Rudeboy

Do the rear seat backs fold down? If so, is it worse with them down?

Stock exhaust?

Close to half the vibration damping/noise mitigation threads on other forums are debates about using asphalt based materials as a vibration damper. I’ve spent way too much time during the last 5 years typing and re-typing responses to these questions. Let’s keep it in one place to reduce litter and redundancy. This topic was my introduction to aftermarket “sound deadening”. I had a noisy car, wanted to quiet it down and started to do research. This was 2005. Several respected “authorities” were vocal advocates for asphalt. Part of this came from the belief that products like Dynamat Xtreme were part of a conspiracy to fleece consumers. Part of it was the often repeated “fact” that roofing materials and vibration dampers sold specifically for aftermarket automotive use were exactly the same thing. One cost pennies per ft² and the other dollars so it was worth investigating. Some of you may remember that Sound Deadener Showdown used to be a testing and review site. Since I wasn’t able to find any conclusive answers on the forums, I decided to buy small quantities of every product I could. Two things were immediately apparent: Nobody had ever had their hands on all of these products at the same time or they would have seen the obvious differences. The people claiming that Dynamat Xtreme and roofing materials were exactly the same thing didn’t know what they were talking about. I discovered a few other things very quickly. Many sellers were making outrageous claims. Some were wildly overstating obvious physical characteristics like thickness and mass/area. Others were either claiming outright that their asphalt products were butyl or were using intentionally deceptive descriptions like “rubberized compound” to describe their adhesive layer. Nobody seemed to be drawing the right conclusion from sellers’ attempts to hide the fact that they were selling asphalt. For several years the argument was about durability. Asphalt had an unhappy tendency to melt or fall off. At the time, there were no reports of butyl adhesive failure – that had to wait a few years until one seller decided to re-purpose some low quality butyl roofing material. I spent a lot of time trying to figure out why this was happening. All of these materials are asphalt with some sort of rubber added to increase heat tolerance. The generally accepted melting point for these compounds is 180°F. That seemed high enough for use in a vehicle, so what was going on? Our perception of the heat these products are subjected to was wrong. We thought in terms of air temperature inside the vehicle, maybe 140°F-150°F? It turns out things are very different at the sheet metal. Park a car in the sun during the summer, south of the Mason-Dixon line and you can easily get to 180°F+. That explains immediate failures in hot climates. An insidious part of this problem is that many failures were reported during the second or third summer, many in fairly mild regions. The explanation was pretty simple. The rubber added to asphalt deteriorates over time when exposed to temperatures much lower than those required to melt the fresh material. As the rubber deteriorates, the melting temperature drops. Suddenly it doesn’t take much heat anymore. The durability question has been answered to my satisfaction. Many high profile asphalt devotees, including some who went to almost insane extremes to install the material “properly” have had their installations fail over the years. A few of the brave ones have come forward and made their results public. The pennies vs. dollars argument still nags. What if you plan to junk your vehicle after a few years (worse, plan to trade it in and don’t care what problem you are passing on)? Is asphalt a reasonable choice when durability isn’t a factor? Nope. There are two main reasons people believe they can substitute asphalt roofing materials for CLDs: They look alike – shiny on one side, black and gooey on the other. They don’t understand how a constrained layer vibration damper works. See: Caddy Shack, swimming pool scene for all you need to know about point 1. Point 2 needs more consideration. I used to believe that vibration dampers work by adding mass to a panel and lowering its resonant frequency below the audible range. This is completely wrong. They work through a fairly complex sequence of events that occur in the adhesive layer and between the adhesive layer and the constraining layer and substrate. I won’t go into the details here, please see: Vibration Damping By Ahid D. Nashif, David I. G. Jones, John Phillips Henderson The important point is that everything depends on the material property viscoelasticity. Basically this describes something that can be deformed and will then return to its original shape more slowly than it was deformed. The strains created during these events account for the conversion of vibration to heat that we’ve all heard about. Butyl adhesives formulated for vibration damping are viscoelastic. Asphalt isn’t – it doesn’t need to be to seal a roof. Asphalt adds mass to a panel. It may stiffen the panel, but since stiffening raises resonant frequency, the two mechanisms are offsetting and reduce effectiveness even further. Those who claim to have used it and had good results aren’t giving you the full picture. These claims can be better stated as: I used asphalt. It was better than nothing. I haven’t used a proper purpose designed vibration damper so I have no basis for comparison. It hasn’t failed yet. Sometimes the endorsement is explicitly stated: I used asphalt and it hasn’t fallen off. Not falling off is a pathetically low standard of performance. Testing I’ve done has convinced me that it takes between 6 and 10 times as much asphalt to achieve something approaching the same result you will get with a real vibration damper. This puts the pennies/dollars question on its head. Add the durability concerns and the huge amount of extra work required and the answer is pretty obvious. I’m sure some will want to argue the points I’ve made here. If that’s you, please stay away from “I used it and it worked for me”. That’s how we got into trouble in the first place and doesn’t make any more sense than concluding that cigarettes are good for you because your grandfather smoked a pack a day and lived to be 90. If you want to go there, please show us some evidence.

