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Discussion Starter #1
driving today, heard a loud crack sound, apparently I hit a small pothole or a small rock hit my windshield or the heat inside the car vs the cold outside took a tiny crack in my windshield and spread it pretty much all the way across.

Now, I've heard lots of people say things like a more expensive windshield is resistant to cracking/scratches or better for heat insulation, etc. But does anyone have experience with different types of windshields being better/worse for sound insulation? "Better glass" seems to be a common theme for luxury cars to talk about when they say their cars are nice and quiet, but I'm not sure how much truth there is to that, or if it's a result of better sealant around the windows, or thicker side windows.

So, any knowledge people has about glass would be appreciated!
 

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My TL came with acoustiglass and one time it was replaced with a "regular" windshield and roadnoise was definitely increased. I made them replace it with a factory windshield and the noise was decreased. The problem is I haven't found one for under $550.
 

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Discussion Starter #3
Hmm, $550 for the cost of the "Acoustiglass" windshield? How much does a regular one cost for comparison?
 

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Hmm, $550 for the cost of the "Acoustiglass" windshield? How much does a regular one cost for comparison?
It was through insurance but for my car I think it was around $180 installed. Well worth it if you have a nice system. I wondered why road noise would be reduced more than wind noise and I was told the windshield acts as a big "speaker" and amplifies vibrations in the chassis. The gel in the middle dampens it.

I realized the car had the wrong windshield because of the additional noise. The early TLs said "Honda" on the glass parts so there was no obvious give away, I searched for the source of the extra noise after replacement and finally found that it came with this special glass.

My friend's AMG CL65 Mercedes has double paned side windows as well. Now that my TL is thoroughly sound deadened I understand why Mercedes did that. With very little noise coming through the body panels, the noise transmitted through the side glass is obvious now. Sometimes it sounds like I have a window down with the rest of the car being quiet.
 

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Discussion Starter #5
So, how well does that acoustiglass work for all other purposes? (resistance to scratches, holding in heat, etc)?
 

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So, how well does that acoustiglass work for all other purposes? (resistance to scratches, holding in heat, etc)?
I don't know a whole lot about the subject so hopefully someone more knowledgeable will come along. I believe it's regular glass but with a gel or even gas layer in the center to dampen and isolate noise. Resistance to scratching is like any other windshield however I would *guess* each layer might be thinner because it seems easier to crack. Maybe it's just my bad luck. But again, that's just a guess.
 

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Discussion Starter #7
Yah, I just did an internet search and apparently some (for Odysseys at least) were defective it seems.
 

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I've been looking at things like this as well, but no solid answers. I was planning to use a lexan window setup, and still may, although the windshield out of lexan is illegal. It properties that make it much quieter than actual glass though, and it wont shatter. Percy's makes some precut for my car, that is extremely scratch resistant as well. They usually set up a windshield at shows with the wipers going full time, with a piece of steel wool between the wipers and the windshield.

Believe it or not, if your willing to go to a smaller side mirror setup, that is a huge improvement in wind noise. I plan to build some out of fiberglass with a convex mirror so I can make them as small as is safe. I drove around without them for a while, just looking over my shoulders when lane changing, and it was a large diff, even before I touched any sound deadening in my car. Gained a slight mpg boost as well. Im looking at doing a full undertray next year, from front to back. I road in a car with one recently (hypermiler), and his car was rediculously quiet, with no additional deadening. Most of the road noise from the floor of the car is actually wind noise upsetting against the bottom of the cars rough edges.
 

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Discussion Starter #9 (Edited)
hmm, I thought lexan was easier to scratch. I've been told (repeatedly) from racing people that if you use windshield wipers on a lexan window it'll get horribly scratched immediately. And do you know where/why it's illegal? Whether it's illegal just in Texas, California, and New Mexico (or wherever) or a federal thing?
 

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Discussion Starter #11
First 8 times I tried to load that when I searched myself firefox crashed :p

Not interested in Lexan anyway, since it scratches so dang easily. Maybe for the rear vent windows and tailgate window but not for a windshield.
 

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Uncoated lexan you buy at a hardware store scratches easy. Treated lexan can be very scratch resistant. I've personally seen the steel wool/wipers test on the percussion speedglass. My old glasses were also lexan, and held up well to motocross, not to mention motocross goggles.
 

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Discussion Starter #13
Hmm, maybe people just buy cheap lexan when they do race cars then.

But it does seem that the lexan windows can be quite illegal for various safety reasons. I've never heard of race people saying lexan is really quieter though.
 

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Its only the windshield that's illegal, and that's mostly based on very old tests. Im willing to bet a modern, coated lexan windshield wouldn't be any less safe than glass. No shattering, no spiderwebbing, much more impact resistant.

The noise benefits are just due to the physical properties. The lexan is much more acoustically dead than glass of the same thickness. Its resonant frequency is also supposed to be lower than glass.
 

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Discussion Starter #15
Actually, the illegality was due to it not shattering. I'm sure you know the procedure for escaping a car if your car has in some become submerged?
 

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Actually, the illegality was due to it not shattering. I'm sure you know the procedure for escaping a car if your car has in some become submerged?
Windshields are designed not to shatter like the side and back glass on a car. The winshield is non tempered glass with a plastic binder in the middle to keep in together when it is broken.
 

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Discussion Starter #17
Okay, shattering isn't the word I'm thinking of. Basically it's because the window needs to be breakable. If someone is in an accident or their car gets submerged, they have to escape out the windshield. Not easy with lexan.
 

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How's about: Reflection defeated/ Refraction induced anything = quieter.

Acoustiglassmyass!

Hint: Transparent micro texture laminate helps defeat reflecting sound waves. I don't know anything other than that though. :cool:
 

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I think if my car gets submerged, im going out the side. My dash would be damn near impossible to climb over and exit through the windshield.

IIRC, the reason they were outlawed is because non-molded flat panel lexan flexes under freeway speeds. That problem was solved with formed lexan windows
 

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Okay, shattering isn't the word I'm thinking of. Basically it's because the window needs to be breakable. If someone is in an accident or their car gets submerged, they have to escape out the windshield. Not easy with lexan.
You will never be escaping a car by knocking out a windshield it is the one piece of glass that is designed not to fall apart. If it was so easy to remove airbags would be useless as the winshield would pop out on deployment.
 
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