# MLV with Foam -- might be counterproductive in a car



## dbiegel (Oct 15, 2006)

I've used MLV extensively before but there are two things I'm wondering about before I line the rest of my new car with it.

The general recommendation here is to decouple. However, I've come across a number of sources that say decoupling can actually make low frequency performance significantly WORSE. For example:









1) So if a vehicle is decently deadened otherwise -- ie high frequencies not really an issue -- I'm wondering if NOT decoupling the MLV would actually yield better performance in a car and help with the troublesome low freqs. Thoughts?

2) Has anyone tried using a heat gun on MLV to get it to form better around contours? Or any other tricks for making it easier to contour to a convoluted floor pan without making the carpet stay weird afterwards?


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## VP Electricity (Apr 11, 2009)

The analogy seems suspect to me... I've read the Green Glue website and I'm not clear that we are talking apples and apples. The drywall actually becomes a piston generating sound if not properly controlled, as I understand it...


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## Ziggy (Nov 29, 2007)

yeah, drywall vs steel metal floorboard isn't a good comparable to justify the same results the graph is displaying... I also think that keeping sound "out of the vehicle" is the primary purpose of MLV... at least in my application it would be...
It's kinda scary how that graph is lowest between 63-100 Hz, though (the audible freq of a sub) :surprised:


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## Rudeboy (Oct 16, 2005)

It's true - Green Glue has some very out there "documentation" on their site. As VP Electricity said, a lot of apples to oranges comparisons. Seems like a reasonable product, but some of their stuff makes you wonder.

All of that said, decoupling is overplayed in this application. It makes great sense in theory, but in practice, it doesn't seem to do much. One of the major online sellers of MLV describes all of the important reasons you need a decoupling foam layer, but when you compare the STCs for the two products, there is no difference :surprised:

In my testing over well damped steel, 1/4" of foam makes no difference until you hit 1kHz when it starts absorbing. Below that and the two fluctuate a few dBs up and down. You do run into problems over very resonant steel, but you shouldn't have that anyway. I'm going to have to revisit this. I brought up the same point a while ago and allowed myself to be convinced that I was wrong.

The concept makes sense for a number of reasons, but most of them would require a MUCH thicker decoupler than is practical for us. The 1/4 wavelength rule seems to apply. Even so,most noise has a high frequency component so attenuating it doesn't hurt. 

Heating MLV doesn't really do the trick. You can get it to follow a slightly tighter radius, but you really have to heat the hell out of it and you can't really get it to follow a complex contour.


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## Ted White (May 19, 2009)

There's no "out there" documentation. All very standardized for the construction industry. All following standard ASTM guidelines and data from independent certified acoustic labs. What you guys are doing isn't construction, so things are a little different. 

Decoupling: Not applicable for damping car body parts. The reason is that along with the physical disconnection of material layers, there is the understanding that a significant sealed air cavity will be imparted. This is a 2-3" space requirement. Again, not applicable for what you are looking to achieve.

Green Glue is also not applicable for what you're doing. There are two types of damping systems. The first is Extensional Damping. Painting on a thick layer of a rubbery material that will reduce the (steel) material's ability to conduct a vibration. This again is a surface "painting." Glueing MLV to steel would be another example of Extensional Damping.

The second type of damping is Constrained Layer Damping. This is the use of a different damping material (Green Glue, etc) and reequires the Green Glue to be constrained between two layers of material. Two pieces of drywall, etc. Again, not what you are looking to achieve.


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## dbiegel (Oct 15, 2006)

Thanks for sharing your thoughts everyone. I just wanted to get some discussion on this going since we all want quiet cars -- of course -- but there doesn't seem to be much information on this stuff dealing with our application. 

Ted -- I'm not sure that I understand. Are you saying that decoupling is useless in a car, or are you saying that the graph I posted doesn't apply to cars? Also, you know, the most popular "sound deadening" products for cars are actually vibration dampers (butyl with aluminum foil constraining layer). Your products seem to be very well regarded by the home theatre guys and I've been wondering for a long time if it might be a viable alternative for us car guys instead of the butyl stuff. Would it be suitable for this and if so how would you compare it to the butyl/foil products?


