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Discussion Starter · #1 · (Edited)
A lot of people don't realize how important sound deadening is to a car audio system. Proper deadening can…
• enhance sound reproduction and accuracy
• increase volume
• reduce distortion and road noise
• stop rattles
• and enhance mid and sub bass

First off, everything you need to know about sound deadener in general can be found here. Sound Deadener Showdown
I would suggest reading this first before you attempt anything. This guy is a legend…

There are many products out there that are all great so just take your pick. Some work better than others and of course there are price differences.
-B-Quiet Extreme and Ultimate
-Cascade Audio Engineering VB2
-Dynamic Control Dynamat Original and Dynamat Xtreme
-Elemental Designs eDead v1 and eDead v1SE
-FatMat
-RAAMaudio RAAMmat BXT
-Second Skin Damplifier and Damplifier Pro

Now, assuming you read the link I just posted (really hope you did:pissed: ) I will assume you have a general knowledge of things and I will only explain how to deaden the IS300 specifically. Certain areas of the car are problematic and certain areas really don’t need to be addressed. Broad, flat, resonant metal or plastic that has minimal structure or bracing is pretty much the devil. Areas like this need to be deadened much more than areas that have convolutions and structure.

My personal products of choice are made by the company Second Skin Audio, their website found here--->Sound Deadening Materials for Noise Reduction from Second Skin
I use their mat deadener (Damplifier), liquid deadener (Spectrum) and closed cell foam (Over Kill), in my own car and have been totally satisfied. Their products are reasonably priced and are superior to other more expensive brands. It's more expensive than some but I feel like the difference justifies the price difference.

The best way to tell if an area needs deadener, or MORE deadener, is to use the “tap” test. The tap test is just knocking on the area to see if there is any reverberation. If it resonates then you need more deadener until you are content with the sound. If you hit a piece of metal like a Chinese Gong or a symbol on a drum set it reverberates for a long time where as if you hit a piece of concrete you have none. The concrete sound is what you are going for.

Front Doors
The most important area that needs to be deadened in the car is the front doors. This is where sound reproduction originates from the component speakers so it is important these areas are done well. When a speaker moves in and out it creates two different waves of sound. The front wave comes from the front of the cone moving forward, and the back wave comes from the rear of the cone moving backward. THESE TWO WAVES ARE INVERSES; POLER OPPOSITES, AND IF THEY MEET THE RESULT IS NO SOUND The reason for this is destructive interference. If you have one wave up and the other down, their inverse energies cancel each other out. So, we want to kill the backwave with deadener to keep it from interfering with our beautiful front wave. Here is a picture of what I mean…




The above pic is just for reference when so when I say “outer skin” and “inner skin” you know what I’m talking about. Deadener placed on the outside skin of the door will kill the backwave and reduce road noise. Deadener on the inside skin of the door will aid in killing the backwave, reducing road noise and also sealing the door. Sealing the door will DRAMATICALLY improve midbass response from the component speakers even the stock ones can benefit from this. Sealing the door turns the door into an enclosure for a speaker. A subwoofer playing in your hand without an enclosure creates hardly any bass and component speakers are no different. Give them a controlled airspace and they will blow you away by what they can sound like.

Here is a picture of my door deadened and sealed with Damplifier and liquid Spectrum. It is important to note that there are some holes you shouldn’t cover such as the holes the door panel snaps into and small drain holes on the very bottom of the door. When it rains the drain holes are necessary to keep water from pooling in the door. Other than that cover all you can! You can deaden right over wires, this doesn’t harm them and actually works as a way to secure them and keeps them from rattling. Be sure to keep the harnesses that plug into the door free to move since you will need to plug those back in and put the panel back on.





