Alright guys, I know what you are going to say, but I did a search and have seen the great, repeat great write up that BOB_98SR5 did.

But I have two questions, has anyone used any spray on stuff for inside the doors, the outer metal? I know someone mentioned "Great Stuff" polyurethane foam for the back sections. Has anyone used anything else back there?

I have heard the great stuff is not good to use because it gives off toxic odor in the heat (I dunno if I should believe that since it is used everywhere)

 

Almost all plastics give off toxic fumes when burning...so don't burn them. I put great stuff in the rear quarter panels...a little bit at a time since it expands for hours afterward and can generate enough pressure to distort your panels. However, I have never been satisfied with my soundproofing job. I think I'm still getting a lot of noise from the tailgate.

 

I have yet to understand the need to "soundproof" your vehicle...

Different strokes for different folks!

I just turn up the radio louder...

 

Glenn,

Thanks for the compliment on the write up. That one definitely took the longest to document!

I don't think the Great Stuff is good for inside your doors b/c it will be hard to control the expansion. Moreover, there is a good possibility that the window action may be compromised by the foam.

I considered putting a layer of carpet padding in there but given the possibility of water running down and soaking it (future mold issues), i decided to just do a layer of PNS. I may do another layer of PNS this summer.

FYI: i'm pulling everything off in the early summer to see how the stuff is holding up. My guess is that everything is fine but one never knows 100% until you look!

Brian, two reasons for soundproofing: eliminating road noise to allow your stereo equipment to be better heard and for....eliminating road noise! When me and the misses take a long road trip, she remarks occassionally how much quieter it is. And then dozes off.

Bob

 

Waskilly...
When your ears start ringing from your rock 'n roll days and cranking 4 14" with 200 watts running at 4 ohms, you'll enjoy a little peace and quiet.

 

One thing, I did notice that you used padding on the floor, others used PNS, what is the benefit of each?

Glenn

 

glenn,

on the floor and the roof, i used a combination of mcmaster hi-temp mastic and carpet padding (used 3m 90 adhesive).

on the vertical surfaces, i used peel n seal.

bob

 

Playin it like that on a regular basis and pretty soon you won't hear any road noise, or much else for that matter.

 

http://www.shagadelic.org/VW/info/gmbulley-soundproof/
This is a great article on soundproofing vehicles. It's basis is the VW bus, which if you've ever been inside one you know is one of the noisiest things running around.

I personally would not use something like greatstuff or any other spray foam. I've got a good bit of experience with foams building and repairing boats, and working on cars that had it done to them. They don't fill voids completely, water travels around the surface, and things rust nicely because of it. Because of the hard nature of the foams, particularly the skinning types, they transmit noise just fine. Only the soft open cell types are particularly effective at insulating noise.

I have soundproofed reasonably well with the asphalt type soundproofing materials in a manner very similar to what is described in the linked article. The spray can stuff works quite well. You can make it apply far better by setting the can in hot water for few minutes to get the tar as liquid as possible. Makes quite a difference in how it applies.

Tailpipe location can be a big source of noise btw. If you've got it ending within the body, extend it. It changes where the sound waves exit and where they therefore reflect.

 

No to be a wise ass, but I've never heard of a 14" sub. 12" and 15" maybe, but not 14". Get your facts straight before laying the smack down.

 

Cebby...
Not to hijack the thread....
1976...2 Kustom Bass Cabinets each had 2 14" speakers. 1 Kustom head that put out 100 watts @ 8 ohm's and allowed you to plug 2 cabinets in and lower the impedance to 4 ohm's. Used in jazz bands, Chicago-style rock and yes...even disco. Got my facts straight...check your attitude.

 

WHAT!!!???

 

And just in case I wasn't very clear about the Great Stuff...I believe it quieted the panels down...You can tap that rear quarter panel now and it gives a nice solid thump. But I don't believe it helped make the interior quieter. I also used PNS on the rear deck and rear passenger compartment. Then I used a foam backed 1/8" insulation and finally 1/2" carpet foam on the rear deck. I still get a lot of road noise from the rear. I don't even enjoy playing the stereo at highway speeds.

I also question what the long term effects of the Great Stuff will be...Of course it's a 9 year old vehicle (in great shape though). GS is polyurethane foam and as part of the curing process, it absorbs water. I'm not sure how or if the water is incorporated into the molecular structure. I also dread getting hit in the rear quarter and needing to repair. The GS was my own "experiment". I can't really recommend it as a soundproofing material for panels.

Incidentally, Bob's write-up on the 3rd gen is very applicable to 2nd gens.

 

14" subwoofers:

By JBL

From, Definitive Technology

~Bill