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Acoustic insulating Project - 3 leaks found so far

c31561

Go Kart Newbie
Location
East Coast, USA
Car(s)
2017 GTI Sport
I have done a fair amount of sound deadening and I have found it needs to be a two pronged approach. You want to reduce the structure borne and the airborne noise. I used a combination of vibration mats (Something like dynamat) for the structure and MLV for the airborne noise. So far I have done the doors and the rear with good success. With every portion completed, I notice how much louder the stereo becomes (Purely in my mind I am sure).

By far the biggest gain was putting a sheet of MLV between the cargo shelf and the trunk liner. It really cuts down the noise from the rear of the car. The drawback to reducing the noise is the addition of weight to the car,. Well worth it to me since this is a daily driver and not a track car.
 

bass_lover1

Vdubber
Location
SE USA
Car(s)
MK7.5 Autobahn DSG
As with anything in life, using the correct tool for the job is important.

There seems to still be a lot of confusion over the purpose of sound deadener, and what it should be used for. That's ok though, it does have its uses but it shouldn't be the only tool used to help insulate the cabin.

There are typically three types of acoustical noises that would happen within a car's cabin:
1) Resonance
2) Rattles
3) I don't have a good word for this one, so we'll call it Environmental noises (think road/tire/wind noise).

Resonance is the energy from some source being transferred to another object, causing it to vibrate. Think of this as the skin on a drum, if you hit it with a drum stick the whole skin will resonate. Now of course with that being the intent of a drum, it isn't an issue. But think if you were to hit one drum, and then the one right next to it also produced a sound. It wouldn't sound proper, right?

This is where sound deadener comes into play. In a car, replace the first drum with your speaker, and the second drum with the panel it is attached to. The speaker causing resonance (which we interpret as sound) is perfectly normal. The vibrations from the speaker causing the panel to also vibrate is bad, it introduces unwanted sound. There used to be a great resource (RIP sounddeadenershowdown.com, actually it looks like it's back up and running so that's awesome) that covered the efficiency of sound deadener, but in short 25% coverage of any panel is sufficient to reduce resonance to an inaudible level. You don't need to go crazy, it works I promise. Plus it saves weight.

Rattles can sometimes be caused by panel resonance, but not always though they have similar causes. Rattles are when two separate panels are touching each other without an insulation barrier between them. Pretty simple fix, find the rattle, and decouple the panels using some sort of Closed Cell Foam around 1/8" thickness is usually enough. CCF is important because it wont absorb moisture.

Environmental noises actually require something to block the sound and insulate you from the world. You should do the first two before you jump this far ahead. You need Mass Loaded Vinyl for this one. MLV is generally used as a commercial noise insulator, but it works in cars, too. You need about 1/lb per sq/ft of weight to be the best balance of effectiveness and weight and it needs to be flexible enough to contour to the area you're installing it in. You'll want to lay CCF down first and then adhere the MLV to the foam to prevent the MLV from rattling against anything. While it definitely works, the downside is you really need to do the whole floorboard to get the best results. If you only do the doors or hatch area, the environmental noises will just come in from somewhere else. Of course, how crazy you want to go is up to you, and you definitely can get results with targeted applications.

Hope this helps!
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
Cheers fellas :)

Noico Red 4mm insulation arrived today. For anyone thats done this, is it better to apply it to the door frame metalwork, on top of the dynamat xtreme? Or directly onto the door trim panel which is obviously removed and set aside?

just saw the above 2 replies. Thanks! Will digest them after dinner. Looks like great info.. Thanks.
 
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Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
I have done a fair amount of sound deadening and I have found it needs to be a two pronged approach. You want to reduce the structure borne and the airborne noise. I used a combination of vibration mats (Something like dynamat) for the structure and MLV for the airborne noise. So far I have done the doors and the rear with good success. With every portion completed, I notice how much louder the stereo becomes (Purely in my mind I am sure).

By far the biggest gain was putting a sheet of MLV between the cargo shelf and the trunk liner. It really cuts down the noise from the rear of the car. The drawback to reducing the noise is the addition of weight to the car,. Well worth it to me since this is a daily driver and not a track car.
Cheers for this 👍🏻 Did you use any sound insulation on top of the deadener but before the MLV? Great that you’re getting results. It’s really rewarding when you’re on the right track. So far my trunk has deadener only and no improvement I can hear of. The other bit I’ve done however is dynamat applied to both skins of the driver door. The new solid sound to it when I close it, is lovely ☺️
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
As with anything in life, using the correct tool for the job is important.

There seems to still be a lot of confusion over the purpose of sound deadener, and what it should be used for. That's ok though, it does have its uses but it shouldn't be the only tool used to help insulate the cabin.

