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Discussion Starter · #1 ·
My former car was a Scion xB, which I gutted, covered all holes (such as in the doors) with thin sheet aluminum, applied a sound deadening layer of something similar to dynamat, and then glued a layer of sound absorbing foam (sold by the yard in sheets). The results were amazing; I could barely hear my Borla exhaust and would sometimes roll the window down to catch a bit of it's rumble.

I saw pictures on this forum recently where someone was installing a sound system, and noticed that spare tire well had nothing in the way of sound deadening. I removed all the easy parts that covered the spare tire well and battery cover yesterday, and used up most of the left-over materials that I had from my former Scion job. The spare tire well seems like it could be a substantial source of road noise. Without the spare tire installed, it seemed very thin; a few wraps with my knuckles transmits more noise than a kettle drum. I installed a single layer of the sound deadening mat, and it did not seem to change it that much. I added a second layer in some places, and then put a single layer of the foam over the mat. I also put the mat on the exterior surface of the battery cover, which appears to be made out of thin galvanized steel. I then re-installed the spare tire, being sure it was tightly secured with its bolt; I think the tire actually adds quite a bit of rigidity of the well. I also replaced all the other covers, and then took it for a ride.

My perception is that the rear of the car is quieter in terms of transmitting road noise. Now the front seems louder to me, of course. I would like to have covered the rear wheel wells, but I was not sure how to removed the covers and I didn't want to break any retaining clips. So I have a couple questions:

1.) Has anyone removed the rear wheel well covers (where the rear speakers are located), and how did you do it?
2.) Has anyone put sound deadening materials in the front floor or door areas, and did you encounter any problems with removing carpet, covers, or moving wires?
 

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Road noise is my biggest complaint about this car. I have not yet tackled the issue but I am very interested in any responses here. Thanks for telling us about the improvments you made to the rear of the car. I am going to start in the front.
 

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You'll need to either get a subscription to Toyota's Technical Information Service here:

http://techinfo.toyota.com

and look for the correct service document. Or a poster in the following thread has kindly made a torrent of the entire service manual.

http://www.ct200hforum.com/forum/lexus-ct200h-general-discussion-forum/118341-ct200h-workshop-manual-3.html#post1651837

Then you can properly determine how to disassemble the sections you desire. I've disassembled much of the interior in order to combat squeaks and rattles. The service manual is an absolute must for determining the proper way to do this.
 

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I too noticed much road noise and think it mostly comes from the tires and is transmitted thru the fenders. I plan to remove the fender liners (on the outside of the car, they are some felted material) and paint several coats of QuietCar sound deadener on the inner fender as I have some left over from a prior car project. I did this on my last car, a 2008 MINI Cooper S and it made a big difference. I think Peckhammer has a good idea and will also do some sound deadening on the spare tire and battery area. I also have a bunch of left over Raamat (similar to Dynamat) from prior cars which is sometimes easier and faster to work with on some interior areas.
 

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Discussion Starter · #6 ·
Thanks for jogging my memory with the mention of RAAMat. That is the product I used, and the foam was called Ensolite IUO. I just looked at the RAAMaudio web page and notice that the foam is now available with an adhesive backing, which is a nice improvement for some applications. You can also get it without adhesive (to be used with a spay adhesive, or no adhesive).
 

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I thought I remember reading somewhere that the spare-tire well transmits a ton of sound. I also think the front wheel wells are light on insulation. Wish I knew someone that could do it for me.
 

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I thought I remember reading somewhere that the spare-tire well transmits a ton of sound. I also think the front wheel wells are light on insulation. Wish I knew someone that could do it for me.
So would not putting some sound absorbing material in the spare tire well do any good?
 

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Discussion Starter · #9 · (Edited)
So would not putting some sound absorbing material in the spare tire well do any good?
Sound absorbing material is only one part of the equation. The first step in noise control is to minimize panel resonance caused by vibrations transmitted by the engine, exhaust, suspension, and road. The spare tire well in the CT is a great example of panel resonance; the well is effectively a speaker and transmits noise. The solution is to add vibration dampening, which can be done with RAAMat or other similar products. You could attempt to block the transmitted noise with sound absorbing material, but you'd need so much of it (in terms of thickness), that you'd end up reducing the interior capacity of your car. ;)

Thus, the most effective solution is vibration dampening material + closed cell sound absorbing foam. Together, they do the job without excessive layering.
 

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To BLOCK noise from coming in you need a mass loaded barrier. Such as MLV
The dynamat/raamat/damplifier is used to absorb vibrations
Will damplifier block some outside noise? Yes. Will it do so as well as MLV? No

Also I have used all and I will only use second skin audio from now on.
I have a bunch of SSA stuff on order for my upcoming CT200 SQ install. I will post plenty of pictures !
 

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I'm going to bump this thread as it was raining yesterday - went over a puddle and the noise seemed like there was a 1mm layer between me and the water! I've just really now understood how loud the road noise is in this car.

I sit in my bmw and while it is a convertible and a 3 series, it is just much quieter!

Definitely need help with the sound deadening :(
 

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Would the rubber spray like quiet car work for the spare tire compartment MVH or should I get some SSA? I am going to take off the inner liners of the wheel wells and coat them in this spray and I am sure I will have extra.
 

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To BLOCK noise from coming in you need a mass loaded barrier. Such as MLV
The dynamat/raamat/damplifier is used to absorb vibrations
Will damplifier block some outside noise? Yes. Will it do so as well as MLV? No

Also I have used all and I will only use second skin audio from now on.
I have a bunch of SSA stuff on order for my upcoming CT200 SQ install. I will post plenty of pictures !
This = winner; what kind of SSA stuff?
 

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I have just done the rubber undercoat on the wheelwells as well as the spare tire compartment. Unfortunately I am going in for knee surgery tomorrow and will be unable to drive for about 10 days. I will let you all know how it goes when I get back behind the wheel.
 

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I have just done the rubber undercoat on the wheelwells as well as the spare tire compartment. Unfortunately I am going in for knee surgery tomorrow and will be unable to drive for about 10 days. I will let you all know how it goes when I get back behind the wheel.
Good luck with the surgery gs. Drop in a line about your progress, and wish you a speedy recovery.
 

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Thanks guys. All I did was take the tire out and spray all the metal that was showing. I am going to put some liner in there as well when I am able to walk again and that should help quite a bit.I am not sure how the rubber in the wheel wells will work yet, but I am hoping it takes some of the noise of salt hitting the underside. But there is so much plastic under the car I don't think will help as much as I am hoping it will.
 

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So all I did was the spray rubber on the wheel wells and in the spare tire compartment. Even without other sound insulation the ride is quieter and I am not noticing as much salt noise coming through. Soon the engine compartment is going to get some sound deadener on the hood and then some more in the trunk compartment.
 
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