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## OSN (Nov 19, 2008)

dbiegel said:


> Thanks for sharing your thoughts everyone. I just wanted to get some discussion on this going since we all want quiet cars -- of course -- but there doesn't seem to be much information on this stuff dealing with our application.
> 
> Ted -- I'm not sure that I understand. Are you saying that decoupling is useless in a car, or are you saying that the graph I posted doesn't apply to cars? Also, you know, the most popular "sound deadening" products for cars are actually vibration dampers (butyl with aluminum foil constraining layer). Your products seem to be very well regarded by the home theatre guys and I've been wondering for a long time if it might be a viable alternative for us car guys instead of the butyl stuff. Would it be suitable for this and if so how would you compare it to the butyl/foil products?


That depends on your definition of 'sound' in 'sound deadener' - it's sometimes used in the context of vibration dampener and doesn't completely cover it. It deadens vibrations and the 'sound' the resonating panel makes, but doesn't block or reflect the 'sound' of road noise or music very well at all. In home theater, there's more leighway to build a massive wall of layers. In cars, you're limited to about 1/2" in a lot of spots that you want to block sound. I picked up a bunch of Damplifier and Luxury Liner Pro for sound barrier. Luxury Liner Pro has a 3/8" closed-cell foam layer to de-couple and mass-loaded vinyl for blocking and reflecting sound. These are demonstrating to be very effective in quieting your car. There are a lot of threads here with very useful information.


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## falkenbd (Aug 16, 2008)

dbiegel said:


> 2) Has anyone tried using a heat gun on MLV to get it to form better around contours? Or any other tricks for making it easier to contour to a convoluted floor pan without making the carpet stay weird afterwards?


Glue or velcro it down.


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## Rudeboy (Oct 16, 2005)

Ted White said:


> There's no "out there" documentation.


This seems "out there" to me and "apples and oranges".


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## Ted White (May 19, 2009)

dbiegel said:


> Also, you know, the most popular "sound deadening" products for cars are actually vibration dampers (butyl with aluminum foil constraining layer).
> 
> I've been wondering for a long time if it might be a viable alternative for us car guys instead of the butyl stuff. Would it be suitable for this and if so how would you compare it to the butyl/foil products?


The MLV and butyl, in my estimation is the way to go. Like what SDS.com has


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## Ted White (May 19, 2009)

OldSchoolNewbie said:


> In home theater, there's more leighway to build a massive wall of layers. In cars, you're limited to about 1/2" in a lot of spots that you want to block sound.


There you go.


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## Ted White (May 19, 2009)

Rudeboy said:


> This seems "out there" to me and "apples and oranges".


That's not my website, however the data is correct. Concepts are correct.


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## timistim (Oct 13, 2008)

Just to throw something out there, seems to me that most of the noise in a car that you are trying to block out is not in the sub 100hz range. I understand that sub 100hz noise is being made by the speakers, but if that gets out does that really matter. Butyl should stop the panels from excessive vibration, and the MLV decoupled will stop the road noise from getting in. 

If I am wrong someone please tell me as this is the theory I am working with when I start my sound deadening project.


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## Rudeboy (Oct 16, 2005)

Ted White said:


> That's not my website, however the data is correct. Concepts are correct.


Let me be clear. I've never used Green Glue because there doesn't seem to be much application in a car because of the requirement that at least one of the sandwiching materials be air permeable. My impressions of the product have been favorable. It sounds like you have some relationship to the product, but now that isn't clear. That looks like Green Glue's Web site to me.

Te presentation I linked to has been discussed here before. Each sub panel may present correct data and concepts, but taken together the viewer is led to make certain conclusions about the efficacy of MLV vs. Green Glue. In the first place, since each represents a completely different approach to different problems, they aren't mutually exclusive. In the second, the MLV is used in sub-optimal arrangements. That's why I'm questioning it. To me it looks like putting up data about a person's need for water vs. air and stipulating that the water can only be used directly from the sea It just seems like an unnecessary comparison.


