# My sound reduction journey with some good results.



## country_hick (Mar 15, 2014)

My 1997 dodge ram diesel truck was to loud. I searched far and wide to find the best ways to make it much quieter. I am also thrifty meaning I hate spending more money than necessary to do a job. After reading a ton of information scattered throughout the internet I came up with a lot of research to consider. 

I put that research together here.
Ideas to consider when soundproofing your truck. - Dodge Cummins Diesel Forum

I finally decided my truck needed to actually be quieter and my wallet would have to suffer with that decision. After I took the carpet out I did not see a need for more panel deadening with a CLD. 

Before i started my truck idles at 85dba and going down the road it was at 80-82dba. I am sorry I forgot to get a video of it at stock sound levels.

You can consider this a review of 8lb house carpet padding with a waterproof membrane as a sound deadener. You should be able to find 8lb 7/16" spillguard carpet padding at any carpet seller near you.

When I looked at my truck I noticed the factory did a good job of installing sound deadener. The factory actually did a good job in this one part of sound reduction. My passengers side floorpan had some minor rust. I figured that was because the cupthrower, err... cupholder had lost some drinks in the past. That water on the floor made the factory sound deadening loosen up. I pried that material off and installed some 3M sound deadening where the factory stuff had been. To me that was not really adding more deadener. It was replacing what had deteriorated.

My truck had lots of sound deadener from the factory. As far as I can tell every spot that needed sound deadening got it. That surprised me. There was deadening on the transmission hump, both front floor pans, under the club cab seat, and on all the sides. There was even sound deadening under the kick panels. I only really replaced one bad part of the factory sound deadening. I did not look at it as me adding more sound deadener material like the CLD's.

The 2 places the factory missed completely was the back wall and roof. I did put some spillguard 7/16" 8 lb carpet padding (underlayment) on my back wall. I put 2 layers of spillguard 7/16" 8 lb carpet padding under my trucks carpet. I also added a little above the carpet on the firewall and around the steering column. The nice thing about spillguard carpet padding is it is waterproof. It should prevent your floors from rusting with your wet feet.

I can see that adding some padding under the plastic door panels would probably be a good idea.

After removing the carpet expect to find some rust. Remove the rust then use a good paint. I used POR-15 as it is a rust converting paint.

It looks like the cupholders did not hold the cup very well. I took out the factory sound deadening on this side because of rust and it was loose.


Now the rust is taken care of and the defective factory sound deadening has been replaced.


The drivers side was better.


Now it is good as it gets.


The factory actually did a good job of sound deadening on my truck.

I added some extra sound deadening on the transmission hump where the factory deadening was cut out for a 5 speed and transfer case shifter as I have neither one. This is also the little bit of sound deadening material I had left after replacing the deadener on the passengers side floor pan.


Here we see sound deadening under the club cab rear seat. 


It is time to add the sound absorbing material. It is called foam. I used 7/16" 8lb spillguard carpet padding (underlayment). After applying one layer I decided to add a second layer.

Notice the studs for the seats sticking up. Be careful, they will rip your new foam if you are not very careful.





Use some glue (I used Roberts double sided carpet tape) to hold more foam up in the area above the carpeting on the firewall. I even added some scrap foam to fill in the hole the factory left in the sound deadening material here.


I wrapped a piece of foam around the steering column and added more on the firewall. The ford diesel guys say this is an important area to cover up for sound reduction. Maybe I should add a second layer of foam here.


This is the hardest part of the job. Making the foam fit the transmission hump tightly. If you are wondering, that grey wire is extra length for my power vision tow mirrors.


The foam did not want to lay down with 2 layers. The foam is bunched up.


I sectioned the foam to eliminate the bunching. Then I used aluminum tape to hold it together and hopefully remain waterproof.


Yes, I did put some foam behind the back seat on the back wall.


So far all I have done is 2 layers of foam under the carpet and one layer of foam on the firewall above the steering column on the drivers side.

This is what I used to show DB levels with.


Here are videos showing dba readings.
2 layers of 7 16 spillguard carpet padding under my carpet and sound reduction in my 12 valve - YouTube

Accelerating easily in a 12 valve diesel at around 70db - YouTube

Going up a hill with db meter and 2 layers of spillguard carpet padding under my carpet. - YouTube

The end results so far are 62-63 db at idle down from 85db at idle and greatly reduced noise on the road. My radio went from 28-32 down to 18-24. I could not hear the radio before on level 18. My grand marquis with the same exact radio usually is set at 18-22. 

I can still hear the diesel engine sound but it is not overpowering.

