# Second Skin SPL Tiles - First Impressions



## Lnh (Mar 24, 2009)

While at the Second Skin show/competition last Saturday I met Ant and he hooked me up with some of his new SPL Tiles to do my roof with. I got 25 from him and ended up with 4 tiles and some scraps left over.

Quick pics first. Here's my roof with one Tile on and the one of the two chintzy stock strips still attached (the other fell off as soon as I pulled the headliner):









Whole roof covered:



























Now that the shiny part is out of the way  here goes. Basically, I love them. I decided to only do one layer to see how well they perform, and there was a distinctly audible difference from stock to these...especially on my favorite beats song that hits just the right note to resonate the roof of my car quite well (unfortunately). After these were on, said resonance was no more 

They are easy to manipulate, and because of the smaller size they're extremely easy to place and install. The adhesive is great...I had to reposition one of the trimmed tiles 3 times and it came off without any issues, but once it was rolled down I couldn't get it to budge. I strongly suggest using scissors to trim the tiles if you need to...a razor knife doesn't like to go through such thick foil very easily.


Long story short, they're awesome. These Tiles have caused me to switch from one of the 'other' brands of sound deadener products. The rest of my trouble spots I have yet to treat will have Second Skin products on them without a doubt. I really wish I had a meter to test the difference before and after, but oh well.

According to the site, these Tiles are supposed to start shipping next week. I know I'm going to be picking up some more for sure 


Ant, keep making awesome products :thumbsup:


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## Sr SQ (Dec 8, 2006)

I gotta agree these tiles are sic
I used them on my front doors and the difference between them and the rear ( 1 layer of BXT) is incredible. I think Ant said it would take 4 layers of reg dampener to get the same result as the tiles do.


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## kickinaudio (May 15, 2009)

These things rock. Very impressive.


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## unpredictableacts (Aug 16, 2006)

So much for 25% coverage.


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## chad (Jun 30, 2005)

no **** man, why not just buy sheeting?


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## 12vTools (Jan 15, 2009)

I dont think i would stop until i had 300% coverage =)
great stuff there!


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## chad (Jun 30, 2005)

^^^brainz^^^

zombie material right there


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## Megalomaniac (Feb 12, 2007)

You better polish that foil, so it has plenty of cooling


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## Lnh (Mar 24, 2009)

chad said:


> no **** man, why not just buy sheeting?


Cause I got them for an amazing deal lol. Plus these are better at deadening than any sheeting that I've used before.




unpredictableacts said:


> So much for 25% coverage.


I don't think I've ever done the whole 25% coverage thing...it may work sufficiently, but why not cover the whole thing if you've got the material and you're already in there? You're gonna get better results this way.


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## Rudeboy (Oct 16, 2005)

Lnhiv said:


> I don't think I've ever done the whole 25% coverage thing...it may work sufficiently, but why not cover the whole thing if you've got the material and you're already in there? *You're gonna get better results this way.*


That's not correct. An argument can be made that 50% coverage will outperform 25% coverage in extreme conditions, but the idea that 100% coverage is even better is based on two misconceptions:

That constrained layer dampers stiffen panels to a useful degree
That constrained layer dampers work the same way extensional dampers work.

Vibration dampers are commonly used to address two problems. The first is panel resonance - vehicle components vibrating sympathetically with sound coming from inside or outside the vehicle. Sometimes a panel can be set in motion by mechanical means - The foot bone connected to the leg bone, etc. 

When treating panel resonance we don't really care what has excited the panel, applying a constrained layer damper to the resonant areas of the panel converts the vibration into heat. This isn't to say that treating the source won't be more effective - it will - but let's assume that we have done all we can and still have resonance. Vibration deforms the adhesive and strains between the adhesive and the substrate and the adhesive and the constraining layer do the work. Applying a constrained layer damper to the non-resonant areas of the panel does nothing but make it shiny. Constrained layer dampers are designed to yield when they encounter vibration so stiffening isn't a factor.