Now the rest of the car is deadened from a road noise and vibration canceling perspective since the main speakers in the doors we have already taken care of. The rear doors don’t need to be deadened since their metal surfaces are less broad and shorter than the front doors. But, like I said, they don’t need to be deadened but you still can….I did because I’m a freak. Let me make a note that the floor, beneath the carpet, does not need to be deadened. The carpet is backed with a 1inch thick lint pad and there are foam pieces under that in the foot wells. Here is a picture of what it looks like under the carpet.


Roof
Now we will move onto the most resonant part of the vehicle….THE ROOF!!1!
If you have ever tapped on the roof you know how tinny it sounds. The roof has NO structure and is just a thin, single piece of metal. You will need to take the headliner off to deaden the roof but the noise reduction is worth it. There is a headliner removal thread made by the My.IS member Dannknee http://my.is/forums/f90/how-remove-headliner-pics-318274/ (thank him for this)
There are also some wires above the head liner that can rattle so deadening over them is a good idea to keep them secure. I did a layer of Damplifier, followed by two coats of liquid Spectrum, and I eventually followed it up with Overkill closed cell foam. Just make sure you have enough clearance for the sunroof to slide back. I also hit the headliner with a layer of Spectrum.

The roof pre-deadener


Here with some Damplifier…


Done with Damplifier and liquid Spectrum…:)


Headliner with Spectrum


Trunk
The next most important place to deaden is under the spare tire. The basin the tire sits in is a single sheet of thin metal that has holes in it fitted with plastic plugs you can pull out if water gets in your trunk. This area is incredibly noisy when driving. Go for a drive with the trunk stripped and the rear seats out and you will think you have all the doors open there is so much road noise. The backseat pads and trunk carpet help with the noise but they can only do so much. I deadened right over the drain plugs and over everything in the trunk. The result was very nice. Deadening the trunk and the trunk lid will kill a ton of rattles (since in all likelihood your sub will reside there) and it will also direct more bass into the cabin since it will not escape through the trunk.




Rear Seat Area
The last part of the car that I think really needs to be deadened is the rear seat area. The rear seat area consists of the metal that divides the trunk and the cabin, under the rear seat bottom, and the rear deck. The rear seats help insulate noise from the rear wheel wells and they also kill exhaust noise. The rear deck needs to be deadened only because it rattles….thats it
I did Damplifier and Spectrum on the rear seat bottom and the trunks metal divider. I think this helped a lot with the road noise as well.



When I had the rear deck removed I deadened the metal with Damplifier. In addition to that, I did two nice layers of Spectrum on the removable rear deck piece with the speaker covers on them. I then added a layer of Overkill closed cell foam to the rear deck piece.


That should cover it! (no pun intended)
If you thought your IS300 was quiet before wait till you finish deadening :shocked:

An added plus that you, as mature people, will like is that the sound from your system stays in YOUR CAR! So even if you like loud music you don’t have to bother the rest of the world with what you are listening to.

Any questions or anything I need to add (or change) let me know:)
 

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Great writeup as usual Italyn. +rep when I can again.

Mods: Sticky ;)
 

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Dang I love to do all that to my ride but I'm not the DYI type of guy ...I suck at that , Wonder if there is any good shop here in LosAngeles that can do that. but then again trusting the shop to strip my ride like that would be the other thing.

+ Rep for great writeup
 

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BumbleCat, buy enough to do both of our cars and I'll do it for you :)
 

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Great write up! I have a few questions:
1. Do you need to prep the surfaces for adhesion (i.e. alcohol wipes)?
2. What is the set up time/dry time of the liquid?
3. How long before you can start puting the interior back together?
4. What was the total time from start to finish?
 

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Discussion Starter · #11 ·
Great write up! I have a few questions:
1. Do you need to prep the surfaces for adhesion (i.e. alcohol wipes)?
2. What is the set up time/dry time of the liquid?
3. How long before you can start puting the interior back together?
4. What was the total time from start to finish?
Good questions!

1)I only did in places that were REALLY dirty like the interior of the door. Other than that the stuff I was using will pretty much bond to anything regardless, the adhesive once it has set a while is incredible!

