Dynamat

At approximately 80 Lbs per 20 foot roll

And considering the major "noise complaint" is the buffeting with the rear windows down (which also occurs in lots of other vehicles as well)

Seems to be a lot of weight to add to a vehicle with so much ridicule of the MPG
I recognize you are only asking about the rear doors...but other areas on the Nox / Terrain lack "sound proofing" also such as the wheel wells...

Now if you don't care about MPG
and are instead trying to build a "sound stage" in the Terrain / Nox...that's different

But in that scenario...the floor / roof / doors / heck every interior panel including the firewall should be completely stripped and "matted" to do it right.

I've not read about anyone doing it yet...maybe on another Nox / Terrain forum...but not here
Maybe I missed the thread though

Yeah, a lot of people don't think about how much weight soundproofing actually adds to a vehicle...and with pressure on manufacturers to meet increasingly difficult MPG averages, future vehicles won't get much if any quieter than they are today. Think about any car that you consider to be really quiet and isolated from the environment, and chances are it will be one of the heaviest in it's class. Incidentally, the Equinox/Terrain are generally considered quieter than their competitors (Rav4, CRV, Escape, Tucson etc..) and I found that to be true when doing test drives.

As for your original question, if you do a search here for "dynamat" you'll find a few threads discussing using it...but no real info from people who have done it. There is a thread somehwere that has a tutorial of sorts for removing the door panels, but I can't seem to find it.

This may sound weird to a lot of people but up here in Alaska we use this stuff on our roofs, its on a roll, looks like Bear Bond in Nascar, its like a super sticky on one side of rubber sheeting, more like some sort of fruit roll of rubber and adhesive, called Ice and Water shield by Grace.

On my Silverado dually I replaced my door speakers with something better but while I had the door panels off I applied this stuff in at least three layers all on the metal inside doorskin, which is almost 3/4". Stuff when stuck to each other is nearly impossible to remove.

A poorman ******* version of sound deadening, I bought a roll at lowes for just over $100, After 9 years of it in I still have a limousine type of silence inside my Silverado. You can get better stuff at a higher cost though, to each their own.

And words of wisdom when reinstalling high power speakers and door fasteners, use locknuts and locktite.

teetertotter said:

What can you do with the Drivers and front Passengers Doors so they don't sound like a tin can every time you shut them?

Click to expand...

Actually, if that is what you are after - that is where Dynamat will help you.... Dynamat Xtreme. I put a few small patches of it (It is super-self-adhesive) on the inside of my rear quarter panels, thinking it might knock down road noise.... which it didn't, but when I did a 'before/after' knuckle thump on the exterior of the rear quarters, it went from a 'tinny' sound to a dull 'thump.'

This would work for your doors in the same manner.

It is a flat out 'bitch' of a project in that you have to disassemble your door panels, and possibly remove plastic coverings and some hardware to get access to the inside of your doors.... not to mention the non-sticky side of the Dynamat is laminated with a metal foil which is razor sharp.... so expect some minor lacerations on your hands and fingers before you are done.

But again - this will change the sound of the metal from a 'tinny' sound to a 'dull thud.'

I didn't put any in my doors but you can search Dynamat installations on YouTube and you will see video evidence that this works.

HOWEVER - it will not defeat any ambient noise entering your vehicle.... it just changes the accoustic signature of the metal it is applied to. Good for knocking out the metal vibrations if you have a ghetto sound system installed in your trunk too.

All I can tell you is that I speak from experience. Look up my 'Dynamat' post. I expertly aligned and installed the entire cargo floor and halfwalls, including the inner rear quarter panels. Results? Nada.... no deadening of the encroachment of road noise.

I attained very limited, but better results going to Joanne Fabrics and purchasing 'pillow' stuffing.... and jamming it into the sidewalls of the cargo area between the plastic cargo sidewall trim pieces and the metal framework of the NOX.

GM doesn't do much more than that.... I had the entire side panels removed from the rear to the front... and all they have for sound deadening is a thin, cheap-azz material about 1/4" thick.

I talk from experience - not conjecture.

You can spend hundreds of dollars if you want... but in the end.... you will wish you would have listened to me.

I talked to Dynamat techs directly (after my install) and they told me I would not get results unless I lined every square inch of the car: cargo, rear hatch, doors, sidewalls, roof, etc.

Ok... so be prepared to spend over $1,000 on an experiment. Good luck.