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## Rudeboy (Oct 16, 2005)

timistim said:


> Just to throw something out there, seems to me that most of the noise in a car that you are trying to block out is not in the sub 100hz range. I understand that sub 100hz noise is being made by the speakers, but if that gets out does that really matter. Butyl should stop the panels from excessive vibration, and the MLV decoupled will stop the road noise from getting in.
> 
> If I am wrong someone please tell me as this is the theory I am working with when I start my sound deadening project.


Just to be clear, butyl alone isn't going to deal the resonance - it has to be constrained, but your idea is correct. The point of this thread is to determine the role decoupling plays in a barrier's performance in our application. The assumption that it is critical has come from construction data where spaces are greater, existing barriers are more massive and the goal is to prevent voices from passing through walls. The notion of using a foam decoupling layers seems to fall in the same category as using multiple layers of CLD at 100% coverage - accepted wisdom that is wrong.

In my testing, I've found very similar results sandwiching steel/foam/MLV and steel/MLV/foam which suggests to me that the foam is just acting as a high frequency absorber - a good thing, but not a decoupler. The results get a little unclear around the resonant frequency of the steel panel. My tests are pretty crude and more study needs to be done. Nonetheless, vibration damper/barrier is the way to go - we're just investigating what 1/4" of foam between them accomplishes. 

I'm close to being convinced that the ideal application for the inner door skin is vibration damper/MLV/foam. The MLV replaces the vapor barrier and adds mass to the steel which already has a good airspace between it and the outer skin. The foam contributes to high frequency attenuation AND reduces rattles and buzzing of the door card that it would be in contact with.


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## timistim (Oct 13, 2008)

Rudeboy said:


> I'm close to being convinced that the ideal application for the inner door skin is vibration damper/MLV/foam.



Interesting suggestion here, used like this the MLV would not be decoupled, however you are suggesting that the decoupling is not doing that much in a car anyway. 

I will offer a different idea on how to use the MLV in a door, I would suggest that it would be best used on the outer skin. When used on the inner skin it would need to have holes in for mounting tabs, speakers, door arms and such. We know that MLV works best when the seams are sealed, on the outer door skin it would be easier to accomplish a layer of MLV that does not have holes then it would be on inner skin. Just a thought.


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## Ted White (May 19, 2009)

Rudeboy said:


> there doesn't seem to be much application in a car


There isn't. That's been my point all along. For many reasons including porous layers as you mentioned, heat, optimal damping at frequencies not relevent to your needs, etc.



Rudeboy said:


> That looks like Green Glue's Web site to me.


I think it is. That's not my website.



Rudeboy said:


> the MLV is used in sub-optimal arrangements.


That's not so. For construction applications MLV has been shown to perform nearly identically regardless of how it is inserted in the wall. Mass is mass. But this isn't a construction forum, and you aren't building walls.

MLV and similar panels seem to be the perfect product for your application. I came here to dispell any thoughts of Green Glue being used to damp panel resonance.


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## ANT (Oct 15, 2005)

Ted White said:


> I came here to dispell any thoughts of Green Glue being used to damp panel resonance.


 
Might you care to elaborate on your connection with the company so we know who we are getting our infomation from?


ANT


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## Rudeboy (Oct 16, 2005)

Ted White said:


> That's not so. For construction applications MLV has been shown to perform nearly identically regardless of how it is inserted in the wall. Mass is mass. But this isn't a construction forum, and you aren't building walls.


But inserting a layer of 1 lb/ft² MLV between two layers of drywall doesn't add much to the total mass/area of the package - that's what I mean by sub-optimal. Green Glue in the same configuration is performing a completely different function rendering the comparison silly, IMO.


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## Rudeboy (Oct 16, 2005)

timistim said:


> Interesting suggestion here, used like this the MLV would not be decoupled, however you are suggesting that the decoupling is not doing that much in a car anyway.
> 
> I will offer a different idea on how to use the MLV in a door, I would suggest that it would be best used on the outer skin. When used on the inner skin it would need to have holes in for mounting tabs, speakers, door arms and such. We know that MLV works best when the seams are sealed, on the outer door skin it would be easier to accomplish a layer of MLV that does not have holes then it would be on inner skin. Just a thought.