Couldn't agree more. Even at 25% coverage with CLD we are just "slapping it on". That's the best we can do working on one vehicle at a time. It can't be said enough that for all of the attention paid to vibration dampers in the aftermarket, they are a small part of any noise reduction solution. Blocking airborne sound is where it's at and barriers are the key tool there. When I'm treating a vehicle, I look at applying vibration damper as a warm up for the real work to come. Absorbers are the icing on the cake and can make a very nice reduction in the high middle to high frequency range. All comes down to the right tool for the job.

Yes, I ripped it all out, added a little bit back to the bare sheet metal areas and covered the entire thing with CCF and MLV. Now that I think about it, Aaron helped me pull the vibration damper out It was all part of the process of learning how to treat a vehicle properly. Spare tire wells are probably the most over treated vehicle areas. People pull the spare out, tap on the sheet metal and hear how flimsy it is and start adding layers, not realizing that the spare itself is part of the NVH system.

How much vibration damper did you use? Did you cover the trunk vents? I had this happen once when I used way too much vibration damper during my first attempt at quieting a Civic. Put down multiple layers in the trunk. This changed the geometry and mass of the panels that make up trunk floor, moving its resonant frequency into a problematic range. I actually managed to create exhaust drone in a stock Honda Civic

You really need to identify the source of the rattle before you can eliminate it. If it is the trim panel rattling against the inner skin, the weather stripping you linked should be fine. You can be pretty sure that's the problem if you can stop the rattle by pressing your hand against the trim panel. More often than not, it's something inside the door rattling - actuator rods, window track, etc. The foam isn't likely to be useful in any of those scenarios. Key point is: identify the source of the rattle before you try to fix it.

Oh nice, you're about an hour up the road from me, I'm in 21122 (Pasadena). You're a lot closer to the water than I am. Make out alright in the storm?

There's a lot that is already sort of in place. Still working like mad. Here's what I've got for doors so far: http://sounddeadener...le-areas/doors/ I'm trying to get things flowing so that a person can come to the site knowing nothing about the topic and leave with an understanding of what needs to be done and how much material he or she will need to get it done. Don,What part of MD are you in? (Assuming you are still active here!) Thanks. - Dave Manchester, 21102

ED were trailblazers At least they were the first I ever saw exploiting the "everybody but us are idiots" teenage mindset. Distract from the low cost/poor quality problem by defining it as high quality priced for our friends. I'm not saying everything they sold was garbage, but I was often struck by how often they were the first system but not the second. I think it was more confusing a few years ago because most still expected the truth to out on the Internet. We all still had to learn how the message could be corrupted in an "open" medium by the ethically challenged. When I first started testing vibration dampers, ED supporters were outraged that I dared to point out that the basic specs the company presented for their products were way off. I actually got death threats

Sorry guys. I'm actaully in MD, not PA. If you'll PM me your e-mail addresses I can track down your message. Sorry for the delays.

The critical characteristic of the adhesive is that it be viscoelstic. If you make a ball out of adhesive, stretch it and let it go, it should return to pretty close to its original shape - it shouldn't just stretch out and stay like taffy. If it isn't viscoelastic it woun't work, whether it sticks or not. The waythe adhesive has stretched out in those photos makes it look like that batch of adhesive may be lacking the elastic part of the equation.

Part of the problem is that people love to believe that everybody in business is adding huge markups and that if only a decent person would come along, we'd all have great products for very little money. Several businesses in this sector (some listed above ) have thrived on the premise that everybody else is an idiot but because you are "in the know", they'll sell you the best products at "insider" prices. Ironically it's often the lowest priced goods that carry the highest markup. Definitely doesn't make them a good value.

It's actually worse (and funnier) than that. It started with the soda can tests which proclaimed SDS the winner! He actually left that video on Youtube for something like a year. I was still getting queries up until a few moths ago from people wh saw the video. While he was gathering samples for the soda can testing, he got hooked up wth AudioWrap someow and was spamming their product. Soon after that he decided to launch his own product and started spaming forums again. Somebody from one of these forums e-mailed me to ask if I knew who cthedinger was. He told me the forum members had backed him into a corner by asking him to explain how vibration dampers work. About two minutes later I get an e-mail that starts: "Hey Don. I was just thinking about things. Can you explain to me how vibration dampers work - strictly for my own education"? No joke.