2)No real setup for the liquid. Just paint it on over anything, even existing deadener. It takes about an hour to skin over pretty good, at which point you can add another layer if you want. I would give it about 12 hours before you put stuff back on it like door panels though. One thing I will mention though, is that until the liquid has CURED completely do not assume anything will stick to it. It cures by way of evaporation so stuff stuck to it will inhibit that. I tried to use spray adhesive to attach closed cell foam to it and it stuck initially but always came off. The cure time is about a week I've been told.

3)Like I said, 12 hours and you can put stuff back together and it will be fine. Just use your judgment.

4)That really all depends on how fast you work and intensely you are deadening. I did a decent amount and it took me all weekend for the whole car. I would suggest doing it in pieces. If you decide to do the doors you should deaden one door with the mat completely and then move on to liquid. I say that because while it's drying you can do the other door. Then come back for another layer. Do stuff like that and you will not find yourself waiting for it to dry.
 

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I am considering putting some dynamat in my car. that is the brand my audio car guy carries, so i try to buy my stuff from him. I dont know what everyone thinks, but I am just thinking about putting the dynamat on my front doors and the rear deck. Is it worth it? or to really hear the difference, would I have to do all of the things done in this thread (roof, doors, back seats....)?
 

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Discussion Starter · #13 ·
I am considering putting some dynamat in my car. that is the brand my audio car guy carries, so i try to buy my stuff from him. I dont know what everyone thinks, but I am just thinking about putting the dynamat on my front doors and the rear deck. Is it worth it? or to really hear the difference, would I have to do all of the things done in this thread (roof, doors, back seats....)?
Doing just the front doors helps the most in my opinion, from a sound reproduction standpoint. This really brings out the midbass and tightens things up quite a bit.


When someone asks "is it necessary" or "how much" types of questions when referring to deadener I can't really answer that. Necessary would mean that the car could not function properly without it and it does just fine from the factory so non of this whole process is "necessary"......but it does IMPROVE a lot of things. So that's also why the "how much" question is almost impossible to answer since you can keep adding deadener and it will get more and more quiet.
 

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Discussion Starter · #16 ·
Stylion - How did you apply the Spectrum (paint brush, spackle knife, etc)? When you did the roof was there any drippage? Thanks again for all the great info!
Actually, i used different things depending on where I was applying it. On flat surfaces I used one of those small roller brushes, that covered a lot of area and never allowed it to get too thick to run. I used that on the ceiling as well as other flat areas. I used brushes on the other areas that were more convoluted.

Spectrum is fairly thick though so you can get a good coat before it starts to run.
 

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Thanks again for the great info, it helped a ton.

I did my trunk, rear deck, rear seat area and roof this week. I did it in three evenings - tear down on Monday night (about 3 hours) - Final tear-down (headliner), damplifier and two coats spectrum (then put headliner back in) on Tuesday night (about 4 hours) - Another coat Wednesday morning (30min) and then final coat and re-assembly on Wednesday night (about 3 hours).

I used damplifier on the roof and in other key areas only (spare tire well & rear seat pan flat spots). I did not take the headliner out of the car, just dropped it and worked over it. I used carpet padding that I got free on the rear deck, between the cover and that rubber mat thing. It compresses well to hold all the wires, etc from vibrating and was free. I could have used more Damplifier (I got the smallest order, 10ft^2) and I wasted money on the sludge, you don't need it, the spectrum is thick enough as it is. If I did it over I would get least 20ft^2 of damplifier (prob 40ft^2 if doing doors too) and one gallon of spectrum (not sludge).

I will get some pics up tonight.
 

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Hey, I dymat extreme a 1ft^2 on the outter door, entire inner door, and now the bass is much tigher. But when I'm out side the car, I can hear some parts of the outter door rattling (around door handle). Any idea how I can fix this? I couldn't dynamat the rest of the outter door as it is mostly not easily accessible. Thanks.
 
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