# Cheap, absorptive materials for your car



## captainobvious (Mar 11, 2006)

Not that this is *new*, but good info to have out there.

In most cars, you will find many spaces when removing interior panels, seats, and carpet that are open voids of space. If you are looking for cheap, safe and effective materials to help absorb sound in these spaces, have a look at these materials. First though is a look at a typical acoustic wedge style foam which tends to perform better than egg crate and pyramid styles.



Not great performance and it's not a great option in any area that may have moisture.

Now look at the 2 products below:

*Roxul Safe N Sound* insulation.
SAFE'n'SOUND® - ROXUL®

This material has a much nicer NRC coefficient as compared to traditional acoustic foams and is also safer to use in the auto environment as it is water and moisture resistant and does not promote growth of fungi or mildew.

NRC ratings:



And the other option is *UltraTouch recycled denim* insulation from Bonded Logic. 

NRC ratings:



Both of these products are fairly inexpensive and are easily found at most home improvement stores. The Ultratouch you may have to order ahead of time before picking up.


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## danno14 (Sep 1, 2009)

Gotta throw my two bits in on Roxul....

I have seen people post about how they won't use it because it could harbor mold/mildew because it's "an organic" thing. To clarify > it's Mineral Wool, not wool from an animal!

I've used Roxul in various home insulation applications, both for heat and sound proofing, with great success. Thus far, I haven't tried the recycled denim in any application, but have heard of many who have with good results.

Thanks for posting


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## captainobvious (Mar 11, 2006)

I have used both. They are both very nice products. The Roxul breaks apart easier for quicker application which is nice as the Ultratouch is a pain to cut if you have to do a lot of pieces. It does offer the best lower freq absorption though of the group.

Looking at all 3 products, the wedge foam does a nice job in the mid-high frequency area but doesn't perform nearly as well in the lower freq. It's also usually quite a bit more expensive.


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## PickleSlice (Apr 21, 2017)

Has anyone ever stuffed doors with the recycled denim? That stuff is cheap at my local Home Depot, and I need to do something with my doors.


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## Dan750iL (Jan 16, 2016)

I stuffed denim insulation in the void behind the outer and inner skin behind the doors of my extended cab pickup and it definitely made a difference.


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## Justin Zazzi (May 28, 2012)

Rockwool insulation is great stuff. I find it super easy to work with and I shaped mine using a spare hacksaw blade by hand (super easy!).

I've had some in my doors for years and check on it occasionally. There is no growth or discoloration or mildew. You can search my build log in my signature if you want to see photos of how I installed it.

Also, the denim products can absorb moisture but you can prevent that by sealing them in some thick plastic like a painter's tarp, which you can also get at any hardware store.


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## PickleSlice (Apr 21, 2017)

Dan750iL said:


> I stuffed denim insulation in the void behind the outer and inner skin behind the doors of my extended cab pickup and it definitely made a difference.


Looks like I found my weekend project. I'll use spray adhesive on the interior panel, but how did you get it inside the door?


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## Dan750iL (Jan 16, 2016)

Jazzi said:


> ...Also, the denim products can absorb moisture but you can prevent that by sealing them in some thick plastic like a painter's tarp, which you can also get at any hardware store.


I used a 3 mil contractor's trash bag to protect it. I didn't see and signs of moisture back there before I stuffed it in there. I'll still check from time to time as well.


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## PickleSlice (Apr 21, 2017)

Dan750iL said:


> I used a 3 mil contractor's trash bag to protect it. I didn't see and signs of moisture back there before I stuffed it in there. I'll still check from time to time as well.


Did you just bag it, and then just stuff it in there? What about your window regulator?


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## Dan750iL (Jan 16, 2016)

No window regulator in that area.


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## Babs (Jul 6, 2007)

What a coinky-dink.. Just ordered 6 sheets of Owens 703 board. 
3 guesses where that's going Steve and the first two don't count.


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## PickleSlice (Apr 21, 2017)

Dan750iL said:


> No window regulator in that area.


So you just bagged it and tossed it in basically?