That's the theoretically ideal configuration for blocking sound, but unless you have a Saturn and can take the door panels off, installing a contiguous barrier on the exterior skin, working through the access holes gets old really fast - some vehicles more than others.

I'm just suggesting that you can get most of the barrier benefits while vapor sealing the door, isolating the front and back waves from door mounted speakers and a few other things, while making the job much easier. Unless somebody actually tests this, it's even possible to theorize that the barrier on the inner skin will be more effective since there is less opportunity for noise coming in through the sides of the door to bypass the barrier.


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## VP Electricity (Apr 11, 2009)

I am waiting for pics posted of a car with the exterior covered in MLV...


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## Rudeboy (Oct 16, 2005)

VP Electricity said:


> I am waiting for pics posted of a car with the exterior covered in MLV...


It's easier to wrap the passengers.


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## Ted White (May 19, 2009)

Rudeboy said:


> But inserting a layer of 1 lb/ft² MLV between two layers of drywall doesn't add much to the total mass/area of the package - that's what I mean by sub-optimal. Green Glue in the same configuration is performing a completely different function rendering the comparison silly, IMO.


I don't seek to argue. Sorry if it appears that way.

MLV is commonly recommended in constrained layer application as well as directly attached to the studs / joists. This recommendation comes from the few manufacturers as well as the distributors. 

My point was that the MLV tests the same regardless of its placement in a wall.

That is the direct comparison that all consumers are making... use MLV in my wall, or Green Glue, or something else in my wall. So it's proven to be the best / most useful comparison for contractors and consumers.

I was asked what my affiliation with Green Glue is. I'm not sure what the forum rules are here, as they differ by forum, so no ID in my signature to be safe. I am with "The Soundproofing Company". 

I was with the Green Glue Company since 2003. I have spent a few hundred hours over the years in independent labs watching materials being installed and tested. 

Soundproofing Company is the largest distributor of Green Glue, and I'm only here on this forum to tell you it won't work for autos for many reasons. Yes, I sell Green Glue and am telling you not to buy Green Glue.

Green Glue isn't optimized at all for autos.

I fear this thread has veered off course, and my apologies for that. Again, I'm looking to save auto aficionados the grief of the trial and error with a product that was meant for walls, not car doors.


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## timistim (Oct 13, 2008)

Rudeboy said:


> That's the theoretically ideal configuration for blocking sound, but unless you have a Saturn and can take the door panels off, installing a contiguous barrier on the exterior skin, working through the access holes gets old really fast - some vehicles more than others.
> 
> I'm just suggesting that you can get most of the barrier benefits while vapor sealing the door, isolating the front and back waves from door mounted speakers and a few other things, while making the job much easier. Unless somebody actually tests this, it's even possible to theorize that the barrier on the inner skin will be more effective since there is less opportunity for noise coming in through the sides of the door to bypass the barrier.



What is a day of installation if you don't do it in-efficantly and get scrapes and cuts on every part of your hands and/or arms, all in the name of doing it just a little bit better?


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## dbiegel (Oct 15, 2006)

FWIW, I sealed up all four of my door skin access holes with MLV about 8 months ago. In my car this was a relatively large (~12" by 6") hole in each door. I used the MLV to replace the flimsy factory plastic vapor barrier. The edges are triple sealed -- factory black crap + Liquid Nails HD + Damplifier Pro all the way around -- but I did not decouple it all, I left it as a limp mass.

Results? It seemed to make a huge difference in noise from the sides. The rest of my car is practically not deadened at all right now... so the best way I can describe it is that my car has pretty extreme structural noise (like road and engine noise) right now, but cars passing alongside of me are super quiet. There's still a ton of noise leaking in through the floor, firewall, rear wheel wells, and roof, but I feel confident that the doors are pretty much maxed out.

As for baffle results, I have to look at my old measurements to really compare. Right now I can tell you this much -- my mids measure mostly flat down to about 20hz (!), other than a 5db dip at their resonant frequency (~50hz) and the right side has a peak at 100hz. I'm sure part of that is from cabin gain, but thats quite remarkable for these 6.5" speakers (debucked 6w4311b).


