Sound Damping for the VX

[Tone]

You must use a particular Dynamat (not the bottom or mid grade) for the roof to withstand the excessive heat - see their web page for more info. Don�t forget to compare the specs when looking for �discount� materials - there is a big difference even within Dynamat�s own product line. All sound dampening materials are NOT the same.

[kpaske]

Tone - What specs in particular should we look for? I've read some reviews, but I don't know much about the way these things are measured. Also, the special application is for under the hood, not the headliner, right? Or does the headliner need a special type of damping also?

[kpaske]

I did a little research and here is what I've come up with.

Dynamat Extreme:
Description: a viscoelastic elastomeric butyl and aluminum
constrained-layer vibrational damper.
Installation: no heat required
Odor: none
Price per sq. foot: $3.47 (based on price of $125/36ft)
Thickness: 1.14 mm (.0044 in.)
Mass: 0.45 lbs/sq.ft.
Acoustic Loss Factor (ASTM method E756@ 200 Hz):
0.240 @ +32F (+0C)
0.257 @ +50F (+10C)
0.417 @ +68F (+20C)
0.259 @ +86F (+30C)
0.194 @ +104F (+40C)

Brown Bread:
Description: a viscoelastic deadener with a supercharged
bitumen based adhesive, an aluminum constraining layer and
a unique composition with suspended mineral particles.
Installation: heat required
Odor: tar-like
Price per sq. foot: $2.14 (based on price of $150/70ft)
Thickness: 1.60 mm
Mass: 0.40 lbs/sq.ft.
Acoustic Loss Factor (ASTM method E756@ 200 Hz):
0.230 @ +32F (+0C)
0.260 @ +50F (+10C)
0.390 @ +68F (+20C)
0.320 @ +86F (+30C)
0.240 @ +104F (+40C)

B-Quiet Extreme:
Description: a thick composite mat which consists of rubberized
asphalt with an aluminum constraining layer.
Installation: ???
Odor: ???
PRice per sq.foot: $1.25 (based on price of $125/100ft)
Thickness: 1.15 mm
Mass: 0.30 lbs/sq.ft.
Acoustic Loss Factor (ASTM method E756@ 200 Hz):
0.160 @ +32F (+0C)
0.190 @ +50F (+10C)
0.290 @ +68F (+20C)
0.200 @ +86F (+30C)
0.140 @ +104F (+40C)

I searched for specs on RAAMmat, FatMat, RattleTrap, Thundermat, Cascade GatorSkin, and SecondSkin but could not find enough information about them (particularly the acoustic loss factor) for a fair comparison. Whenever possible I took data directly from the manufacturer's web site.

The data above shows that Dynamat Extreme is more expensive, heavier, and only deadens sound better than Brown Bread at its optimal temperature (~68F). It is easier to install, thinner, and leaves no odor.

Brown Bread on the other hand, is cheaper, lighter, and deadens sound well throughout a range of temperatures. It is, however, thicker, more difficult to install, and leaves a tar-like odor. I've also heard reports of the adhesive leaving a residue, and even loosening at higher temperatures.

The B-Quiet Extreme is obviously much cheaper, but also doesn't even compare to the other two in sound deadening ability.

The data would lead me to believe that the Brown Bread product is overall a better value, however, the odor and possible adhesion problems leave me a bit hesitant, so unfortunately I'm still undecided. What do you guys think about this?

What I've also come to realize is that all of these products are designed for vibration damping rather than sound damping. It seems to me that, although important, vibration damping is really only necessary in areas in the car that are subject to high vibration (such as behind speakers). Wouldn't it make more sense to cover the entire car with a sound deadening layer (like LComp,VComp, or Dynaliner) if my goal is better car audio sound and less outside noise?

[NC_VX]

I am with KPASKE on that one. The optimal performance is for sound, not vibration, so maybe a little Dynomat Extreme in the door and rear door, where the subwoofer is and then Dynoliner in the rest of the car...

Does that sound right to others?

[Hotsauce]

Vibration is sound, just a lower frequency.

Some of you have seen my roof flex, and bounce keys, coins, and cups of water off when I crank the sound up.

Sound deadening, whatever brand, makes a HUGE difference in the clarity of the bass, and add to the overall blackness of background noise.

John C.

[kpaske]

Yeah, I wound up using Brown Bread all the way around, in addition to a layer of VComp in the rear and HLiner under the hood. The difference is incredible. The coolest thing is I can crank it way up inside and you can barely hear it outside until you open a door. You can still hear the highs a bit if it's really blaring, but there is zero vibration to spread those lows anywhere except where they're supposed to be.

[MZ-N10]

so how much did u acutally need to cover the whole car?
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[kpaske]

I used:
(1) 70 Foot Roll + (1) 35 Foot Roll of Brown Bread
(1) 35 Foot Roll of VComp
(1) Large HLiner

In retrospect, I'm not sure how much effect the VComp really has on the overall sound deadening because immediately after the install I didn't notice much of a difference in the rumbling coming from my PV muffler (which it was mostly intended to cure). However, the 105 ft of Brown Bread was just barely enough to do a single coat on nearly every interior surface. Two 70 foot rolls would have been preferable to get more of the inner door and sidewall surfaces, though I don't know if it would make a huge difference. My VX is pretty well dampened ASIS.

[On Your Left]

kpaske,

How long did the install take you? And what diffulties did you encounter? Also, what about the odor? Did it go away? Any regrest on the brand you chose?

JT

[kpaske]

Starting early one Saturday morning, with my wife's help, I was able to disassemble, wipe down, apply all of the Brown Bread and the Hliner, and partly reassemble before nightfall. We probably could have completed the project if we started at daybreak, but I had some wiring and such that I wanted to do the following day anyway.

I haven't had any issues with odors at all. Since I did it in the summer, it was already warm, so I didn't need to apply heat and didn't have any problems with adhesion or spreading it into the corners and tight spots. The whole project went quite smoothly. I do recommend poking all the screw holes through as you're laying out the material, as they are very difficult to find once all the surfaces are covered.

Definately no regrets using Brown Bread. The stuff is great, and provides an excellent audio environment. There are certainly cheaper options out there, but I think it gives you the best value for your dollar if you're looking for a high quality product.