I may use some more carpet padding on my club cab interior plastic pieces. I am very pleased with the sound reduction I now have. Speaking normally moves my sound level meter more than the diesel does as shown in a video above.


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## country_hick (Mar 15, 2014)

As a comparison my 1999 grand marquis idles at around 50dba. 60dba with a -10 is as low as my sound level meter gets so it is hard to say for sure exactly how quiet it is. It is definitely quiet. 

My truck now idles at 62-63dba While this is not as quiet as my grand marquis is when idling it is quieter than the grand marquis driving down the road by a small amount.

Driving down the road my Grand marquis will get up to about 63 dba below 30mph with mild acceleration. It seems to get up to 66dba, perhaps 68dba when getting around 50 mph. Yes, I am sure accelerating hard it would make more noise.

My truck now seems to be at 67-74dba while driving at 50 or less. It seems to be quieter when the torque converter is unlocked. This makes sense. I noticed that at higher rpm's the engine is quieter than at low rpm's. It may also have something to do with full engine power being applied compared to some power loss through the torque converter.

You can see without a doubt that my Grand Marquis is still quieter than my truck. However, driving down the road it is not significantly quieter. The truck used to be much louder than my car would ever be unless perhaps the exhaust fell off completely.

To sum this up.

1999 Grand marquis 50dba at idle 63-68dba on the road.
My now sound deadened 1997 dodge diesel truck 62-63dba at idle. 67-74dba on the road.

Perhaps adding more sound insulation to the doors and other panels would help the truck become even quieter?

I worked on the passengers side door panel. The factory did add some sound absorbing material here. However, it was to little and to thin, at least for me. I added some of the same carpet padding I used on the floorpan earlier. 

The door panel is harder to work on compared to the floor. The door panel has those wonderful curves that make it very difficult to work with. This requires several different pieces of foam and several sectioning cuts to cover the inside of the door panel. Again after getting all of the foam glued in place I used aluminum foil to cover up the seams. Hopefully this also makes it waterproof.

This is the end result of a lot more work than it looks like it should take. It went back on the door without any issues.


I finished up my drivers side door panel today,

This is what the factory gives you.


I took off the small material and left the speaker sound material intact.


I test fitted a sheet of carpet padding.


I added a piece of foam where the mirror mount gets covered up.


I glued down the foam at the top of the door panel.


Here the curve is ready to be covered.


I applied more roberts double sided carpet tape. 


Here the glue is ready for the foam.


I patched in more foam around the speaker hole.


Here the panel is complete except for cutting out the holes for the door handle and window controller. 



Now my door panel is back on the truck.

I can not see much difference in dba between doing the doors or not. However, the truck at least should be easier to cool off now with the added insulation.
Here is why I do not see a reason to add more panel deadening to my truck.
1997 dodge ram diesel cab is sound deadened from the factory - YouTube

The videos below were meant to be used as a comparison of dba levels with the doors done or not. If you have massive bass in your vehicle you will want to foam your doors to prevent rattles.

Here is a video made with the floor and both doors having foam added.
Dba driving uphill with 2 layers of foam under the floor and one layer under the door panels. - YouTube

Here is a video with just the floor having foam added.
Going up a hill with db meter and 2 layers of spillguard carpet padding under my carpet. - YouTube

Here is an idle dba video with just the floor done.
2 layers of 7 16 spillguard carpet padding under my carpet and sound reduction in my 12 valve - YouTube

Here is a video showing dba at idle with the floor having 2 layers of foam and both door panels having 1 layer of foam added.
Dba at idle with 2 layers of 8lb foam on the floor and one layer under the door panels - YouTube


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## Lorin (May 5, 2011)

Nice post and well done. MLV is equally easy to "lay down" on floor panels. If you have a source nearby, it can be had relatively easily (shipping usually jumps the price). I picked up enough for my car for about $150 total a few years ago. After doing multiple cars over the years, MLV and inexspensive jute and\or carpet padding worked the charm this last time.


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## country_hick (Mar 15, 2014)

I used the $.20 a square foot more expensive spillguard because it is waterproof. That cost me about $34 more than standard carpet padding would have. I figure that means if the carpet gets wet the floor will not become rusty. 

I could not find anyone in my state that carried MLV. Shipping just about doubles the cost of MLV. That makes MLV unaffordable.

I was looking for a cheaper alternative to quiet my truck down. It looks like I also got a much lighter alternative compared to MLV. I was thinking I might need to use the toxic metal lead as it is locally available. However, my results are good enough that I do not see a need for it. Hopefully when I replace my cracked dash I can add some more foam under the dash where I can not reach now.