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## dbiegel (Oct 15, 2006)

Ted White said:


> I was with the Green Glue Company since 2003. I have spent a few hundred hours over the years in independent labs watching materials being installed and tested.
> 
> Soundproofing Company is the largest distributor of Green Glue, and I'm only here on this forum to tell you it won't work for autos for many reasons. Yes, I sell Green Glue and am telling you not to buy Green Glue.
> 
> ...


Ted, I just wanted to say thanks for dropping in here and sharing your thoughts. In some ways, I feel like we car guys are still using a "shotgun approach" of relatively expensive and time consuming products and getting mediocre results. If you have any other tips, suggestions, or thoughts on how best to soundproof a vehicle, please share! We could really use your knowledge and expertise in this area as we're relying mostly on construction and theatre resources which may not apply to a car.


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## Ted White (May 19, 2009)

Thanks Dbiegel. I wish I could give a better answer but Rudeboy and DIYMA seem to have it covered


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## Rudeboy (Oct 16, 2005)

I ran some combinations through my "magic box" and here are the RTA results:








yellow = undamped steel
orange = undamped steel + 1 layer MLV
green = undamped steel + 1/4" CCF + MLV
purple = undamped steel + MLV + 1/4" CCF

The standard steel/CCF/MLV sandwich is clearly better for high frequencies. It looks like overall CCF is a worthwhile addition. I left several configurations out to keep things simple. If you are choosing between just CCF or MLV, go with MLV - much more effective. Replacing the CCF with a second layer of MLV does a better job up to 150 Hz but above that the advantage disappears.

I repeated the sequence using a fiberglass substrate instead of steel and the results were very similar except that there was almost no difference between CCF/MLV and MLV/CCF.


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## FoxPro5 (Feb 14, 2006)

dbiegel said:


> As for baffle results, I have to look at my old measurements to really compare. Right now I can tell you this much -- my mids measure mostly flat down to about 20hz (!), other than a 5db dip at their resonant frequency (~50hz) and the right side has a peak at 100hz. I'm sure part of that is from cabin gain, but thats quite remarkable for these 6.5" speakers (debucked 6w4311b).


Wish more would appreciate what you've done here. If you want excellent MB performance, the days of slapping a driver on an MDF ring, sealing up the access holes and throwing down a layer of "deadener" are over. A baffle is every part barrier as it is something to mount a speaker to.


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## Thewavecaraudio (Oct 20, 2007)

Interesting, now that I have decent damper products and some decent CCF i need now to find some MLV at a decent price here in Quebec, Canada


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## tspence73 (Oct 14, 2008)

FoxPro5 said:


> Wish more would appreciate what you've done here. If you want excellent MB performance, the days of slapping a driver on an MDF ring, sealing up the access holes and throwing down a layer of "deadener" are over. A baffle is every part barrier as it is something to mount a speaker to.


But, shouldn't there be *some* sound making it thru the baffle from the speaker's backwave? No speaker I've heard has a completely isolated backwave from inside the enclosure. I would think doing the deadener/foam/vinyl sandwich on the OUTTER door would be the way to go and on the INNER panel where the speaker mounts, do some deadener/seal the holes/foam/doorpanel. You could choose to either mount the speaker-pod to the door or you could even use the foam layer to de-couple the pod from the door metal (I decoupled my 8" mid-basses and I get no rattles now).


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## MiniVanMan (Jun 28, 2005)

tspence73 said:


> But, shouldn't there be *some* sound making it thru the baffle from the speaker's backwave? No speaker I've heard has a completely isolated backwave from inside the enclosure. I would think doing the deadener/foam/vinyl sandwich on the OUTTER door would be the way to go and on the INNER panel where the speaker mounts, do some deadener/seal the holes/foam/doorpanel. You could choose to either mount the speaker-pod to the door or you could even use the foam layer to de-couple the pod from the door metal (I decoupled my 8" mid-basses and I get no rattles now).


So, you can be lucid. 

Total isolation is extremely difficult and would require baffles that are very thick, and very dense. 