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## keep_hope_alive (Jan 4, 2009)

https://m.youtube.com/watch?v=fp71lSN_hH4

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## keep_hope_alive (Jan 4, 2009)

I tall about ultratouch in this video. It is fine as long as it is dry. Roxul is good too.

https://m.youtube.com/watch?v=fna8F6N-9jQ

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## keep_hope_alive (Jan 4, 2009)

When you are reviewing absorption coefficient you must also understand the method of testing used to determine those values. Putting sound absorption in a door will yield different absorption coefficient than on a wall in a room. this is primarily because I'm still up some coefficients are measured with a perpendicular angle of incidence. Sound absorption in doors is more like duct absorption coefficient because sound travels the length of the door as well.

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## naiku (May 28, 2008)

Dan750iL said:


> I stuffed denim insulation in the void behind the outer and inner skin behind the doors of my extended cab pickup and it definitely made a difference.


Remind me to talk to you about this in a couple weeks, $11 for a roll at Home Depot. I might stuff a bunch in my doors, will have to check where the window and everything goes though as I suspect that will all be in the way.


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## captainobvious (Mar 11, 2006)

Good stuff Richard. Thanks for posting the links.


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## captainobvious (Mar 11, 2006)

Ian- make sure you watch the videos Richard posted. You don't want to simply cram the stuff in doors because of potential moisture/mold issues. You can encase it in some thin (0.8-1mil or even thicker) pvc material (painters disposable plastic drop cloth) though and that will keep it dry while retaining its ability to absorb those frequencies.

I believe Richard recommends the standard ceiling tile rigid fiberglass panels for that. They are easy to cut, thinner and can be layered up to the size you want and then encased and installed in the doors.


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## naiku (May 28, 2008)

captainobvious said:


> Ian- make sure you watch the videos Richard posted. You don't want to simply cram the stuff in doors because of potential moisture/mold issues. You can encase it in some thin (0.8-1mil or even thicker) pvc material (painters disposable plastic drop cloth) though and that will keep it dry while retaining its ability to absorb those frequencies.
> 
> I believe Richard recommends the standard ceiling tile rigid fiberglass panels for that. They are easy to cut, thinner and can be layered up to the size you want and then encased and installed in the doors.


Pretty sure I have some of those plastic drop cloths in the garage, I will watch those videos though. Always good to see how people are treating the doors, mine currently have very minimal CLD tile and the holes sealed up. Will be nice to give them a decent makeover next time I have the door cards off.

Those ceiling tiles look like a really easy solution, the holes on my door are much smaller so I would need smaller pieces to put in there. But, looks very easy to do.


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## Dan750iL (Jan 16, 2016)

PickleSlice said:


> So you just bagged it and tossed it in basically?


Yup.


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## Dan750iL (Jan 16, 2016)

naiku said:


> Remind me to talk to you about this in a couple weeks, $11 for a roll at Home Depot. I might stuff a bunch in my doors, will have to check where the window and everything goes though as I suspect that will all be in the way.


Will do.


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## rayray881 (Jul 15, 2013)

What is the purpose of putting this in the front doors where mids are?


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## keep_hope_alive (Jan 4, 2009)

naiku said:


> Remind me to talk to you about this in a couple weeks, $11 for a roll at Home Depot. I might stuff a bunch in my doors, will have to check where the window and everything goes though as I suspect that will all be in the way.


I have come to only recommend ultratouch in dry areas. I won't even put it in plastic bags in doors. I use fiberglass in doors.

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## Babs (Jul 6, 2007)

Yep I'm totally trying the Vedvik approach with absorption and some .8-1 mil plastic and alum foil tape. If I can find something fun to use I'll try the backwave diffuser as well. Understanding of course sound wavelength and diffusion but maybe might help in the low-midrange. Dunno. May just stuff the whole outer door area with the absorption panels and roll with it. 

If I can depending on clearance I might even do absorption panel cutout over the big hole on the front side if it will ride in front of the window without a clearance issue. Then CCF/MLV and card. Might be great. 

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## justgotone (Jun 12, 2014)

All good information guys, thanks for posting, I'm new at this and learning something new every time I get on here. My front doors are treated but not in the manner that is talked about here, the videos are super informative.