There are typically three types of acoustical noises that would happen within a car's cabin:
1) Resonance
2) Rattles
3) I don't have a good word for this one, so we'll call it Environmental noises (think road/tire/wind noise).

Resonance is the energy from some source being transferred to another object, causing it to vibrate. Think of this as the skin on a drum, if you hit it with a drum stick the whole skin will resonate. Now of course with that being the intent of a drum, it isn't an issue. But think if you were to hit one drum, and then the one right next to it also produced a sound. It wouldn't sound proper, right?

This is where sound deadener comes into play. In a car, replace the first drum with your speaker, and the second drum with the panel it is attached to. The speaker causing resonance (which we interpret as sound) is perfectly normal. The vibrations from the speaker causing the panel to also vibrate is bad, it introduces unwanted sound. There used to be a great resource (RIP sounddeadenershowdown.com, actually it looks like it's back up and running so that's awesome) that covered the efficiency of sound deadener, but in short 25% coverage of any panel is sufficient to reduce resonance to an inaudible level. You don't need to go crazy, it works I promise. Plus it saves weight.

Rattles can sometimes be caused by panel resonance, but not always though they have similar causes. Rattles are when two separate panels are touching each other without an insulation barrier between them. Pretty simple fix, find the rattle, and decouple the panels using some sort of Closed Cell Foam around 1/8" thickness is usually enough. CCF is important because it wont absorb moisture.

Environmental noises actually require something to block the sound and insulate you from the world. You should do the first two before you jump this far ahead. You need Mass Loaded Vinyl for this one. MLV is generally used as a commercial noise insulator, but it works in cars, too. You need about 1/lb per sq/ft of weight to be the best balance of effectiveness and weight and it needs to be flexible enough to contour to the area you're installing it in. You'll want to lay CCF down first and then adhere the MLV to the foam to prevent the MLV from rattling against anything. While it definitely works, the downside is you really need to do the whole floorboard to get the best results. If you only do the doors or hatch area, the environmental noises will just come in from somewhere else. Of course, how crazy you want to go is up to you, and you definitely can get results with targeted applications.

Hope this helps!
Thanks Bass lover. That’s a top explanation 👍🏻 This is what confused me a little. Why are all these YouTube videos showing people doing 100% deadener on Their doors?! Dynamat Xtreme etc... will just prevent resonance, so you only need 25%+ as you said? These folks are using it as though it’s a sound insulator?!!

I think I’ve enough on the drivers door now to proceed with applying the Noico closed cell product. My only issue is where to apply it. Seeing different opinions in different videos.

1. inside the door itself, on the outer skin?
2. On the door inner skin on top of the Dynamat?
3. on the back of the door trim panel/card?

if the correct place is 2, then do I stick it on top of all the electronic modules and wire harnesses on the door? Pic below before Dynamat applied...
F43AE68B-9709-4EEB-ABB2-F97E6262B595.jpeg

Thanks again for your views/info. ☺
 

Ridebjj

Autocross Newbie
Location
lasVegas
I did a double layer of noico mat with red foam on top in the entire hatch floor, under the rear seat and on the inner doors. I did just the mat on the inside of all the outer door shells and a bit under the hood liner.

Result is a more solid feel and reduction in random rattles and vibrations.
 

Yungaxel3

Passed Driver's Ed
Location
SF Bay Area
Car(s)
'19 GTI DSG Autobahn
I just deadened the rear seats and hatch floor with Noico and I actually hear a difference. My 19 GTI didn’t come with carpet on the hatch floor so that could be partly why the sound deadener is more effective. The fender sub sounds more crisp and my exhaust has less drone. Plus overall road noise seems muted just a bit!.

I also ordered Noico 8mm and a bunch of aero goodies. Looking forward to the rest of this project!
 
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bass_lover1

Vdubber
Location
SE USA
Car(s)
MK7.5 Autobahn DSG
Thanks Bass lover. That’s a top explanation 👍🏻 This is what confused me a little. Why are all these YouTube videos showing people doing 100% deadener on Their doors?! Dynamat Xtreme etc... will just prevent resonance, so you only need 25%+ as you said? These folks are using it as though it’s a sound insulator?!!

Because back in the day no one knew any better, and that concept has stood the test of time lol. Deadener adds mass to reduce resonance below the audible hearing range of our ears, it won't block noise.

I think I’ve enough on the drivers door now to proceed with applying the Noico closed cell product. My only issue is where to apply it. Seeing different opinions in different videos.

