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Old 06-04-2019, 11:14 AM
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AudioObsessions
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Default 89 sound deadening

I used to do car audio back in the day. One thing I really don't miss is putting down the sound deadening material. I know it's all worth it in the end but I forgot what a horrible pain in the butt this really is. This is the progress so far, and reflectix is next!


Old 06-04-2019, 11:36 AM
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puterami
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Nice work. I did this recently to my Ranger pickup. Learned to wear gloves due to all of the small cuts on my fingertips.
Good work!
Old 06-04-2019, 12:56 PM
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I'd like to do this to my 89 one day. Did you think to take a decibel reading before this work? I'd like to see this if you did -- before and after.
Old 06-04-2019, 01:32 PM
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Originally Posted by rblakeney
I'd like to do this to my 89 one day. Did you think to take a decibel reading before this work? I'd like to see this if you did -- before and after.
I did not. Most of these companies claim that you're going to hear about a 30% sound difference. I've seen some people on here claim that it's 60% less than what they heard before. It's a Corvette so it will never be as quiet as a Cadillac, and I don't expect it to be. I'm not putting in a big stereo, this was one of those things where when the carpet was out I figured I might as well do it. Any reduction in sound will be better than nothing and I was hoping that this would also help to reduce the heat a little bit. By the time I get to sound deadener in there followed by the reflectix, I'm sure it will be much quieter than what it was before and it will have a lot less heat.
Old 06-11-2019, 02:29 PM
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Reflectix is done! Way cheaper than the precut kits they sell online. Now I just have to foil tape the seams.
Old 06-11-2019, 04:22 PM
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Looks really nice. What's the difference in the two materials?

How far up does it go on the firewall? I'm curious if you hear a reduction in front tire noise.
Old 06-11-2019, 05:32 PM
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Originally Posted by rblakeney
Looks really nice. What's the difference in the two materials?

How far up does it go on the firewall? I'm curious if you hear a reduction in front tire noise.
Kilmat is to deden the sound. Reflectix is to insulate against heat radiating into the cabin. It only runs about halfway up the firewall as I did not remove the sub dash to remove the black mat insulation installed at the factory.
Old 06-11-2019, 09:08 PM
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im going to be doing this soon. Since you have a history with the stuff, I see you went with kilmat, how much difference really is there between the different brands? Ive read several different things but Im guessing a lot is probably personal opinion or advertising. Also how many sq ft did you use, that will make it easier for me to buy mine. How much more do you think the reflectix will help on the heat, doesnt the kilmat reduce the heat already?
Old 06-11-2019, 09:26 PM
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Originally Posted by Blackcorvette_85
im going to be doing this soon. Since you have a history with the stuff, I see you went with kilmat, how much difference really is there between the different brands? Ive read several different things but Im guessing a lot is probably personal opinion or advertising. Also how many sq ft did you use, that will make it easier for me to buy mine. How much more do you think the reflectix will help on the heat, doesnt the kilmat reduce the heat already?
As far as difference between the brands, there is not much. Dynamat Xtreme is the most popular, I will say it is a little bit thicker than some of the others but not worth the price difference. I have used many different brands and yes you will get many different opinions. I have been doing car audio for close to 20 years, the kill Matt seems to be the best value for the money. I used 60 square feet. I ordered a 36 square-foot kit and a 25 foot square foot kit. As far as heat reduction it doesn't do very well for that. I did the reflectix because I wanted as much heat reduction as possible. You can buy the pre-cut kits online but I bought a 100 square foot roll of reflectix and used less than half of it. The role cost me $42, I would much rather spend that then almost $300. The only other thing I used was two cans of 3M spray adhesive. I may have a total cost of 60 bucks into it. To do this it is time consuming and tedious but I believe the end result will be a quieter cabin and cooler as well.
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Old 07-17-2019, 12:34 PM
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Curious about the order of installation. Why did you go with the mat followed by heat barrier instead of heat barrier first?
Old 07-17-2019, 12:47 PM
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Originally Posted by jrobin1
Curious about the order of installation. Why did you go with the mat followed by heat barrier instead of heat barrier first?
The way sound deadening works is by reducing vibration in a rigid panel, that is why it is placed on first. The heat barrier is not rigid so therfore the sound deadening would have zero effect.
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Old 07-17-2019, 01:00 PM
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Thanks. And that makes perfect sense now. I am researching materials and process for doing my 93
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Old 07-17-2019, 01:02 PM
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Originally Posted by jrobin1
Thanks. And that makes perfect sense now. I am researching materials and process for doing my 93
Awesome, if you need any advice let me know otherwise just follow my thread and you'll be good.
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Old 07-17-2019, 01:09 PM
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vette196
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Originally Posted by AudioObsessions
Awesome, if you need any advice let me know otherwise just follow my thread and you'll be good.
He knows his stuff, very helpful. My killmat and tools arrived, I just need to remove the center console and put down the kill mat.

Here is a question,A.O., with the excess kllmat can I apply another layer or will it not make a difference?