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## SPLEclipse (Aug 17, 2012)

FWIW...when I built my 4th order wall I lined the face with a little over 3" of Roxul 60 (see attached picture). I measured FR and THD before and after with literally no difference between the two. Your mileage may vary.


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## rayray881 (Jul 15, 2013)

Glad someone could answer my question........ not so much


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## Alextaastrup (Apr 12, 2014)

Paper wool is better noise insolator compared to Roxul

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## keep_hope_alive (Jan 4, 2009)

rayray881 said:


> Glad someone could answer my question........ not so much


Your question is answered in the video that I posted. If you have any specific questions about how sound absorption works then let me know.

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## rayray881 (Jul 15, 2013)

Thanks!


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## PickleSlice (Apr 21, 2017)

rayray881 said:


> What is the purpose of putting this in the front doors where mids are?



Vibrations, exterior noise, resonance, there's lots of reasons. Like stated, the videos will explain.


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## Babs (Jul 6, 2007)

PickleSlice said:


> Vibrations, exterior noise, resonance, there's lots of reasons. Like stated, the videos will explain.





rayray881 said:


> What is the purpose of putting this in the front doors where mids are?


Absorption that we're talking about here is merely for sound wave absorption, namely backwaves generated from behind the driver, so to minimize backwave distortion and cancellations back through the driver or through the other surfaces back into the cabin.

Not to be confused with dampening of sheet metal by a dampener (Sounddeadenershowdown CLD, Second Skin Damplifier, etc) which is a vibration inhibitor on surfaces such as sheet metal doors, floors etc.

So the purpose of absorptive material in a car door or otherwise behind the speaker driver, such as in a home speaker enclosure, is to "soak up" the sound energy bouncing around, turning that energy into a minute amount of heat (conservation of energy) in the material, so it doesn't color / distort what the driver is trying to project purely from the front side of the driver. 

Sound from the back wave is equally as intense in amplitude as the front wave. And it will transmit back through the speaker or around it, in randomly screwed up phase and response, distorting the front wave of the driver tasked to make music. Absorption from air transmission is specifically for minimizing this back-wave distortion and transmission distortion through and around the driver.

Notice some cutaways some speaker companies will occasionally show of their typical home speakers. They're slam full of absorption material in many cases.










I'll add, the reason folks like Second Skin or SDS or "pick a company" who sell car deadening and MLV products DON'T sell absorption batting or panels etc is because the installation becomes rather advanced as opposed to simply rolling on pieces of metal-backed butyl or a layer of MLV over something. Just in Richard's video you can see there's some forethought for fitment clearance behind the window, custom shaping, covering etc. Also, keeping in mind the products are also widely available in big box.. They're not very specialized, thus not a whole lot of commercial incentive (read: very little profit margin).


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## PickleSlice (Apr 21, 2017)

Babs said:


> Absorption that we're talking about here is merely for sound wave absorption, namely backwaves generated from behind the driver, so to minimize backwave distortion and cancellations back through the driver or through the other surfaces back into the cabin.


Awesome explanation, but would this not help cut down on resonance and vibration? I still plan to use some sort of dampener, but for whatever reason I'm thinking this would help in that are as well.


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## keep_hope_alive (Jan 4, 2009)

PickleSlice said:


> Awesome explanation, but would this not help cut down on resonance and vibration? I still plan to use some sort of dampener, but for whatever reason I'm thinking this would help in that are as well.


Not really. The sound absorption is just loosely adhered to the door. The differences between structural resonance and Airborne resonance. The products that treat one don't necessarily treat the other. When I densely-packed sound absorption in structural cavities I do get results similar to damping products. But this doesn't apply to doors. My doors sound more dead when you knock on them simply because they are more anechoic now and when you test for how dead a door is you are listening to both structural resonance and Airborne resonance.

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## Babs (Jul 6, 2007)

PickleSlice said:


> Awesome explanation, but would this not help cut down on resonance and vibration? I still plan to use some sort of dampener, but for whatever reason I'm thinking this would help in that are as well.