I am hoping the truck also has better performing a/c in hotter weather and more heat in colder weather because of all the extra insulation. When I take the headliner down I will try to add some insulation up there also. The roof will be done mostly to beat the heat.


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## Lorin (May 5, 2011)

Not knocking your results at all, was impressed by them and was merely adding to it. I used an ebay seller for my mlv and I think it ended up being around $1.20 per foot for the mlv delivered. I felt that $150 to do the whole suv, including doors and side panels was money WELL spent. As to the jute, I used the foil backed jute on floors to help with heat. I did also fill body panels in back of car with 3 inch jute in places where water isnt likely to be an issue. Looks like you are well ahead with your issues, thanks for sharing. well done


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## country_hick (Mar 15, 2014)

If MLV was available locally or if I was not so cheap i probably would have used it. using foam I spent about 1/2 what you did with MLV.

I did not take your reply as knocking my results. If MLV had been available locally I might have used it instead. I was thinking of using lead instead as it is available locally. With the results from the foam I see no reason to add all that weight. Someday I may add some lead to my oilpan and valve covers, perhaps even my injection pump to quiet down the engine itself down.

I was surprised at how much sound reduction I ended up with. The one thing that surprised me was no added dba gain from using foam in the doors. I am sure if I had done the doors first there would have been an improvement. 

I used a sound meter and video to show what results I had. i do wish I had thought to do a before video. Maybe I can find another truck without any soundproofing and show that. I am not taking the foam off the floors again.


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## 1fishman (Dec 22, 2012)

Any idea what the 8lbs is in reference to? 8 lbs per yard or ? I'm looking at this to go under my MLV on the floor.

I was looking at this memory foam and wondering if it was the same this stuff. the memrory foam 5' x 8" only weights 10 lbs.

Amazon.com - 5'x8' Multiple Sizes. AREA RUG PAD. Manufacturer: Carpenter Style: Glacier PREMIUM 1/2" 80% Visco-Elastic Memory Foam/20% Rebond with DuPont Spillguard barrier technology. For area rugs, runners and carpet. -


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## country_hick (Mar 15, 2014)

If you chop up a 8 pound carpet pad and stuff it into a box that measures a cubic square foot, the contents will weigh 8 pounds.

You should be able to call any carpet dealer as they can verify this.

I am willing to bet you can buy that same carpet underlayment locally a lot cheaper than on amazon.


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## CZ Eddie (Feb 26, 2012)

MLV vs. Rubber Underlayment for under the carpet?
I did a Google search on this forum for Rubber Underlayment and this thread didn't pop up at all.

http://www.amazon.com/IncStores-Und...433140880&sr=8-1&keywords=Rubber+Underlayment


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## josby (May 8, 2011)

That's pretty cool. This is the first thread I've seen where someone did a before-and-after measurement of their noise reduction efforts. I've never been in a Grand Marquis, but I'd think it would be pretty quiet, so to get that truck down to that close to it is impressive.

Interesting that treating the doors made no difference. I wonder if a different road surface would've made a difference. I.e. if the road you tested on wasn't that noisy, maybe your major noise source is the engine, but on a different road that made more tire noise on the outside of the truck, maybe there would've been a measurable improvement.


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## country_hick (Mar 15, 2014)

CZ Eddie said:


> MLV vs. Rubber Underlayment for under the carpet?
> I did a Google search on this forum for Rubber Underlayment and this thread didn't pop up at all.


The reason is rubber was not used here. I did mention underlayment. I searched for soundproofing, sound proofing, sound reduction, and probably other similar terms trying to find information. My link shown at the top of this thread is as definitive as I could get.



josby said:


> That's pretty cool. This is the first thread I've seen where someone did a before-and-after measurement of their noise reduction efforts. I've never been in a Grand Marquis, but I'd think it would be pretty quiet, so to get that truck down to that close to it is impressive.
> 
> Interesting that treating the doors made no difference. I wonder if a different road surface would've made a difference. I.e. if the road you tested on wasn't that noisy, maybe your major noise source is the engine, but on a different road that made more tire noise on the outside of the truck, maybe there would've been a measurable improvement.


It is possible that a different road surface could make a difference. I am pretty sure that sitting under a bridge with concrete walls the applied soundproofing on the doors and club cab sides would make the truck quieter inside. 

My truck had all of the noise coming from the engine. The old mechanical diesels were not quiet and dodge was less quiet than many others. A friends 1999 (maybe 2000) ford diesel is much quieter than my dodge was. If I have tire noise I could never hear it over the engine. Rolling the windows down now will definitely make the truck noisier.