Thanks.
Old 07-17-2019, 01:26 PM
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Originally Posted by vette196
He knows his stuff, very helpful. My killmat and tools arrived, I just need to remove the center console and put down the kill mat.

Here is a question,A.O., with the excess kllmat can I apply another layer or will it not make a difference?

Thanks.
You can apply as many layers as you want, the more the merrier! Place any excess in areas where the most noise will radiate from(I. E. Doors, floor, transmission tunnel).
Old 07-17-2019, 04:30 PM
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vette196
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Originally Posted by AudioObsessions
Place any excess in areas where the most noise will radiate from(I. E. Doors, floor, transmission tunnel).
so when I change the door panels, I should put my extra killmat on the outer door skins?

btw, killmat is mfg by the Federation of Russia(might be the only thing I bought from Russia) and of course the flattening tools were made in China...batting 1000%
Old 07-17-2019, 06:31 PM
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Originally Posted by vette196
so when I change the door panels, I should put my extra killmat on the outer door skins?

btw, killmat is mfg by the Federation of Russia(might be the only thing I bought from Russia) and of course the flattening tools were made in China...batting 1000%
Yes you can put it on the outer door skin or you can even put it on the inner as well. On mine I'm going to cover most of the inner door skin in roughly the same shape as the moisture barrier and then put the moisture barrier back over top of that.
As far as the kill Matt being made by the Federation of Russia, almost everything we buy or use has some type of foreign content in it. Even products claim that they are 100% made in the USA have some foreign content in them. We unfortunately will never win that battle as much as we want to.

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Old 07-17-2019, 08:06 PM
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Today I purchased Noico (because it is thicker) for the cabin. I plan to cover that with the Reflectix. I also purchased some Uxcell 394 mil thick waterproof deadening mat that I intend to use on top of the wheel well liners. I have a gap of a couple of inches between the top of the wheel well liner and the fender skin so I plan to extend the mat over the edge of the line to the fender to close the gap. I checked another vette and apparently all of them have this gap.

Do you think the rear of the cabin needs the Reflectix or should I put an additional mat of some kind over the Noico?
Does the Reflectix product (looks like you used the Radiant Barrier) have a self stick backing? If not, did you glue it down?

I bought the car a few weeks ago to fulfill a bucket list item to drive the Route 66 with a good pal of mine. On the way home from Indiana (where I purchased it) to Tennessee, I discovered a lot about the noise and ride of a corvette. ( the one I bought was the first one I had ever ridden in or driven.

Thanks again A.O. for your advice.

Last edited by jrobin1; 07-17-2019 at 08:30 PM. Reason: Added question
Old 07-18-2019, 12:15 AM
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Originally Posted by jrobin1
Today I purchased Noico (because it is thicker) for the cabin. I plan to cover that with the Reflectix. I also purchased some Uxcell 394 mil thick waterproof deadening mat that I intend to use on top of the wheel well liners. I have a gap of a couple of inches between the top of the wheel well liner and the fender skin so I plan to extend the mat over the edge of the line to the fender to close the gap. I checked another vette and apparently all of them have this gap.

Do you think the rear of the cabin needs the Reflectix or should I put an additional mat of some kind over the Noico?
Does the Reflectix product (looks like you used the Radiant Barrier) have a self stick backing? If not, did you glue it down?

I bought the car a few weeks ago to fulfill a bucket list item to drive the Route 66 with a good pal of mine. On the way home from Indiana (where I purchased it) to Tennessee, I discovered a lot about the noise and ride of a corvette. ( the one I bought was the first one I had ever ridden in or driven.

Thanks again A.O. for your advice.
As for the reflectix yes I used the Radiant Barrier. I did put it in the rear as well simply because you have the tail end of the exhaust system there and I'm sure that generates heat as well. It does not have a self stick backing, I use the can of Loctite spray adhesive to hold it all down. Anywhere there was a seam I used the foil tape made by reflectix also. Maybe it wasn't needed in the rear but I figured since I was there I might as well just go ahead and put it in. Good luck, just take your time to make sure that you do it right, and I'm sure the results will be well worth it.
Old 07-20-2019, 03:02 PM
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Hey AO if you are online today I have a couple of questions on the sound deadening. I am removing the rear carpeting, etc. Not sure I should have but I removed the rear speakers. There is an empty cavity behind them with no padding at all only Metal or Fiberglas. Also there is a hollow tube in the speaker assembly about one and a half inch diameter that just opens up inside that cavity behind the speaker assembly. Questions: 1. Should I add any sound deadening in the cavity behind the speaker assembly (or will that screw up the speaker sound)? 2. What is that open tube for and should I do anything with it? (assuming not since it came from factory like that) 3. Should I save the original carpet pad and reinstall it over the new deadening material?

Any advice you can give me will be greatly appreciated. Thanks.

I should have added that my car is a 93

Last edited by jrobin1; 07-20-2019 at 03:08 PM. Reason: add model year
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