The second problem is panel deformation or "flex". This is an issue for the extreme SPL folks. The panels change shape in response to changing pressure levels. Think of this like blowing up a balloon versus blowing air into a glass bottle. The balloon wall yields as the internal air volume increases. The rigid walls of the bottle resist the increasing pressure within. If you are concerned with the numbers on a meter, you don't want the vehicle panels to yield. Reinforcing the panels is the solution. If you are a competitor, you have to do this within the rules of the organization within which you compete. If you just like things really loud and also want to limit panel resonance you should be using an extensional damper like a liquid or glued on material.

Extensional dampers work by resisting panel deformation. They effectively stiffen the panel and also convert vibration to heat as they fight to hold the panel to its resting shape. Since stiffening the panel is the goal, it can help to cover more of the panel. Remember, stiffening also raises the resonant frequency which may or may not be an issue but it will come into play whether you use mechanical bracing or an extensional damper.

It's as simple as this:
Those who want to control noise and get rid of panel resonance should use a reasonable amount of a constrained layer damper and a barrier, possibly with supplemental absorbent materials.

If you just want to get rid of panel resonance, use a reasonable amount of constrained layer damper.

If you want all out SPL, brace the panels and enjoy the racket. Don't use any vibration damper since they will reduce the energy available to meter by design.

If you want extreme SPL, want to limit resonance and can live with the resulting higher resonant frequency use an extensional damper. Alternatively, brace the panels and use a reasonable amount of constrained layer damper.

This doesn't say anything about the product used by the OP, just that the reasoning behind his chosen application and subsequent defense of it is faulty. There's no real negative consequence other than making sheet metal that doesn't need to be made inaccessible inaccessible. That and a waste of materials. Not making something worse doesn't mean you made it better.


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## dkh (Apr 2, 2008)

I like the idea that mass loading a surface reduces its ability to resonate and if 100% coverage adds more mass than 25% there must be an audible difference.


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## chad (Jun 30, 2005)

dkh said:


> I like the idea that mass loading a surface reduces its ability to resonate and if 100% coverage adds more mass than 25% there must be an audible difference.


in THEORY you can ccreate a whole new resonance, in fact if you make the tiles look prety and equally spaced you can create, AGAIN, modal issues. 

Random is bestest


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## Melodic Acoustic (Oct 10, 2005)

hmmm very interest topic. listening


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## chad (Jun 30, 2005)

think harmonics on a guitar string, to get a harmonic you don't fret the string out but just touch it to set up a mode.


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## Rudeboy (Oct 16, 2005)

dkh said:


> I like the idea that mass loading a surface reduces its ability to resonate and if 100% coverage adds more mass than 25% there must be an audible difference.


Adding mass lowers the resonant frequency much more than it decreases the amplitude of the resonance. Even so, you have to add so much mass to a panel to lower the resonant frequency out of the audible range that it is almost an absurd goal when there are so many more efficient ways to go about it. 

Vehicle panels are fixed at the edges. The closer you get to the fixed edges the less the panel moves and we still end up with diminishing returns. If you want a panel to stop moving, brace it with something rigid. 

"Mass loading" as a vibration damping technique is really just a rationalization for using asphalt or thin foil butyls - materials with almost no vibration damping capacity. Outside of very specific conditions where one part needs to have its resonant frequency shifted away from a single and unavoidable exciting frequency, you won't find this concept cited anywhere but in the aftermarket automotive realm. For our purposes we need much more generalized solutions.


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## Lnh (Mar 24, 2009)

This has become quite interesting. Once question for you: what would an extensional damper be then?

I hope this discussion keeps going so that if nothing else it will help in material selection for the rest of my car.


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## Rudeboy (Oct 16, 2005)

Lnhiv said:


> This has become quite interesting. Once question for you: what would an extensional damper be then?
> 
> I hope this discussion keeps going so that if nothing else it will help in material selection for the rest of my car.


Extensional dampers are the liquid applied products and the vinyls with adhesive (not the barrier products). There are other specialized products that are a lot harder for us to get our hands on.


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