Thanks.. Coffee's flowing strong today. 



keep_hope_alive said:


> Not really. The sound absorption is just loosely adhered to the door. The differences between structural resonance and Airborne resonance. The products that treat one don't necessarily treat the other. When I densely-packed sound absorption in structural cavities I do get results similar to damping products. But this doesn't apply to doors. My doors sound more dead when you knock on them simply because they are more anechoic now and when you test for how dead a door is you are listening to both structural resonance and Airborne resonance.
> 
> Sent from my SM-G900V using Tapatalk


Strikes me that each play a roll as part of the whole tool box to use, from dampening products (CLD), to absorption materials, to decoupling and blocking materials (CCF and MLV). "Use them all" I guess is the take-away.

Hmm.. I should for once crack into my rear doors as well.. I've done zero in there. Not even taken the cards off. At least do CLD if I can muster up some, along with absorption if I can stretch the 6 sheets I ordered. No MLV around though.


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## Justin Zazzi (May 28, 2012)

SPLEclipse said:


> FWIW...when I built my 4th order wall I lined the face with a little over 3" of Roxul 60 (see attached picture). I measured FR and THD before and after with literally no difference between the two. Your mileage may vary.


It is not surprising that 3" of material made no difference in your bass frequencies which have wavelengths between 2-20 feet long. You found out that hard way that this is not the best application of this material.


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## Justin Zazzi (May 28, 2012)

Alextaastrup said:


> Paper wool is better noise insolator compared to Roxul


Why do you think so? Do you have an example of this?


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## Alextaastrup (Apr 12, 2014)

Cellulose wool has typically smaller fibers. That is why it is more tight. I have seen presentation made by one Danish company, which made a box with a soundblaster inside and one removable wall. Reduction was dramatic when they used a wall with 100 mm paper wool. Other kinds of insulation were less impresdive. I will try to find some figures, but not sure I can. 

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## Alextaastrup (Apr 12, 2014)

Jazzi said:


> Why do you think so? Do you have an example of this?


Found one interesting article comprising some comparisons of alternative materials:
Survey on the acoustical properties of new sustainable materials for noise control by Francesco Asdrubali. You might find it easily in pdf-format on www.ciriaf.it

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## Alextaastrup (Apr 12, 2014)

Jazzi said:


> Why do you think so? Do you have an example of this?


Jazzi,
Papiruld Danmark a/s has recently developed a new product called Papiruld Lyd, which insulates about 4dB better than their standard products at higher frequencies. Lyd in Danish means sound. 

Source: www.papiruld.dk/presse/...

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## SPLEclipse (Aug 17, 2012)

Jazzi said:


> It is not surprising that 3" of material made no difference in your bass frequencies which have wavelengths between 2-20 feet long. You found out that hard way that this is not the best application of this material.


The wall was lined to reduce reflection from my front stage. 3" _should_ have helped any reflections proximal to my ears by a lot....but didn't make a lick of difference.


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## Justin Zazzi (May 28, 2012)

SPLEclipse said:


> The wall was lined to reduce reflection from my front stage. 3" _should_ have helped any reflections proximal to my ears by a lot....but didn't make a lick of difference.


Well then I completely misunderstood what you were trying to do there.
Whoops!

But you found zero difference at all? I agree that you should have been able to see _something_ in the measurements. Weather or not that translated into an audible difference is up to you though.


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## Justin Zazzi (May 28, 2012)

Alextaastrup said:


> Jazzi,
> Papiruld Danmark a/s has recently developed a new product called Papiruld Lyd, which insulates about 4dB better than their standard products at higher frequencies. Lyd in Danish means sound.
> 
> Source: Pressekontakt Papiruld Danmark - Papiruld...


Thank you for the information Alextaastrup. I'll take a look a bit later!


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## keep_hope_alive (Jan 4, 2009)

SPLEclipse said:


> The wall was lined to reduce reflection from my front stage. 3" _should_ have helped any reflections proximal to my ears by a lot....but didn't make a lick of difference.


I understand what you were trying to do. It wouldn't effect frequency response by more than a few dB. Treating a room is different than treating a speaker enclosure. Density of the 3" layer would affect absorption coefficients. 





