So, if I wanted to reduce the roadnoise in my '96 Bronco, what would be the most cost-effective way to do that?
Tires on it are new, so replacing them isn't really an option.
I'm thinking more about judicious application of dynamat/close-cell foam/etc.
I'd rather not just blindly coat the entire interior in the stuff; it seems like accoustically there should be some key places to apply it.
Put heavy rubber/tar sheeting in the middle of any large flat areas in the pan and body (including the doors). It doesn't have to be a large amount, a 1 ft by 1ft square for a door is plenty big.
Add jute matting under the carpeting.
Most important: SEAL ALL AIR LEAKS. Even a small path to the outside will let in a huge amount of noise.
Best to avoid Dynamat unless you really don't like your money. It will likely be a bit better for vertical surfaces in very warm or very cold climates (sticky wise), but I think you can do just as well with the Home Depot stuff and a good glue and save a LOT of money.
aircooled wrote: Put heavy rubber/tar sheeting in the middle of any large flat areas in the pan and body (including the doors). It doesn't have to be a large amount, a 1 ft by 1ft square for a door is plenty big.
Isn't that just adding mass to change the resonant frequency, though? I thought that was just to prevent rattling, for like if you had a subwoofer.
aircooled wrote: Add jute matting under the carpeting. Most important: SEAL ALL AIR LEAKS. Even a small path to the outside will let in a huge amount of noise/
That could be a big part there... seals at the base of the window are pretty shot.
www.koolmat.com
www.thermotec.com
www.designengineering.com
All nice folks who advertise in GRM / CMS
ReverendDexter wrote: Isn't that just adding mass to change the resonant frequency, though? I thought that was just to prevent rattling, for like if you had a subwoofer.
It keeps the large flat areas from acting like a drum and transmitting the sound through. That is why you don't need a lot, just enough to dampen the vibration.
I just noticed in a recent Wheeler Dealer that the kit they installed had tiny strips for small flat areas, so you might want to put some in the small areas also.
I've seen foam wedged in hollow spaces to keep noise transmission down as well. Worked pretty damn well in my XJ6.
Tire noise usually comes in through the wheel wells. Pull the carpet off of them and use either truck bedliner or rubberized undercoat, make sure if you use undercoat it gets to dry for several days. Then put the stock jute and carpet back. As was said earlier, tiny holes let big noise in. Wait till dark, put a shop light etc under the car, climb in side and look for light shining through. Block 'em off.
The only thing I don't like about jute is how heavy it is. But it does work very well.
If you decide to go with dynamat,check out rammat. Less expensive, I've used it & been pleased.
This is available in smaller rolls but it works and is cheap on a per foot basis. It is self adhesive rubber/asphalt like material that is flexible and waterproof.
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=202800772&langId=-1&catalogId=10053&ci_src=14110944&ci_sku=202800772&cm_mmc=shopping--googlebase--D22X-_-202800772&locStoreNum=1950
You'll need to log in to post.
