I used a ton of Dynamat Xtreme and with my system on even half volume my dash rattles, my hatch rattles, etc. I'm running 2 12W0s in the trunk so I expected the hatch to move but not the whole dash...

 

I used 2 bulk boxes of Dynamat Xtreme when I did my install. Less rattles, sub sounds way better, but the engine sound isn't nearly as noticeable now... Oh well, another good excuse to upgrade the exhaust.

@Disco
I like your "mangled hands" pic. My hands looked exactly like that when I was done. Definately a very painful install.

 

MIAPLAYA:

What part of your car did you dynomat? Is there a way to dyno mat the dash? Let me know if you've solved your problem.

 

Hey guys though I would chime in on this topic real fast.

Here is the scoop from someone that manufactures both mats and liquids.

When applied in equal thicknesses to constrain layer dampers (vibration mats with foil), liquid based elastomers are better at damping vibration and air borne sound over a broader range of frequencies than mats, they are also cheaper and light, in is most cases look better.
The Foil does reflect radiant heat, but most liquids will contain nanoscopic ceramic spheres which reflect heat as well. Liquids are better in ever possible way.

Products like Fatmat, edead, Rammat, brown bread, etc are bituminous based. Meaning they are asphalt, or modified asphalt. the reason they are so cheap is that asphalt is very inexpensive to product, but as a result the heat tolerance is much lower than required. the highest you can get with bitumen is 230 degrees. We used to make an asphalt product, and even though we used the best raw materials available, and had top notch chemist working on the formula, the best we could achieve was 230 degrees before sag, slide melt and fail.

This is why we no use military grade butyl for our constraint layer mats. With heat tolerance of 450 degrees.

The heat tolerance of a mat is important not only because it can possible melt off in a hot day, or hot part of the car, but also because constrain layer dampers use elastomeric compounds (asphalt, butyl etc) as the energy converting base. this is what transfers the vibrations from movement to heat.
As elastomers heat up, they start to break physical bonds within the molecular chains and will loosen up (just like warm bubble gum and gummy bears will soften in heat)
As they heat up and loosen they stop damping vibrations and sound as well. the high the heat tolerance of the mat, the more it will dampen sound at higher temperatures, so where as dynamat extreme is at 300 degrees and product x is at 500 degrees, product x will do a better job in high heat situations.

usually you wont get up to 500 degrees in a car, but the metal will hit 250 pretty fast in the summer (higher is the car is dark in color) or in high heat areas like the hood, firewall, and tranny tunnel.

Part of the heat tolerance has to do with the thickness of the foil as well. Asphalt dampers have 1 mil foil heat shields. Most butyl mat are 3 to 4 mils thick. this absorb heat away from the butyl keeping it cooler. The foil can also be used to reflect radiant heat when used on the fire wall, or hood.

All the product listed work well , and have their applications, especially for budget minded people., but in some cases, 2 layers of asphalt are still not even equal to 1 layer of Butyl depending on the application and specific product.

It is true that you get what you pay for with dampers, just because they look similar does not mean they are.
After all, a 350z might look identical to a Huyandi Tiburan to someone who has never seen a car before...

Anyways, if anyone has any questions they can email me
service@secondskinaudio.com
or call me at the number listed on the web site
I am always happy to help regardless of what product you use...

ANT

 

Also, something about airborne sound; exhaust, engine noise, road noise etc..
Mats are not designed to reduce sound; they are designed to reduce structure borne vibrations. Some airborne sound will be reduced at various frequencies but not an extreme amount unless you apply multiple layers. Airborne sound waves will still penetrate the damper. The more efficient way to dampen sound is to use 1 or 2 layer of mat, followed by a barrier and absorber combination.
Usually a vinyl or lead based barrier at 1 lb. per sq foot will do the trick. The barrier needs to be elevated off of the damper to allow the airborne sound waves to slow down before hitting the barrier (sound waves travel faster an more aggressively through solid than through air, so elevating the barrier and allowing some air between the barrier and damper will help reduce the noise)
Since you can levitate the barrier we use open cell acoustic foam as a decoupler, this helps slow the sound down, allows it to hit the barrier and reflect off of it.
If the barrier were just laying on top of the damper, a lot of the sound waves would pass right through it (not all, but some), and would be acting as amass loading damper rather than sound barrier.
Doing a damper, barrier, absorber combination is much cheaper and lighter than loading up on multiple layers of mats.

