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Sound Deadening Idea--Is it bonkers?

Ive done my var after retrofit the dyna audio but i only did the doors allot of work and tbh the sound is better the bass i mean but the efford and the money if i knew back then what i know now i would not have done it saved me like 200 euro
 

dosjockey

Go Kart Champion
Location
South
Ive done my var after retrofit the dyna audio but i only did the doors allot of work and tbh the sound is better the bass i mean but the efford and the money if i knew back then what i know now i would not have done it saved me like 200 euro

Depends on how you do it. For speakers, your mounting location and enclosure make more of a difference than deadening. If you go factory, you lose those potential gains.

Few speakers are genuinely meant to be mounted in an infinite baffle scenario. They like an enclosure, and they like it enclosed.

What you want to do with a door is seal it air tight away from the cabin space. That means all those little cutouts and things used to install window regulators and lighten things up need to be completely sealed with the deadening material. You want the back-wave of the driver to stay in the door or outside of the car. That's where your increased bass comes from in a factory location. The other option is to mount an enclosure to the door panel; which doesn't work easily on modern hard foam panels.

That's for audio, though. It's different than trying to quiet a car.

It's certainly an option for keeping traffic noise out, and it does work very well, but most of the "noise" you notice in a car is being transmitted through body and shock mounts, as well as firewall, vibrating floor, roof, and wheel wells. The doors are actually quite stiff, in that regard. The wheel wells are stiff too, but they're right next to the tires and suspension; so all manner of frequencies get in there. Deadening and insulating those is about shutting them up as much as possible.

More expensive cars will typically feature many laminations of steel or aluminum in those areas to mitigate the issue, and then add deadening asphalt to appropriate areas (same as Dynamat, just a different material), and then carpet with a thick neoprene pad.
 

zwalk

Drag Race Newbie
Location
United States
Car(s)
GSW 4motion
I'm considering doing this myself, another poster said I don't need full coverage? How does that work, just some squares centered in the wheel area in the trunk?

And then under the passenger seats?
 

El_bigote_AJ

Autocross Champion
Location
Las Vegas
Car(s)
2019 GTI bunny
I'm considering doing this myself, another poster said I don't need full coverage? How does that work, just some squares centered in the wheel area in the trunk?

And then under the passenger seats?
You don’t need full coverage of CLD (noico dynamat) products as those are in reality are not meant to be sound barriers.

This original website is now gone but these are archive shots of it that are full of valuable information when it comes to “sound deadening”

https://web.archive.org/web/20210609214849/https://www.sounddeadenershowdown.com/
 

southpawboston

Drag Racing Champion
Location
Somerville, MA
I'm considering doing this myself, another poster said I don't need full coverage? How does that work, just some squares centered in the wheel area in the trunk?

And then under the passenger seats?

You really don't need full coverage. You only need to place pieces in strategic places where resonance may occur in the metal panel due to road vibrations, etc. Covering 25% of the surface area of a large panel with little pieces here and there is 99% as good as covering the entire panel, and you save weight in addition to money as well. The tar-based visco-elastic coverings (Noico, dynamat, etc) really only dampen harmonic vibrations (which create noise) by adding weight to the thin metal, they don't insulate from noise. Foam-based insulation sheets insulate from noise, and I place pieces of that wherever I can behind the plastic door and trim panels, and also on the trunk floor. In the case of foam, coverage is proportional to the degree of noise blocking, so more is better.
 
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zwalk

Drag Race Newbie
Location
United States
Car(s)
GSW 4motion
You really don't need full coverage. You only need to place pieces in strategic places where resonance may occur in the metal panel due to road vibrations, etc. Covering 25% of the surface area of a large panel with little pieces here and there is 99% as good as covering the entire panel, and you save weight in addition to money as well. The tar-based visco-elastic coverings (Noico, dynamat, etc) really only dampen harmonic vibrations (which create noise) by adding weight to the thin metal, they don't insulate from noise. Foam-based insulation sheets insulate from noise, and I place pieces of that wherever I can behind the plastic door and trim panels, and also on the trunk floor. In the case of foam, coverage is proportional to the degree of noise blocking, so more is better.
I am having vibration issues so that's good
 
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