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## Elgrosso (Jun 15, 2013)

keep_hope_alive said:


> I tall about ultratouch in this video. It is fine as long as it is dry. Roxul is good too.
> 
> https://m.youtube.com/watch?v=fna8F6N-9jQ
> 
> Sent from my SM-G900V using Tapatalk


Cool videos, thanks for taking the time!


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## Patrick Bateman (Sep 11, 2006)

Jazzi said:


> It is not surprising that 3" of material made no difference in your bass frequencies which have wavelengths between 2-20 feet long. You found out that hard way that this is not the best application of this material.


^^ correct answer

If you want to absorb 100Hz, you'll need something that's a significant fraction of the wavelength. 100Hz is 11.25 feet long, so you'd want something that's at least three feet thick... or more

I know it's a bummer but the easiest way to get a quiet car is to buy a quiet car... A used Genesis or a used Jaguar is about $20K, little more expensive than a Honda Civic. I drive a Genesis, thinking about a Jag.

And if you look at my Genesis, there's barely any sound deadening. The most important way to make a car quiet is to seal the **** out of the cabin. Every single wire, every single aperture into the cabin is sealed. There are grommets around every last thing. All of the glass is dual-pane. (All luxury cars do this now.) And there's a solid steel wall between the cabin and the trunk. My Mazda is SIGNIFICANTLY noisier than my Genesis but that's because the cabin is far 'leakier.'


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## Elgrosso (Jun 15, 2013)

Yeah go Jag Patrick! 
Which model?


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## DakotaSamuel (Aug 6, 2017)

I was wanting to use the Roxul Safe N Sound insulation for inside the door panels (since it is water resistant), but it looks like it is not sold at Menards which is the only local hardware store. They do have Owens Corning Thermafiber though:
www [dot] menards [dot] com/main/building-materials/insulation/insulation-rolls-batts/owens-corning-reg-thermafiber-reg-r-15-mineral-wool-insulation-3-5-x-15-x-47-24-5-sq-ft/p-1445972379665-c-5780.htm

Would that be similar? It is also Mineral Wool Insulation and looks similar, but I can't find any sound absorption specs for it.


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## DakotaSamuel (Aug 6, 2017)

I decided to go with the Owens Corning Thermafiber, and it turned out pretty well. It was about $18 for a little over 7 cubic feet. It has a density of about 3.8 PCF which compares pretty well to Roxul Safe 'n' Sound (2.5 PCF) and Roxul Rockboard 60 (6 PCF).

With the single roll, I had enough to do a good 3.5" layer on most of the inner door as well as stuff the outer door panel on all 4 doors.

My only real peeve with this stuff is that it does make you really itchy if you don't wear gloves and long sleeves. For that reason, I still prefer UltraTouch Denim Insulation for places that will not see moisture. But I was really pinching pennies with this build and decided to just use the Thermafiber for that instead of spending additional money for the UltraTouch.


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## Redliner99 (Mar 26, 2018)

Justin Zazzi said:


> Rockwool insulation is great stuff. I find it super easy to work with and I shaped mine using a spare hacksaw blade by hand (super easy!).
> 
> I've had some in my doors for years and check on it occasionally. There is no growth or discoloration or mildew. You can search my build log in my signature if you want to see photos of how I installed it.
> 
> Also, the denim products can absorb moisture but you can prevent that by sealing them in some thick plastic like a painter's tarp, which you can also get at any hardware store.


Is the rock wool loose like the denim or in sheets? Is it fiberglass? Hard to find accurate info on it


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## Justin Zazzi (May 28, 2012)

Redliner99 said:


> Is the rock wool loose like the denim or in sheets? Is it fiberglass? Hard to find accurate info on it


Rockwool is similar to fiberglass in that you can get it firm or soft or in sheets or in shapes. Rockwool is much less nasty to work with, doesn't get embedded in your skin like fiberglass does, and you can get hydrophobic rockwool that doesn't absorb water or have mildew problems with moisture like fiberglass does. It is not loose like denim, more like the consistency a really dense/compressed cotton candy.

