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Discussion Starter #1
I'm just starting to Dynamat the car (interior is already removed).

I have some of the old factory insulation by the rear wheel well. It is in very good condition.

Should I remove the insulation, leave it, or apply the Dynamat over it?

Also, in what order should I apply the Dynamat. I was thinkning first doors, then trunk area and lastly floor. Is this correct?

Thanks
 

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First to answer your question I would certainly leave the factory insulation -- it can't hurt. Apply the Dynamat underneath the insulation. I agree with your order of operations 1) Door 2) Trunk 3) Floor and it seems to be the general answer around here. Keep in mind Dynamat is only a vibration dampener and will not necessarily block out unwanted road noise.

And last a plug for Raammat/Second Skin in case you haven't used their products. Every bit as effective as Dynamat extreme and probably at about half the cost.

RAAMaudio - Quality and Value in Automotive Sound Deadening

Sound Deadening Materials for Noise Reduction from Second Skin
 

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And last a plug for Raammat/Second Skin in case you haven't used their products. Every bit as effective as Dynamat extreme and probably at about half the cost.
Cheaper yes, but as effective? How do you figure?

Mahna - is this Dynamat original or Xtreme? What vehicle?
 

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Discussion Starter #4
Mahna - is this Dynamat original or Xtreme? What vehicle?
It's Dynamat Extreme (sorry should have said). I picked up a pack of 36 sq.ft for a REALLY good deal.

My vehicle is an 89 Camaro IROC.


The factory insulation is stuck down so if I remove it I can't put it back (its only on the top of the wheel wells).

Should I still remove the insulation or Dynamat over it?
 

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Here you go .....thanks



Looks to be they're attempt at a barrier. Some cheap, thin vinyl over maybe 3/8" cotton?

If you apply DX to that humped section, then complete the job with a better barrier product and trash the OEM stuff. Just DX alone will be futile against the noise the tires make. You can expect maybe a 2-3 dB difference at best IMO. With a barrier you can best that by 4-5x.

The place for your DX is that flat section on the bottom of the floor in the foreground of the second pic. Next time you're in there, bump the middle of that with your hand and you'll know what I'm talking about as it will probably sound like a drum. Cover 70% of that and you'll have used DX effectively. Add complete barrier coverage over the entire surface of the floor and sides and you'll really put a dent in the ingress noise level.
 

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Fox, your being awfully kind regarding sound treatment today....must be in a good mood :)
LOL, jerk. :p Just cause you said that.....

Back in the day I put probably 100 sqft of 1/2" jute (same stuff pictured above) in my car...rail to rail, front to back...complete coverage of the entire hatch area. Last year or so I went back and I ripped the floor section of jute out, ripped the eDead garbage off the best I could and redid the whole thing.

Before...


After...(a $20 barrier blanket I made from Reynolds Wrap and CCF)....


Instead of removing the jute from the side walls, I decided to apply my left over barrier scraps to the back side of the factory plastic pieces like so:



That's enough show and tell. I'll ruin my conceded ******* reputation. ;)
 

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Fox have you ever been able to rta or dB, before, after ,during all this work you did?
 

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Cheaper yes, but as effective? How do you figure?
I figured (with a limited but slowly growing knowledge of sound deadening :)) that as far as a vibration dampener went the effect between Damplifier/Raammat would be quite similar to that of Dynamat Extreme. I'd ask what way they differ, but you said you weren't trying to ruin your reputation around here! So, the search begins.
 

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I figured (with a limited but slowly growing knowledge of sound deadening :)) that as far as a vibration dampener went the effect between Damplifier/Raammat would be quite similar to that of Dynamat Extreme. I'd ask what way they differ, but you said you weren't trying to ruin your reputation around here! So, the search begins.
You posted the links so I'm assuming you'll check out their specs.

Without actual damping performance ratings (DLF/ALF data) for SS and RAAM products, it's difficult to say for certain.

Up close and personal, however, RAAMmat BXT and Damp Pro are two different animals. DP is thicker (foil and adhesive), heavier and uses a different quality butyl composite (not saying *better* because I don't know if it is or isn't). It seems to me that if honestly you wanted to match them up, you'd need 2-3x the amount of BXT than DP.

Same thing goes for DX vs BXT. At least 2x BXT to match DX IME.

I don't have any data, but it seems Rudeboy's foil thickness vs vibration decay rates/sounds in his own testing seems pretty suggestive that foil thickness plays a critical role.

I just had trouble with the "every bit as effective" statement as I think it's misleading. Many people think that more coverage/$$$ = a better deal but that can easily be shown to be false on many grounds.
 

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Fox have you ever been able to rta or dB, before, after ,during all this work you did?
Nope. Way too many products in and out and car upgrades to figure that out. I might do a before and after RTA analysis with the return to stock of my catless midpipe, though. Without a complete stock baseline all I can really chalk that up to is how much of a fight I was waging against exhaust noise.
 

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Discussion Starter #14
If you apply DX to that humped section, then complete the job with a better barrier product and trash the OEM stuff. Just DX alone will be futile against the noise the tires make. You can expect maybe a 2-3 dB difference at best IMO. With a barrier you can best that by 4-5x.
What is a good sound barrier to apply over the DX to the wheel well areas?
 

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I am sure fox will chime in, but what I have started using(thanks to fox's wisdom) is Cascade's VB3/VB3.5. for wheel wells and trany humps it's the only thing worth my time. Easy to mold. LLP is a good barrier but I will use it on flat spots only.
 

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Sounds like some very good wisdom from you, Wayne. Good call.

But since this is a DIY forum, you can get a comparable barrier decoupler solution done for cheaper (usually) but, truth be told, it might not be worth your time in research and application. If you're game, see "road and tyre noizez" thread for info. If not, see above post.

And yes, I just dodged another direct product recommendation....once again.....he....he.....;)
 

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Should I still remove the insulation or Dynamat over it?
Don't know if anyone addressed this question directly... it won't do you any good to DX over that insulation- it needs to be in contact with the metal to do its job. As Fox said, its a vibration dampner, so it needs to be on the metal to prevent it from resonating. follow up on top with additional sound insulation for the 1-2 punch.
 
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