight to join two pieces or wide tape to 'dam' the flow in a contained area, will help with cleanup later. even tho it takes awhile to setup solid, it has awesome strength. i have seen dash pads glued down, headliner bonded into place, floor pans and even a tailgate fastened down permanently. a bit of latex paint will minimize the UV and ozone deterioration where exposed to sun and weather. not the cheapest glue around, but handy as a spraycan can be, and awesome hold-down power, with sound-proofing properties to boot.

 

I just replaced the power lock actuator in my drivers side door. While apart, I bought some 6" wide foam seam sealer and carpet tape. I applied two rows of tape per roll of sealer to the inside of the outer door skin. I got 4 rows of it in ther from front to back.
I also used some patches of it and some duct tape to seal som holes in the inner door stamping before installing the door panel back in. Oh yea, I put an extra layer behind my Infinity door speaker. I can't say much about interior noise yet, because my passenger side door is torn apart still, but I will say the drivers side door closes like a bank vault now! I plan on doing the same thing on the passenger side.