Try looking for Roxul Safe'N'Sound insulation. You should be able to find that at most local hardware stores like Lowe's.


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## Redliner99 (Mar 26, 2018)

Justin Zazzi said:


> Rockwool is similar to fiberglass in that you can get it firm or soft or in sheets or in shapes. Rockwool is much less nasty to work with, doesn't get embedded in your skin like fiberglass does, and you can get hydrophobic rockwool that doesn't absorb water or have mildew problems with moisture like fiberglass does. It is not loose like denim, more like the consistency a really dense/compressed cotton candy.
> 
> Try looking for Roxul Safe'N'Sound insulation. You should be able to find that at most local hardware stores like Lowe's.


Sweet I'll do that thank you. Would you use Roxul over the blue denim stuff to fill voids and what not as well?


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## Bnlcmbcar (Aug 23, 2016)

I think the difference is negligible but for peace of mind I opted to use both. Figured I would maybe get the best of both worlds: Layer of Roxul and a layer UltraTouch.


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## Truthunter (Jun 15, 2015)

I used the rockwool (1" Roxul AFB) in the doors or anywhere else that may see moisture (like inside the trunk lid). I used the ultratouch in all other areas (that do not see moisture).

You can usually find the 3.5" thick roxul safe n sound at the local HD. You could cut it down thinner but it's not too fun. If you need something thinner, I suggest checking out atsacoustics.com. The Roxul AFB sheets offered there is the same density, are hydrophobic and flexible just like the Safe N' Sound but are offered in 1 & 2" thickness. The also offer the more rigid & dense Roxul 60/80 sheets but at an increased cost.


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## Justin Zazzi (May 28, 2012)

You're right rockwool can be frustrating to cut thinner, but I found laying it flat on the ground with a small piece of wood on either side as a guide while cutting horizontally with a hacksaw blade resting on the guides, worked great.

As for what to use in a car, I've seen condensation in unexpected places and I've seen water leakage in many spots, especially from a clogged drain on a sunroof or air conditioner which can flood anywhere. The huge suck potential of having to deal with wet/mildew denim insulation is so high that I would personally avoid putting it anywhere that would be difficult to remove (especially inside tiny voids and spaces between sheet metal rails etc). Call me more cautious than most, or even paranoid, but that is one problem I never want to have, ever.

-J


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## Redliner99 (Mar 26, 2018)

Justin Zazzi said:


> You're right rockwool can be frustrating to cut thinner, but I found laying it flat on the ground with a small piece of wood on either side as a guide while cutting horizontally with a hacksaw blade resting on the guides, worked great.
> 
> As for what to use in a car, I've seen condensation in unexpected places and I've seen water leakage in many spots, especially from a clogged drain on a sunroof or air conditioner which can flood anywhere. The huge suck potential of having to deal with wet/mildew denim insulation is so high that I would personally avoid putting it anywhere that would be difficult to remove (especially inside tiny voids and spaces between sheet metal rails etc). Call me more cautious than most, or even paranoid, but that is one problem I never want to have, ever.
> 
> -J


So you would or wouldn't use roxul is small tight voids?


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## Ziggyrama (Jan 17, 2016)

Justin Zazzi said:


> Rockwool is similar to fiberglass in that you can get it firm or soft or in sheets or in shapes. Rockwool is much less nasty to work with, doesn't get embedded in your skin like fiberglass does, and you can get hydrophobic rockwool that doesn't absorb water or have mildew problems with moisture like fiberglass does. It is not loose like denim, more like the consistency a really dense/compressed cotton candy.
> 
> Try looking for Roxul Safe'N'Sound insulation. You should be able to find that at most local hardware stores like Lowe's.


Yup, roxul is pretty great. Much better than fiberglass and it also has decent sound blocking properties. I am building an addition right now and it will be fitted with Roxul, top to bottom. I can get R38 in a 2x10 ceiling joist. It is also flame resistant, does not catch fire or smoke when exposed to a flame. And since it does not take on moisture, I may be be able to not use a moisture retardant. Need to check with the inspector on that. Anyways, I know this is in context of a house but overall properties make it attractive for a car application potentially.