However, with what we're trying to accomplish, we're looking at "attenuating" the backwave. As long as we attenuate it enough, we will reduce the interference to inaudible. A good rule of thumb is 12 db of attenuation. The more the better of course.

This is where standard deadener fails. Look up how much deadener it would take to attenuate an 80 hz signal 12 db. You'll be surprised. Your door will probably fall off after applying the necessary amount.


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## tspence73 (Oct 14, 2008)

MiniVanMan said:


> So, you can be lucid.
> 
> Total isolation is extremely difficult and would require baffles that are very thick, and very dense.
> 
> ...


Yeah, don't forget you also have the CCF and the plastic door panel itself attenuating the backwave in conjunction with the deadener. Will MLV on the inner panel be worthwhile? Right now my CCF layer on my inner door is doing a great job of shielding my fiberglass/plastic inner panel from rattling along with partially decoupling my fiberglass midbass mounting pod.


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## capnxtreme (Feb 5, 2008)

Thin CCF (like what we use in the doors) will only attenuate high frequencies.

Like you mention, it's great for killing rattles, but it's not doing anything for midbass frequencies.

Great thread.


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## tspence73 (Oct 14, 2008)

capnxtreme said:


> Thin CCF (like what we use in the doors) will only attenuate high frequencies.
> 
> Like you mention, it's great for killing rattles, but it's not doing anything for midbass frequencies.
> 
> Great thread.


The plastic door panel then is the one last layer of separation for those frequencies. Okay, so I take it then the best thing to do is to use the deadener/foam/vinyl sammich for both the outter and inner door panels?


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## Rudeboy (Oct 16, 2005)

I've been getting really good results mounting MLV on the inner door skin with CCF mounted to the MLV in contact with the door card to control rattles. This configuration seems to work as well for blocking road noise as mounting the barrier to the exterior skin and it makes the inner skin a more effective baffle.


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## dbiegel (Oct 15, 2006)

Wouldn't we actually want the outer door skin (the panel facing the outside world) to block LESS than the inner door skin (the panel the speaker is mounted to)? After all, the inner skin is our actual speaker baffle. The outer is really just there to keep water out, make the car look pretty, and provide a cushion in an accident right?

My reasoning is that if the outer door skin is a super blocker, and the inner isn't, then the outer will just reflect MORE sound back in toward the cabin, which is the opposite of what we're trying to achieve (a solid baffle for the speaker, with as much backwave attenuation as possible).

Thoughts?


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## Rudeboy (Oct 16, 2005)

dbiegel said:


> Wouldn't we actually want the outer door skin (the panel facing the outside world) to block LESS than the inner door skin (the panel the speaker is mounted to)? After all, the inner skin is our actual speaker baffle. The outer is really just there to keep water out, make the car look pretty, and provide a cushion in an accident right?
> 
> My reasoning is that if the outer door skin is a super blocker, and the inner isn't, then the outer will just reflect MORE sound back in toward the cabin, which is the opposite of what we're trying to achieve (a solid baffle for the speaker, with as much backwave attenuation as possible).
> 
> Thoughts?


There are an awful lot of variables in this, so some good testing, I'd be reluctant to say placing the barrier on the exterior skin will make things worse. There are certainly arguments that can be made each way in terms of external noise attenuation and my guess there is that it probably varies a little bit each way depending on the vehicle. The baffle reinforcement idea makes sense to me. Placement on the exterior skin will reduce the amount of sounding that others can hear outside the car. Would a barrier on both the interior and exterior skins make things worse than just a barrier on the interior skin? Might be. The boundary behaviors of sound gets more complicated and at least for me, more difficult to create a valid mental picture for, the more complicated the system.

One thing is absolutely certain - it is MUCH easier in most vehicles to mount the barrier on the interior skin. It seems like a winner to me since it works so well in that configuration.


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## Thewavecaraudio (Oct 20, 2007)

What would be most effective config:

exterior skin door: damplifier
interior skin door: damplifier/CCF/MLV

rest of the car: damplifier/CCF/MLV

is that correct?