I forgot to add the part below. Once again I got no additional noise reduction, but the approach is sound.


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## country_hick (Mar 15, 2014)

I applied the plastic layer against the outside of the panel. That way if the foam ever gets wet it should not cause rust on the outside metal skin.

I decided to add the same spillguard carpet padding to my club cab section. 

First, dodge did a good job of panel deadening. Just as they did a good job of deadening the floors they also did a good job of deadening the club cab section. If your truck does not have this treatment you might want to add some CLD material in these areas.


This shows how tall the sound deadening pads are up top where they are not easily seen. If your trucks lacks these add some CLD material to deaden your panel.



After cleaning the metal I added 4 strips of double sided carpet tape. This is what is going to hold the spillguard carpet padding in place. I believe in placing a strip of tape everywhere you have a bump in the mounting surface. That way the tension of the padding wanting to get away from the bump is resisted by the tapes adhesion. 


I discovered the easiest way to install the padding was to roll it up and then squish it into the hole. Inserting the foam as a flat piece was far to difficult. I used a piece of foam and slid it behind the structural member. Sliding the foam behind the brace covers much more area compared to leaving it untreated. I used a piece of foam about 30 1/2" x 22". I need more foam as a 2nd piece after this step is done.



Once the foam is in place The tape needs to be uncovered. The the foam maneuvered into place. The foam will try to get out of place many times and succeed. Keep trying eventually it will be close enough. Pulling the paper covering off the tape is difficult. Everything is hidden and fighting you at this point. The sheet metal you are working near has sharp edges. Expect to get some cuts and scrapes, I counted 24 cuts and scrapes drom doing this job that will be gone in a week or so. 



The foam is in place on the top part of the club cab section.


I used some aluminum tape to keep the bottom of the foam from collecting water.



I put the factory sealed bag of soundproofing material back into place.


I decided since the bag covered about everything down low I would add some more spillguard foam on the bottom below the bottom body line. I placed the waterproof membrane on the bottom. That waterproof barrier should repel any water that comes up from the road. Any water that comes up from below should not cause any rust issues this way (hopefully). I used excess scrap material and made it into a U so it mostly holds itself in place.



Yes, the aluminum foil tape was also used to hopefully hold the foam in place.
This last picture shows what happens when you take the back seat out with just one person. the tabs do not want to just drop into place like they should.


This should help a little with sound reduction. Those who have drone (loud raspy sound from diesels) should find an improvement doing this. I mostly did this to help my a/c work more efficiently. Once I add some foam or low-e insulation above my headliner I expect to have a very cool truck in summer. I went up the same hill I got 74dba from before and had the same dba results with the club cab section done. I expected the same dba results after this work because right now the cummins up front seems to be my only real noise source. The club cab section being soundproofed will not affect noise coming from under the hood. With stacks or a heavy trailer behind me that might change as the exhaust could get louder behind me as the engine works harder.

I did not put anything on the small areas on the side of the window. It is a small area and I was not sure it was worth doing. If I had a lot of noise from that area it would be worth doing. Those with drone may want to also glue some foam on the back of the plastic interior trim piece. I may change my mind and add some there when I change my drooping headliner.


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## CZ Eddie (Feb 26, 2012)

country_hick said:


> The reason is rubber was not used here. I did mention underlayment.


Oops, sorry I posted in the wrong thread.


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## Elvis (Jul 2, 2015)

country... you might be interested to know that Spillguard pad is not waterproof. 
It's an open-cell foam (like almost all carpet pads intended for use in a home).
It does have a moisture barrier on one side, intended to prevent spills from soaking into the foam, but liquids can easily soak into any unsealed edge or penetration. However, the edges could be sealed with a proper glue/sealant. This moisture barrier acts like Tyvek house wrap in that it prevents liquid water from soaking through but allows vapor to escape from underneath (when installed in its normal orientation).

Spillguard is still a "rebond" pad (meaning it has small chunks of recycled foam embedded in it, which makes it a little more susceptible to water penetration than "frothed" pad (e.g.: Menards # 7011303) or "prime" pad (e.g.: Lowes # 590951). But all of these pads are open cell. Most carpet pad stocked in big box stores or carpet dealers is rebond pad, so these two types are more difficult to find, but IMO it is worth it. Most "prime" foam has a higher quality moisture barrier on both sides.

Carpet pads like these are referred to as a memory foam but I've examined every so-called memory foam carpet pad I can find, and based on the way they feel to me, it must be a marketing term because I don't think their resilience is anywhere near as slow as a memory foam mattress topper. 

bergad.com has a couple pages that explain the difference between Viscoelastic (memory) Foams and High Resilience (seat cushion) Foams.