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## Redliner99 (Mar 26, 2018)

Justin Zazzi said:


> You're right rockwool can be frustrating to cut thinner, but I found laying it flat on the ground with a small piece of wood on either side as a guide while cutting horizontally with a hacksaw blade resting on the guides, worked great.
> 
> As for what to use in a car, I've seen condensation in unexpected places and I've seen water leakage in many spots, especially from a clogged drain on a sunroof or air conditioner which can flood anywhere. The huge suck potential of having to deal with wet/mildew denim insulation is so high that I would personally avoid putting it anywhere that would be difficult to remove (especially inside tiny voids and spaces between sheet metal rails etc). Call me more cautious than most, or even paranoid, but that is one problem I never want to have, ever.
> 
> -J


Would you use the rock wool in the headliner or just to fill voids?


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## Justin Zazzi (May 28, 2012)

Redliner99 said:


> Would you use the rock wool in the headliner or just to fill voids?


I would not put anything in the headliner or try to fill voids. I doubt I would notice any difference, and there is just too much effort for whatever payoff there might be, including making maintenance that much more infuriating if you need to access anything in those areas.

This is completely debatable however, and you'll hear many opinions on this.


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## Theslaking (Oct 8, 2013)

You know it's not worth it in the headliner. I think CLD is worth it but you find the only air noise comes from the very top of the windshield. It is very noticeable in the rain. But really how often is that? I did it in my Blazer. I haven't done it in a vehicle since.


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## Redliner99 (Mar 26, 2018)

Theslaking said:


> You know it's not worth it in the headliner. I think CLD is worth it but you find the only air noise comes from the very top of the windshield. It is very noticeable in the rain. But really how often is that? I did it in my Blazer. I haven't done it in a vehicle since.


I need something to stop the headliner from rattling against the metal roof and if I'm gonna put anything up there I'd rather put something that will help with some acoustics rather than just foam


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## seafish (Aug 1, 2012)

Redliner99 said:


> I need something to stop the headliner from rattling against the metal roof and if I'm gonna put anything up there I'd rather put something that will help with some acoustics rather than just foam


MLV does not help with acoustics, though it does prevent sound intrusion from the outside of the vehicle. 3m Acoustic Thinsualte does both.

By the time you soundproof your roof the traditional "3 layer" way, you probably will have spent enough money and effort to almost have bought the thinsulate in the first place and used only CLD and the thinsualte to quiet any roof "noise" (rain and/or wind noise from a lumber rack??)

NOT saying it will quiet roof noise as much as the MLV will, but it is certainly meant to help with that and will EASILY insatll under the heading along with the CLD, with ZERO potential for mold or adhesive failure.

just my .02

https://www.cgrproducts.com/using-3m-thinsulate-manufacture-lighter-quieter-cars/


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## Redliner99 (Mar 26, 2018)

seafish said:


> MLV does not help with acoustics, though it does prevent sound intrusion from the outside of the vehicle. 3m Acoustic Thinsualte does both.
> 
> By the time you soundproof your roof the traditional "3 layer" way, you probably will have spent enough money and effort to almost have bought the thinsulate in the first place and used only CLD and the thinsualte to quiet any roof "noise" (rain and/or wind noise from a lumber rack??)
> 
> ...



So thinsulate underthe headliner and roxul in all the voids like the quarters etc sound like a good plan?


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## Locomotive Tech (May 23, 2016)

Sub'd


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## seafish (Aug 1, 2012)

Redliner99 said:


> So thinsulate underthe headliner and roxul in all the voids like the quarters etc sound like a good plan?


Yup...I mean 25 sf of thiinsulate will prolly do it for your roof and cost about $125. Not bad IMO. Do be sure to use at about 30% coverage CLD tiles also on the roof as that WILL help with panel resonance as the roof is probably one of the "weakest" panels in the vehicle as it is large and relatively unreinforced.


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## Redliner99 (Mar 26, 2018)

seafish said:


> Yup...I mean 25 sf of thiinsulate will prolly do it for your roof and cost about $125. Not bad IMO. Do be sure to use at about 30% coverage CLD tiles also on the roof as that WILL help with panel resonance as the roof is probably one of the "weakest" panels in the vehicle as it is large and relatively unreinforced.


