To those who have "sound proof'd" their cars...

[dothadance]

^Cascade?? like the dish soap?

[Jean]

Thanks for the link to http://foamforyou.com/ !

[StereoInstaller1]

Now if it were only possible to improve the aerodynamic turbulence of the rain gutters and the windows...

[MC Hammered]

So after reading this thread and getting the marketing that did a good job convincing me it works debunked, what would be the suggested product(s) and application to help soundproof and quiet down the car?

[StereoInstaller1]

If you took apart your E34 and your E30, you really would not see much difference in sound control, yet there is a HUGE difference between the two.

Most of that is aerodynamics.

As I am just about to turn a shell into a car, I am gonna do a couple things I have always wanted to do to an E30. First and foremost, I will do a few strips here and there of thin nitrile sound damping material, maybe 10 pounds total. Second, I am going to remove all of the underhood sound damping material. Third, I will be doing a solid layer everywhere (like up to the windshield, under the heater box, etc.) of the 2 sided "The Insulator", with a second layer on the firewall and transmission tunnel.

I will also be doing the rear wheel wells and the rear sides. Same style, a couple strips of nitrile stuff, then The Insulator. I will likely use Urethane to glue all the roof braces and door braces as well, as the stereo in my black car broke the skin loose from the frame, so the roof and the doors rattle like mad. You can only hear them from outside though.

I will also be doing some sort of expanding foam in the A pillars, possibly an M3 style "glue in" windshield...undecided yet on that one.

I have worked with this "The Insulator" product several times and every time I was just blown away with how effective it is. It does such a good job on heat alone it just might be worth the hassle in my case.

Unfortunately, I will only be able to offer my very subjective opinion on the performance of this treatment, as I will have zero scientific data on the whole "before" part.

Luke

[MC Hammered]

Thanks for the info Luke.

When I ripped out the factory foam sound deadener from under the rear seat, then to find out it is NLA, I had to use Dynamat Extreme as a replacement. It works OK, but the installation of it is a PITA.

I am sure there is a better way to reduce the road noise as I did not want to install the Dynamat again when I get an e30.

I was reading up on the Sound Deadener Showdown tiles as an option, but thought I would ask to see what you suggest to use that is readily available and doesn't cause a mess when installing.

[einstein57]

I bought one of those dynomat knock off rolls from my local wholesale district. I used it mainly on the transmission tunnel and over the headers and cat. I did that mainly cause i accidentally exploded my cat and it was pretty raspy around the passenger foot well. It made a pretty noticeable difference. Yes i'm sure the super think factory carpet pad is better then almost anything on the market but to stop that extra bit of harshness it did the job.

[BrewCity11]

Wanted to add my 2cents.

I'm on the "yes it makes a difference" side here. So I would have to agree to an extent, that most of the benefit is the mass-loading, to lower the resonant frequency.

But, i do have to add in that yes, you are doing some isolation as well. For starters, the doors. Not only have i done the inner skins, like most have here, but i've also "sealed" the "inner cage" too. The surface between the door and the door panel.

Before, you basically have a chamber for the resonance to grow. You add some mass to the inner skin, and you lower the resonant frequency but you still have the chamber. If you seal off the outer cage too, then you i can say i've effectifely isolated some noise.

Same thing with the rear panels. Put some strips on the inner skin, and then seal off the opening.

Again with the rear speaker deck and behind the rear seat. Seal this off well and you won't even have to worry about the trunk.

But one thing i'm curious about. When you guys up there say when you measured, you recorded less than 3db difference???
From my car-audio days i remember a 3db rise(or fall) is effectively doubling(dividing/2) the sound?? Does this apply here? Or is that only for SPL competitions, lol?

[Threehz]

Every 3db's higher is twice the sound and the opposite, every 3db fall is half, so dampening 3db's of noise is pretty good. Maybe just not as good as you would hope from covering an entire car in material.

Good tip though, this thread has given me quite a good idea of how I'm going to dampen my car. Personally it would be nice to take a small sample of all the different kinds and brands of sound dampening/blocking/whatever materials, both made for car use and professional studio use and do small scale testing. Not that hard to make a small sheet metal case with a hole for a mic, line the inside with each different type of material, play white noise at a constant volume level, at a constant distance with all other variables isolated and literally see which work best for what applications and just in general. The main issue I see is you can't buy small quantities of most sound deadeners...

[dwvw]

I find that most damping materials are about the same as far as their acoustical properties. Their adhesion is much more important, and I also hate product that smells.

Another thing, if you have rattles, damping is the last thing you need. You need to isolate the two objects making contact with a open cell foam.

[Cabriolet]

OK, I have my wife's car 100% apart. should i dynamat the floor and inside of the doors? is it worth the $100 it will cost? or is there a good nockoff?

mainly want to reduce road noise.

[MC Hammered]

I went nuts and diid the floor and doors and you can see the work in my touring build thread.

If I only had a $100 budget I'd just do the doors with Dynamat in targeted placement and Dynaliner.

I was very impressed by how much road noise it cut out.

[Cabriolet]

cool thx.
i was gonna get http://www.amazon.com/Dynamat-10455-...ywords=dynamat
i think that will do the whole car

[dwvw]

But one thing i'm curious about. When you guys up there say when you measured, you recorded less than 3db difference???
From my car-audio days i remember a 3db rise(or fall) is effectively doubling(dividing/2) the sound?? Does this apply here? Or is that only for SPL competitions, lol?

You have to double your power (assuming no power compression) to gain 3 dB, but in order for something to sound twice as loud you need to increase by 10 dB.