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tC sound deadening tutorial

7077 Views 3 Replies 3 Participants Last post by  CJandMJsMatrix
To make things clear from the begining, I own a sound deadening products company but I am a dedictated car audio and performance enthusiast first and formost. I am not here to sell products, I am here to offer insight on how to make your car a much better place to be, not only for better audio but the significant reduction in road noise makes driving more enjoyable all the time.

This is part one, there will be at least one more, possibly two more sessions as we learn more about this particular car.

Since there are so many different levels of what you may be after, lowest weight gain, highest possible results and not worried about the weight, building an SQ comp or SPL comp car, etc, etc, this can become a rather complicated tutorial but I will do my best to address the varying levels and methods required to acheive your goals, no matter what brand you choose to run, I will do all I can to help you, that is the way we have always operated and will continue to do so.

The next post will be my general install guide with some specific tC areas covered in depth, pay particular attention to the rear side panes, the one beside the rear seats;)

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General deadening guide, specific areas will be edited to support the tC's main noise areas in a future postings as we move on to those specific areas. For now suffice to say most of the car is fairly decently deadened from the factory yet certain areas are just not done anywhere near where they should of been.

Here is what I recommend, this is from years of experience and alot of customer feedback, it works very well.

-Front doors, doors with speakers, remove door panel and plastic moisture barier, toss it in the trash.
-One layer of mat on most of the outer door skin, (2/3 coverage is ok on our big doors)overlap the seems, add two more smaller layers, about 12" sq, behind the speakers. Then the same size piece of close cell foam on top of those layers(ensulite foam is best.
-Check for loose wires, cables, etc, inside the door, secure with foam tape, tie wraps, etc. build up the speaker mounting location by making a solid baffel that you can screw to the door then the speakers to it, MDF works great and easy to work with. (gutted stock speakers work great:)
-Seal up the door access holes with a piece of tin, I use perforated aluminum, this gives the next layer of mat something to stick to and tightens up the midbass response.
-Install one layer of mat over the inner door metal, seal all air passages possible, cut the mat back around 1" from edge of door panel. (2-3" on the top and rear side is fine)
-Add a layer of 1/8" close cell foam, ensulite again is best but hard to find, to the top of the mat, cut around all mounting points, same for the mat, to make sure the door panel will fit back on ok, cut back around 1/2" from edge of panel.
-Tap on the back of the door panel, being plastic it will have resonate areas. Add patches of mat to those areas until it sounds deadened, usually about 1/4 to 1/3 of the surface is enough, install the panel and test the the door, slam it a few times and listen for rattles, etc.

The next area is the most critical on the whole car!!!!!!

Rear side panels behind front door location(rear seat side panels) This is the worst offender by a huge margin over the rest of the car.

-Remove rear seat bottom and rear side trim panels. Remove the factory felt cushion located on the bottom, just laying there, take it out for now.
-Install your particular favorite brand of deadening mat over the whole outer skin area(if trying to save weight, cost, etc, cover the stock mat and at least 1/2 of the total outer skin area in wide stips.
-Mat the wheel well area inside the outer area adjacent to the outer skin.
-Install a layer of foam(ensolite is the best) over the entire inner area of that section of the car.
-Mat around the speaker location up to and on the speaker baffle, then foam over that.
-Tap on the back of the side trim panel, lift the felt out of the way and place sections of mat on the more resonate portions of the panel.
-Silicone sealer, etc, use it on the wire connectors, wireless key reciever, etc, etc to elimate possible resonate areas.
-Reinstall the factory felt block and then the trim panels. There is a big gap under the trim panel the seat bottom covers, I like to stuff a big chunk of foam rubber in it.
-Mat the floor under the rear seat on all unmated areas and over the factory mat, or to save material, thump the areas with your fist or a rubber mallet and mat the most resonate ones.
(on our project car we removed all factory deadening which is alot of work and are replacing it with a full layer of mat, two in a few key spots, we will end up about the same weight as stock and have a huge gain in noise reduction)
-Add a layer of foam to the floor under the seat ,best to cover it all.
-Reinstall the rear seat bottom and go for a drive, you will be amazed at the improvement.

This is probably 70% of the net gain you will get from deadening the car, it is that critical to do and do correctly, totally blew me away and I knew it was the worst part to deal with!!!!

tC Floor is fairly well deadened stock, will not have to do this much below, will do a more specific guide as soon as we finish our buddies car and ours.

Floor, Going all out, one layer everywhere, tap on the floor and add a second and sometims a third layer to the resonate areas only, any more is a waste of mat and effort, once and area is deadened, there is nothing more to gain with adding more mat.
-Some tend to over use the mat in some areas and not enough in others.
-Add a layer of 1/4" close cell foam or two layers of 1/8" then the factory carpet, done!


Roof, not usually needed, least results, alot of effort, once the rest is done, test and decide what to do. On a black or very dark vehicle, a tremendous amount of heat build up can occur on the roof, one layer is the maximum I would use the cover it then add a solid layer of close cell foam. (Nothing there to mat really, a bit of foam here and there could help a bit though;)

If you have an exceptionally loud exhaust and or tires, they are the worst offenders as they permeate the air around the vehicle and penetrate from many areas. Sometimes they have to be changed no matter how well matted, just want you to be aware of this issue.

I am going to post this on another forum but this is home base for me and wanted to do it here first:)

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Nice post. I noticed on my first road trip i took that it did seem a bit loud in the car, and was wondering if there was anything I could do to quiet it down. And here you go posting this, perfect timing.
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RAAMmaat is the best bang for teh buck!
did almost 1 roll in my XRS, still got the rear qtr panels to go. myra's RS 1.0 is up next. thanks for the specific application tutorial rick!
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