I think im at about 80-90% CLD coverage on the roof as of now so I think I'm good there


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## Redliner99 (Mar 26, 2018)

Truthunter said:


> I used the rockwool (1" Roxul AFB) in the doors or anywhere else that may see moisture (like inside the trunk lid). I used the ultratouch in all other areas (that do not see moisture).
> 
> You can usually find the 3.5" thick roxul safe n sound at the local HD. You could cut it down thinner but it's not too fun. If you need something thinner, I suggest checking out atsacoustics.com. The Roxul AFB sheets offered there is the same density, are hydrophobic and flexible just like the Safe N' Sound but are offered in 1 & 2" thickness. The also offer the more rigid & dense Roxul 60/80 sheets but at an increased cost.


Did you put the afb in plastic bags in the door? O just stuck it in there and called it good?


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## Redliner99 (Mar 26, 2018)

seafish said:


> Yup...I mean 25 sf of thiinsulate will prolly do it for your roof and cost about $125. Not bad IMO. Do be sure to use at about 30% coverage CLD tiles also on the roof as that WILL help with panel resonance as the roof is probably one of the "weakest" panels in the vehicle as it is large and relatively unreinforced.


On the thinsulate do you just lay it in there or anchor it some way to the metal ceiling?


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## seafish (Aug 1, 2012)

Redliner99 said:


> On the thinsulate do you just lay it in there or anchor it some way to the metal ceiling?


It is so very light that I have no doubt the headliner itself would hold it up but in my truck, I cut it to fit and then sprayed just a few approximately 3" diameter spots with 3m adhesive to hold it up while I insatled the headliner.


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## Redliner99 (Mar 26, 2018)

seafish said:


> It is so very light that I have no doubt the headliner itself would hold it up but in my truck, I cut it to fit and then sprayed just a few approximately 3" diameter spots with 3m adhesive to hold it up while I insatled the headliner.


Awesome thank you for the help. Did you notice being able to stay warm or cool inside better with the thinsulate?


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## Truthunter (Jun 15, 2015)

Redliner99 said:


> Did you put the afb in plastic bags in the door? O just stuck it in there and called it good?


I did wrap them in plastic and my reasons why are in this post:

http://www.diymobileaudio.com/forum/5270706-post166.html - Post 166

And another post about it:

http://www.diymobileaudio.com/forum/5270722-post168.html - Post 168


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## Redliner99 (Mar 26, 2018)

Truthunter said:


> I did wrap them in plastic and my reasons why are in this post:
> 
> http://www.diymobileaudio.com/forum/5270706-post166.html - Post 166
> 
> ...


That looks awesome where all in the vehicle did you do that?


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## Truthunter (Jun 15, 2015)

Redliner99 said:


> That looks awesome where all in the vehicle did you do that?


Just the front passenger door for now.


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## Redliner99 (Mar 26, 2018)

keep_hope_alive said:


> Your question is answered in the video that I posted. If you have any specific questions about how sound absorption works then let me know.
> 
> Sent from my SM-G900V using Tapatalk


Is this what you used in the trunk in the video?
https://www.homedepot.com/p/UltraTo...lti-Purpose-Roll-6-Pack-60306-16482/202710055


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## preston (Dec 10, 2007)

I just finished my doors. I put rock wool layers into painters 1mil plastic as shown in the videos above. I had insulation on almost the entire back wall of the door. Iniital listening tests the woofers sounded like ass. I played around with a few things and then I remembered someone cautioning against putting insulation directly behind the speaker. 
I removed the insulation behind the driver and it improved dramatically ! So don't insulate directly behind the speaker, despite what is showin in that diagram of a home speaker up above !


In the videos above he did not do so either, putting that giant angle behind the speaker to break up the back wave (I still don't know how he attached that). In my case there was already a convoluted support beam directly behind the driver which should do a good job breaking it up. Otherwise I think the insulation is a pretty good idea, Obviuosly I can't really quantify anything but doors are serious dead


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