Of course, the most efficient want to do it all is to skip the mats, skip the barriers, and go to the liquid dampers. 2-3 mm thickness of liquid based elastomers will do a better job than 2 layers of mats, and a barrier absorber combo.
Liquids skin over and dry to the touch in about 20 minutes and are cured in 24 hours. Most have no odor and are non toxic.

Here are the most efficient ways to reduce various noises:

ROAD NOISE:
1. Wheel wells. Use liquid damper on all 4 wheel wells, underside
2. Wheel wells. Use liquid damper on all 4 wheel wells, top side
3. Quarter panels. Treat all quarter panels with liquid or mat
4. Doors. treat inner and outer skin, sealer all non functional holes
5. Floor pan. treat underbody from firewall to trunk/hatch
6. Floor pan. treat interior floor up to fire wall

ENGINE NOISE:
1. Firewall. treat the exterior firewall with liquid
2. Floor. Treat underbody and interior floor with liquid
3. Firewall. treat interior firewall with liquid
4. Hood. treat hood with liquid
5. Ceiling. Treat ceiling with liquid

Exhaust
1. Floor. Treat interior floor hatch area with 2 layers liquid
2. Floor. Treat undercoating of hatch floor with liquid
3. Floor. Add barrier absorber to hatch to reduce low level frequencies


That’s all for now. Hope it helps

ANT

 

i just got done putting 1 coat of second Skin spectrum (liquid stuff) its very easy to put on. If it gets some were i dont want it to be it seems to just wipe up with ease. Ill be putting between 3-5 total coats on..... Ill let everyone know my results

 

Make sure the final thickness is at least 1 mm.
2mm is better but at least 1mm thick..
ANT

 

To anyone who has applied any type of liquid sound dampener to their wheel wells or hood, could you please tell me how you did it? Or at least, how difficult or easy it was? Also, maybe someone could post some pics. Is it just as easy as removing the front wheels and spraying? I'm tired of all the road/tire noise and especially all of the rattles t/o my car.

 

I did it the cheap way...by jacking up the car in the garage, removing the wheels, and carefully taking out every plastic panel in the well and the mud guards. Then i used masking tape and a lot of newspaper to mask off everything. I sprayed Dupli-color Professional series rebberized undercoat in the well and on the back side of the plastic components. About 4 layers (3 cans) were used and I really like the improvement. it looks nice, I no longer hear rocks pinging and the tire noise has decreased quite a bit.

 

I w0ould try to stay away from the rubberized undercoating. it is not exactly an elastomeric damper. it will help some but not that much. If you applied the same amount of liquid damper as you did the Rubberized undercoating, you would have noticed a bigger difference in road noise.

ANT

 

i'm trying to dynamat my car.i'm gonna use the liquid stuff for my wheel wells, how hard is it to get to the wheel wells?and should i put the liquid fatmat on my wheel well plastics too?

 

I ended up using Spectrum II on most of the car including wheel wells. It is great stuff anf goes on like thick paint. Just use a brush (natural fiber seems to work better as they don't frey like polyester). The liquid I used wouldn't stick very well to plastic and the rep recommended not doing it. But I did put some on the backside of the plastic well panels because they are such a large part of the front. I used a rubberized primer first, let it dry, and then brushed on a few coats of Spectrum. I then cutout a piece of Vibramat and affixed it to the backside as well.

Liquid works well, better IMO than the Dynamat Extreme I used. It may not reduce as much vibration but does a better job on tire noise. However, I found that no mat or liquid solution met my needs so I ended up using a lot of acoustic foam as well.

 

The wheel wells are accessed after you remove the wheels, I did one at a time. Wrap the brakes with newpaper to protect against drips. I also covered the plastic connectors and threaded bolts with masking tape. Liquid Fatmat cleans up quickly with water before it dries.

I did coat the plastic liners inside the front wells, but left the air holes open for air flow. I used a (new) cheap 3" paint brush for each coat, they get gunked up when the stuff dries. Concentrate on the rear wells, that's where most of the noise comes from, and the more coats the better.