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## tspence73 (Oct 14, 2008)

Hmm,

Don. If you could do some testing it would be cool. I would think reducing the exterior noise more would be more preferable and hence a double sandwich of deadener/foam/vinyl for both the inner and outer panels. Especially since those doors are the closest panels to the outside of the car in respect to your ears. (That and the roof of the car). I figure any chance to double up noise reduction will improve results. The only question will be, will this hurt fidelity of the midbass? Don't know. Also, will this add too much weight to the door and cause issue with the hinge on the door long term?


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## Rudeboy (Oct 16, 2005)

tspence73 said:


> Hmm,
> 
> Don. If you could do some testing it would be cool. I would think reducing the exterior noise more would be more preferable and hence a double sandwich of deadener/foam/vinyl for both the inner and outer panels. Especially since those doors are the closest panels to the outside of the car in respect to your ears. (That and the roof of the car). I figure any chance to double up noise reduction will improve results. The only question will be, will this hurt fidelity of the midbass? Don't know. Also, will this add too much weight to the door and cause issue with the hinge on the door long term?


A meaningful test for this is beyond my capabilities. You also have to remember that the glass is always going to be a limiting factor. Adding barriers to both skins gets you very close, if not over that threshold. At a certain point, really good has to be good enough.

We are talking about 1/4" CCF and 1 lb/ft² MLV. I haven't been able to demonstrate a real difference between CCF then MLV vs. MLV then CCF. CCF against the sheet metal may add some vibration damping and may conform better to irregular surfaces, but other than that practical installation considerations seem more important.


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## tspence73 (Oct 14, 2008)

Rudeboy said:


> A meaningful test for this is beyond my capabilities. You also have to remember that the glass is always going to be a limiting factor. Adding barriers to both skins gets you very close, if not over that threshold. At a certain point, really good has to be good enough.


There is a security glass coating that I'm considering way down the road which claims to have a 3db to 4db reduction in external noise. It's an interesting idea, so maybe for that rare application an additional layer of noise reduction might be useful. But I see your point about diminishing returns beyond the inner panel.


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## FoxPro5 (Feb 14, 2006)

tspence73 said:


> Yeah, don't forget you also have the CCF and the plastic door panel itself attenuating the backwave in conjunction with the deadener.


Dammit, Spence quit talking out of your ass. Do you have CCF "attenuating" the backwave in your doors, or not? If you do, you're delusional once again. Stop reading and repeating, if not. CCF doesn't stop anything in that environment; it's just a bad idea (except for providing a minor air spring/mechanical isolator). ****in' Ensolite...burn the factory to the ground. 

I will agree with you about the efficacy of a damped decoupled barrier on the outside skin where it belongs. The goal of transmission loss is to stop sound as soon as possible and as close to the noise origin as possible to bend/refract as much low freq sound as possible. 

Does "deadener" really STOP the sheet metal in our cars from motion? Not if you put 10 layers of it down next to a high output driver like a 10" MB on a door panel. This is why it's very important to decouple that barrier..no matter where it is in the door...as it WILL be moving and WILL want to propagate sound. A moving barrier is a very bad thing. Why is lead such a good barrier? It's VERY hard to move, for starters. 

I have every popular "deadener" on the market...crap to awesome, CLD and liquids....lead, NHMC, barriers, wood, plastic, you name it in, on and around my front doors. And guess what? They STILL move. This is how I know these things.


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## FoxPro5 (Feb 14, 2006)

Thewavecaraudio said:


> What would be most effective config:
> 
> interior skin door: damplifier
> interior skin door: damplifier/CCF/MLV
> ...


Not to me. Sorry for the cocky attitude, but read what I just said. There's very effective and very smart; then there's monkey-see-monkey do half-ass attempts (albiet good natured and not totally stupid) like what's listed above. The solution depends on....
1) Your budget. Most don't want to spend any money on vibration and noise control
2) The actual, etiology of the problem (what's causing the issue you're trying to remedy)
3) Your system goals in terms of quiet and comfort, etc.

And I suppose a whole host of other factors as well. Bottom line, IMHO, is if you do what everyone else does, you're going to get get what everyone else usually gets: fairly satisfactory, not excellent results. I've been trying spread this message for 5 years, but it's becoming rhetoric and not enough seem to listen....so, I'm through.