While flattery is nice, it does not pay the bills. So if your are being copied and they are selling to what should be your customers, it starts to take a negative roll. Thus internet wars end up starting lol. It's especially negative when the imitator says the object of his imitation is ripping people off by overcharging for crap, while his product is "better than Dynamat" (hypothetically :

"Manufacturer" may be a stretch

Let's hear it for the free exchange of information

The secret to removing a low quality butyl adhesive is by using a better quality butyl adheisve to dab at it and pull it off. Aaron and I did this on a project and it works well until the better stuff gets overloaded and you have to throw it away. I've got some damaged Extruded Butyl Rope that would be perfect for this if you don't have anything else to use. PM me with an address and I'll send you some.

He's only 200 miles from here - you're the one who's across the country It really isn't impossible to diagnose the problem without a lot more information, maybe not without actually seeing the dor. OTOH, it should be pretty easy to diagnose for you. I'd start by creating the rattle and pressing my hands against the trim panel. If that solves the problem we'll have a pretty good starting point. If not, press your hands against the outer door skin. If that doesn't solve it, you'll have to remove the trim panel and poke around. It's possible to just add some vibration damper or other products and hope to solve the problem but it's much better to actually know what you're dealing with before you treat it.

MLV is really for blocking sound. All of these products are meant for noise reduction or sound quality installations. Not saying a vehicle can't be multi-purpose but if you are generating enough pressure to distort panels you pretty much have to accept the vehicle being disposable. Bracing the panels is the best approach, so gluing MDF to the sheet metal is no unreasonable, I guess. Just realize that almost anything you can do to make a vehicle able to withstand the abuse will preclude any future body work. short of sheet metal replacement.

Sorry about that. Things have been crazy. What's your e-mail address? I'll track them down.

Those don't have enough density to block sound. They aren't thick enough to absorb anything much either. I understand what you're trying to do I've done it myself. The standard treatment for a door, especially one with spekers in it is to apply a barrier to the inner door skin. This blocks noise from the outside and acoustically isolates the front and rear waves fro the speaker, improving its performance. You are less concerned wiith performance and quiet inside the vehicle than you are with reducing the sound heard outside the vehicle. To accomplish this you want to line the outer door skin with a barrier material. I cared about performance, interior quiet and exterior quiet so I lined both the inner skin and outer skin. You'd reduce the sound outside the vehicle further by treating the entire interior, but the barrier on the outer door skin should make a noticeable difference.

I'm going to do the whole inside of my jeep with cld, mlv, and ccf. The top might block a very small amount of noise compared to the doors or wheel wells, but everything is getting covered. I know its a waste of money to do 100% coverage with cld, but to much won't hurt anything. After the entire inside is covered with those 3 materials I should have a pretty quiet ride. I'll send you another email, I would still like to get some mlv and ccf for the floor and doors. Still not trying to be difficult, but a couple of points to consider: 1) I'd be reluctant to add weight to the highest poinnt in a Jeep without a really comprelling reason to do it. 2) Unless minimizing the sound from inside that can be heard outside, the adding a barrier to the roof isn't going to accomplish much, if anything.A barrier blocks sound traveling through the air. There are very few noise sources directly overhead. For sources that are not directly overhead, there's no point in building a barrier above the glass line that blocks better than the glass itself. 3) Vibration damper works beause the adhesive is viscoelastic. The warmer it gets the more it slides to the viscous side. When the deformation is slow and steady, it performs more like a liquid than it does rubber. Unless something will be under the barrier to hold it in place, it will eventually come off the roof with the foil. If the top is dark and you live where there is sun it coould happen rather quickly.

Sorry I missed your e-mail. Very neat job on the top. Not trying to be a dick, but what is a barrier going to do for you on the roof?

That really is the critical question. I've seen mass backed carpets that had a backing that was .25 lb/ft² or less. If you'll be putting 1 lb/ft² MLV under that, it won't make an audible difference. The other issue is that while the mass backing may not have a lot of sound blocking capacity it can be the difference between a premium product and a really flimsy piece of crap. It can also be the only thing that gives the carpet shape. Sometimes mass backing is an effective noise control tool. Sometimes it's like the heat reduction claims made for foil faced vibration dampers - it's not technically a lie, so let's claim it as a feature