"*Viscoelastic foam, or memory foam, is open-cell, flexible polyurethane foam that has a slow recovery* that can be controlled by its formulation. In other words, when it is compressed, the foam does not quickly bounce back to its original shape; instead the foam slowly conforms to the shape of and supports the weight of the object compressing it with incomparable comfort, vibration, and shock control. Viscoelastic foam’s structure, mode of function, and slow recovery make it the best material in the world for comfort, shock absorption, and vibration/sound damping applications."

"High Resilience foam, or HR foam, is open-cell, flexible polyurethane foam that has a less uniform (more random) cell structure that helps add support, comfort, and resilience or bounce. HR foams have a high support factor and greater surface resilience than Viscoelastic foams. Unlike Viscoelastic foam, High Resilience foam has a very fast recovery and bounces back to its original shape immediately after compression."

One metaphor that helps conceptualize the difference is:
*High Resilience foam is like a spring.* Its firmness in PSI or ILD is like the spring rate.
*Viscoelastic (memory) foam is like a shock absorber.* Foam that is denser and has lower resilience is more like a stiff shock absorber.
In this context, "resilience" has nothing to do with a foam's durability or resistance to "breaking down" over time.

A High Resilience foam is better used as a decoupler supporting a limp mass barrier. The optimal decoupler is a lot less firm (<1psi @ 25% compression) than the closed cell foams (>5psi @ 25% compression) commonly used in aftermarket automotive composite decoupler/barriers.

A viscoelastic material like memory foam is best used as a dampener, and the specs of materials made specifically for dampening reflect this (they are like memory foam, but a lot stiffer). I think that a 1" thick high density memory foam securely adhered to exterior panels would provide substantial reduction in resonance (as well as about R4 of thermal insulation). I haven't tested the dampening effect yet, though.


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## Elvis (Jul 2, 2015)

For anyone contemplating doing what the OP did, another product to consider is Bonded Logic UltraTouch Denim Insulation. While it may not be a good idea to install this inside the outer door skin of any door with a roll-down window, it would work inside the door panels, behind the rear seats and dash, and of course, under the carpet.

The manufacturer's spec sheet shows excellent acoustical performance (high STC and high NRC), along with good thermal R-value too. Home Depot sells the UltraTouch # 60301-48752 48 in. x 75 in. foil-faced Denim Hot Water Heater Blanket (25 sq. ft.) for $28.


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## Slusbe (Jun 27, 2006)

country_hick - awesome write up. I love seeing some actual data to back up your subjective observations. Especially when you used an alternative method tot he tried-and-true MLV+CCF. I may be taking your route if I can't find any MLV in my area.

Elvis - Do you know of any high resilience closed cell foams with a suitably low firmness to serve as a decoupler?


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## country_hick (Mar 15, 2014)

Elvis said:


> country... you might be interested to know that Spillguard pad is not waterproof.
> It's an open-cell foam (like almost all carpet pads intended for use in a home).
> It does have a moisture barrier on one side, intended to prevent spills from soaking into the foam, but liquids can easily soak into any unsealed edge or penetration. However, the edges could be sealed with a proper glue/sealant.


I realized that the plastic barrier was the only thing waterproofing the material. As a result I placed the plastic part against the sheet metal parts where water might intrude. The exception was on the floors. Water would come from the top so the plastic part was also placed on top. The aluminum tape was added to keep water away. Hopefully it will work long term. I was unaware of any other options for keeping the edges from sucking water.



Elvis said:


> For anyone contemplating doing what the OP did, another product to consider is Bonded Logic UltraTouch Denim Insulation. While it may not be a good idea to install this inside the outer door skin of any door with a roll-down window, it would work inside the door panels, behind the rear seats and dash, and of course, under the carpet.


I have seen similar type materials hold water and then cause serious rust problems. It might make sense to use this type of material if you also add a thicker plastic on top to keep water away. There is no way I would use an organic water holding material where water could ever get to it.



Slusbe said:


> country_hick - awesome write up. I love seeing some actual data to back up your subjective observations. Especially when you used an alternative method to the tried-and-true MLV+CCF. I may be taking your route if I can't find any MLV in my area.


Thank you for that. When i did my research I cam to the conclusion that there was no way to know what if anything really worked. Almost every write up I saw basically said "wow!!! what an improvement". I still do not know exactly what that means. I decided to be more precise in my writeup.

As a FYI only using one layer of carpet padding netted me about 67-68dba at idle. The second layer only took away about another 5dba at idle. I did not test on the road to say what difference it made in motion.


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