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## ehiunno (Feb 26, 2008)

Dammit guys don't make foxpro leave again


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## falkenbd (Aug 16, 2008)

tspence73 said:


> There is a security glass coating that I'm considering way down the road which claims to have a 3db to 4db reduction in external noise. It's an interesting idea, so maybe for that rare application an additional layer of noise reduction might be useful. But I see your point about diminishing returns beyond the inner panel.


is the 3db to 4db reduction in noise over an open window?

because normal glass is greater than that

want to test it? play music outside your car and roll the window up and down...


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## ErinH (Feb 14, 2007)

I'm going to put thin set in my entire car.

eff all your 'foam' and 'mlv'.

BAM!


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## falkenbd (Aug 16, 2008)

bikinpunk said:


> I'm going to put thin set in my entire car.
> 
> eff all your 'foam' and 'mlv'.
> 
> BAM!


just make sure you use some sort of mesh in it, otherwise it'll crack and crumble


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## captainobvious (Mar 11, 2006)

Seems to me that there is so much noise penetration from other areas that going overboard in the doors becomes a war of attrition.

If your talking about panel resonance, those things can be contained. But if your goal is to kill noise from penetrating the cabin from the outside, thats a whole different animal.
There seems to be so much penetration from wheel wells, windows/glass, door jams, firewall...etc. 
Its just seems to me at least that their isnt really a viable solution for this when considering the space limitations and the fact that you have to be able to "see" while driving. You may be able to make it _slightly_ better, but at what cost?


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## ErinH (Feb 14, 2007)

falkenbd said:


> just make sure you use some sort of mesh in it, otherwise it'll crack and crumble


lol. that might actually work! the car would be built like a friggin tank, man! 

we'll have to get someone on the forum to be the guinea pig. *not it*


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## captainobvious (Mar 11, 2006)

bikinpunk said:


> I'm going to put thin set in my entire car.
> 
> eff all your 'foam' and 'mlv'.
> 
> BAM!



Just lay down a ****LOAD of non hardening modeling clay loaded with lead shot


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## Thewavecaraudio (Oct 20, 2007)

FoxPro5 said:


> Not to me. Sorry for the cocky attitude, but read what I just said. There's very effective and very smart; then there's monkey-see-monkey do half-ass attempts (albiet good natured and not totally stupid) like what's listed above. The solution depends on....
> 
> It is allright for the attitude. You are lucky I undertstand half of the expression you wrote (vive les canadien français , good for me I guess
> 
> ...




*Question is wiht the stuff I have, what is the best way to use the products I have there and do the best job I can with that. I guess there is maybe better way (concret car) or I don't know but I guess I can do something good with that maybe best than average. Just want to do it the best way possible. I'm far from being a pro of acoustic so this is why I read and ask question.*




> is if you do what everyone else does, you're going to get get what everyone else usually gets:


Up here don't know lots of people using damp + CCF + MLV and even on this forum haven't seen a lot people talking about it. A little bit there and here but there is lot of opinions so I'm asking again 

My idea is for now

Major parts of the car with Damplifer pro + eDeadV3 for hard reaching parts + CCF + MLV. 

Place I won't be able to put all 3 because of thickness it will be damplifer first + MLV is there is some place


So that's about it. if You need more info on my goal or objectives or where I am going with that let me know


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## Rudeboy (Oct 16, 2005)

Thewavecaraudio said:


> *Question is wiht the stuff I have, what is the best way to use the products I have there and do the best job I can with that. I guess there is maybe better way (concret car) or I don't know but I guess I can do something good with that maybe best than average. Just want to do it the best way possible. I'm far from being a pro of acoustic so this is why I read and ask question.*
> 
> 
> 
> ...


I'd leave the liquid out of the mix - if you can't get to it with the Damp Pro it doesn't need to be got  Other than that you plan sounds good.


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## Thewavecaraudio (Oct 20, 2007)

Mayeb little publicity the CCF will be some ensolite 

but thanks for your clues and opinions...

I'm pretty sure this thread will be usefull for ohter people that are not pros like me...


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