1. inside the door itself, on the outer skin?
Definitely, it's the largest flat panel on a door, you'll notice results just doing that. The trick is the look at each panel, and find the "individual" sections. Your door has a crash beam, and it's probably welded to the outer skin, so that helps break up the panel into smaller sections. Keep that in mind, any flat panel near bends will add rigidity and doesn't need massive coverage. You'll likely see some factory deadener here already, but they likely use what meets some target performance level while retaining low cost, Noico is likely a better product (I have no proof of this, however).
2. On the door inner skin on top of the Dynamat?
Break the inner door into sections and attack it that way. In your image, the panel near the access hole is weak, but the vertical flat section to the left of the speaker and to the right of the hinge is already pretty strong due to the stamped corner. I'd still probably plop a small piece over those 3 golf ball looking divots.
3. on the back of the door trim panel/card?
Yep, here too. Plastic is a bit harder to treat but it can still be effective and should be attacked the same way. 25% coverage on flat surfaces.

if the correct place is 2, then do I stick it on top of all the electronic modules and wire harnesses on the door? Pic below before Dynamat applied...

You want to go underneath any cabling or modules, and directly to the body work. This stuff is REALLY hard to get off once it's on there, trust me you don't want to have to deal with that if you ever have to replace a body harness lol.
Thanks again for your views/info. ☺

You're most welcome
 

bass_lover1

Vdubber
Location
SE USA
Car(s)
MK7.5 Autobahn DSG
Cheers for this 👍🏻 Did you use any sound insulation on top of the deadener but before the MLV? Great that you’re getting results. It’s really rewarding when you’re on the right track. So far my trunk has deadener only and no improvement I can hear of. The other bit I’ve done however is dynamat applied to both skins of the driver door. The new solid sound to it when I close it, is lovely ☺

You definitely want to insulate the MLV from the deadener with a thin layer of CCF. Hopefully this image gives you an idea of how MLV on a door should be installed. If you can keep it to one piece, that's better since sound can permeate through those gaps.

1606672856132.png


I just finished a 900 mile road trip in my mk7.5, and the noise from the rear is more than I was expecting (first drive lol) so I'll be doing to sound deadening to the hatch area down the road.
 
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Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
I did a double layer of noico mat with red foam on top in the entire hatch floor, under the rear seat and on the inner doors. I did just the mat on the inside of all the outer door shells and a bit under the hood liner.

Result is a more solid feel and reduction in random rattles and vibrations.
Sounds like a good outcome. Any reduction in general noise? Did you consider the Firewall?
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
I just deadened the rear seats and hatch floor with Noico and I actually hear a difference. My 19 GTI didn’t come with carpet on the hatch floor so that could be partly why the sound deadener is more effective. The fender sub sounds more crisp and my exhaust has less drone. Plus overall road noise seems muted just a bit!.

I also ordered Noico 8mm and a bunch of aero goodies. Looking forward to the rest of this project!
It’s an enjoyable project alright. Just so time consuming. If you have a garage and no need to move the car for days it would be great. I don’t have a garage 😞

did you not have any carpet at all?! Or just no underlay under the black carpet?
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
Thanks again Bass Lover. They are great tips and just the guide for me 👍🏻

i won’t go for MLV, this is getting to be a very big job now. I’ve bitten off more than I can chew and I’m doing this all outside in the cold. It was fun at first. 😄

So, I will go for Dynamat Deadener wherever required and Noico 4mm insulation on top on the doors and maybe 8mm in other areas where I can squeeze it in.

Started drivers door. Deadener applied. Then couldn’t figure out the best place to put the Noico 4mm insulation. Ended up fixing it to the inside of the door trim panel. BAD idea. It doesn’t stick well. Lack of contact area and complex shapes and rubbish materials to adhere to. But it will do for now.

Started the passenger door this morning. New plan, take it off the hinges, bring it inside the house where it’s warm and near the coffee machine and do it all in one hit.

Deadener applied. All looms and modules removed. Insulation fixed to the door skin this time. Much better contact this time with the metalwork. It’s not the neatest and it may not last. But at least I could put the components and wire looms back on top of the insulation and it assists with keeping it in place if the glue fails.

5D2D6F21-889F-48FE-BB53-E45EA05C34E0.png

9EC12211-E8F1-4CE7-B65B-08006EA119A2.jpeg

79527193-7AD3-47EF-A0CE-B5D35F27F294.jpeg
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
Hi folks, of course while my passenger door was off yesterday, i moved the car from one car park space to another. Of course this set off the airbag warning light...

Do you need VCDS to reset this or can you do it with OBEleven. I am new to both of these but will buy one if they are reasonably priced. Any idea on cost and/or which i should go for to resolve my issue?

Cheers! :)
 

shovelhd

Go Kart Champion
Location
Western MA
I don't believe that you can reset any airbag light with VCDS. On the MkV, you disconnect the battery, reconnect, and drive it a bit, and it will go away. Not sure about the Mk7.
 
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