Leaderboard

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.

I usually think of weatherstripping as self adhesive foam. Do you mean flashing tape? Some is asphalt, some is butyl and it all has a thin foil layer or no foil layer at all. As Impious stated, an adhesive designed for waterproofing is not going to be ideal for vibration damping. Even though the butyl blends are less likely to fall off, they don't perform any better than asphalt. It's really important to understand that "butyl" is just the base component of these adhesives. It is essentially a synthetic rubber. By itself, it would be a terrible vibration damper. Like rubber, it is almost purely elastic and will simply return any energy it receives. That's why claims of "highest butyl content" and highest rubber content" are silly. That's like claiming your mathematical formula is superior because it use more numbers or your song is better because it uses more notes. Viscoelasticity is the key to all of this. If anybody is really interested, PM me with a shipping address and I'll send you a sample of a viscoelastic adhesive. There's nothing better than stretching and releasing a viscoelastic material to understand what is going on. Stretch and release it repeatedly and it starts to get warm. Light bulb moment. I think you'll find that people using flashing tape and reporting great results haven't used a true vibration damper before. With no basis for comparison, a barely noticeable change can be perceived as "great", especially if you've just spent 2 days on the project and really want to believe it was worth the effort. Impious made an extremely important point for anybody who believes it doesn't matter what you use since you are just "mass loading" - quadruple the mass to lower resonant frequency one octave. That for EACH octave - the second will require 16 times the original mass, and so on.

Adding mass lowers resonant frequency, stiffening a panel raises the resonant frequency. So if you add some mass and lower the Fs a little, but at the same time stiffen the panel some which raises the Fs a little, then the net result is virtually no change in Fs If you add mass without stiffening, then Fs will decrease. It takes a 4x increase in mass to decrease Fs by one octave. If you stiffen without adding mass, then Fs increases. As for results with weather stripping......Don has mentioned over the years as well as in this thread that the viscoelastic properties of the adhesive layer are going determine it's effectiveness as a vibration damper (in addition to some other things). My guess would be that a material designed for the construction industry is probably not going to utilize a compound ideally suited to vibration damping, and that's before we even discuss differences in the other important factors to CLD performance. But Don could go into much more detail. Great thread Don!! Sound deadening is one of the areas in this hobby that needs a lot more accurate information being presented and a lot less voodoo and mysticism about what works and why. Glad it was you who stepped up to fill that role extremely well for the past few years.

We got the hatch cover fans installed and it turned out pretty good. Here are the pics... By sefugi at 2010-09-30 By sefugi at 2010-09-30 A few shots without the flash to give idea of the night apperance... By sefugi at 2010-09-30 By sefugi at 2010-09-30 Closeup shot... By sefugi at 2010-09-30 Through the back glass... By sefugi at 2010-09-30

We are proud to announce the 2010 ICON as many of you have already seen. These are now available in the SSA store. We are running FREE shipping on them for the month of October to celebrate their long awaited arrival. We have a handful of these in stock and ready to ship! NO WAITING FOR BUILD TIME! 2010 Upgrades include * Lowered Price! * Sandwiched Leads * Upgraded Suspension * Full style dust cap ** Aluminum Coil ($25 Option), for added thermal ability and power handling. Free shipping for all of October 2010! 12" $259 (+$25 for Aluminum Coil), Free shipping for the month of October! http://www.soundsolutionsaudio.com/store/products/12%22-SSA-ICON-12D1%7B47%7DD2.html 15" $279 (+$25 for Aluminum Coil), Free shipping for the month of October! http://www.soundsolutionsaudio.com/store/products/15%22-SSA-ICON-15D1%7B47%7DD2.html **Note, the 10" Version is on hold until our new dustcaps come in, you can still get them with the new options, they just will not have the new flat dust caps, sorry for the inconvenience!

15" ICON

time for more photo's! 12" ICON

http://www.soundsolutionsaudio.com/forum/topic/44340-interest-in-a-group-buy-on-a-zed-built-boss-audio-rev-665/page__pid__699144#entry699144

For those of you who don't know me, i'm Mark's Friend/roommate and I decided to make my own entry into this since I bought some bravox last week. Hope you enjoy... Here's my entry.

Am I going to finals? Hell no. I am not interested in driving half way across the country to possibly win a plastic trophy. I live too far away. I don't need to see the truck in person to understand your choices. Most are self explanatory...except for the amp change of course. Also, don't take my questions wrong. You seem to be getting agitated that I was asking your reasons for switching amps. I was just curious. As I stated before, it is surprising that there is another amp out there from LP that can meet, or surpass, the 2.2HV in SQ and most people don't know it. I surely didn't. I think if more people knew, the search for the 2.2HV wouldn't be as intense and most would be searching for the DPS500. You do know that Ray (TIPS) does modifications to just about all Linear amps. Are you talking about stock amps or modified amps ??? All of our amps has been modified. (no secrets) all the info can be found on www.linearpower.com ... If you know Ray as well as we do ... anything is possible.