Sound Dampening information
07-01-07, 09:48 PM
#76
Quiet Car Spray On Solution
You guys should really consider a spray on alternative to the mats, Quiet Car (http://www.quietcoat.com/)
I did an entire write up of the project awhile ago:
https://www.rx7club.com/showthread.ph...ght=quiet+coat
Weight is about 40lbs. for the entire car (much less than the mats) - doors, hood, trunk, and undercoating. I achieved a 13 dba reduction which I understand is huge. Here is a graph of the results:
I did an entire write up of the project awhile ago:
https://www.rx7club.com/showthread.ph...ght=quiet+coat
Weight is about 40lbs. for the entire car (much less than the mats) - doors, hood, trunk, and undercoating. I achieved a 13 dba reduction which I understand is huge. Here is a graph of the results:
08-05-07, 09:19 PM
#78
Dynamat in my 93
Good info in this thread. Thanks Rynberg for the info on a- and c-weighted sound measurements.
A while ago I "Dynamatted" my FD to help bring the exhaust noise levels down. I wasn't expecting a dramatic difference, but I wanted to hear the difference.
Although I don't have the equipment to perform before and after sound level analyses, I can describe my old Mazda after the project as providing a somewhat more "civil" driving experience.
The exhaust noise level is reduced enough to notice a difference, and that's about it. But it IS a difference.
And although it wasn't really noisy to begin with, there is less suspension noise coming from the RX7.com Traction/Drag Launch kit. Given the car has some factory sound deadening material behind the seats indicates the original designers too felt that noise could be eliminated by putting something there, and the DE further helped quiet that area.
It was a good amount of work, as I laid all the pieces by hand, but I wanted it to look a certain way.
I put down one layer of Dynamat Extreme over the trunk floor, with two layers over the areas immediately above the exhaust outlet. I covered the exhaust heat shield with four layers of DE.
On top of the Dynamat I have a 3/4" sheet of what looks like a thick roll of dryer lint, which I purchased from OSH. On top of that I have a thin rubber sheet, also purchased from OSH, then there's the carpet on top.
The whole idea was to have different materials working together to absorb different frequencies.
In the pics can be see the Dynamatted heat shield and various photos of the rear half my car.
I drive my FD every day, and I really just wanted it a little more civilized.
If anything, the car's definitely a lot shinier.
juicy
A while ago I "Dynamatted" my FD to help bring the exhaust noise levels down. I wasn't expecting a dramatic difference, but I wanted to hear the difference.
Although I don't have the equipment to perform before and after sound level analyses, I can describe my old Mazda after the project as providing a somewhat more "civil" driving experience.
The exhaust noise level is reduced enough to notice a difference, and that's about it. But it IS a difference.
And although it wasn't really noisy to begin with, there is less suspension noise coming from the RX7.com Traction/Drag Launch kit. Given the car has some factory sound deadening material behind the seats indicates the original designers too felt that noise could be eliminated by putting something there, and the DE further helped quiet that area.
It was a good amount of work, as I laid all the pieces by hand, but I wanted it to look a certain way.
I put down one layer of Dynamat Extreme over the trunk floor, with two layers over the areas immediately above the exhaust outlet. I covered the exhaust heat shield with four layers of DE.
On top of the Dynamat I have a 3/4" sheet of what looks like a thick roll of dryer lint, which I purchased from OSH. On top of that I have a thin rubber sheet, also purchased from OSH, then there's the carpet on top.
The whole idea was to have different materials working together to absorb different frequencies.
In the pics can be see the Dynamatted heat shield and various photos of the rear half my car.
I drive my FD every day, and I really just wanted it a little more civilized.
If anything, the car's definitely a lot shinier.
juicy
Um.. Yeah...
08-09-07, 03:25 AM
#85
"Xtreme" Dynamat is a thinner version of the "regular" flavor.
The majority of it is only 1 layer.
The lint rug and the rubber sheet: 5lbs probably ?
i didn't feel it was necessary to weight it on a scale, but the entire sound deadening sandwich definitely weighs less than the long-gone Bose caterpillar.
i chose the Dynamat method because i haven't been satisfied with liquid techniques (YMMV). i DO use the spray-on sound insulation on the inside of speaker enclosures because they bond to the porous MDF very well and do reduce the boxes' resonances, aside from completely sealing the wood.
Applied to a clean trunk floor, Dynamat will never lose it's adhesion, vibrate loose off the car's painted panels or chip off over time in the FD's environment. Plus with Dynamat, there's no guessing how thick a layer is.
But like any modification, the quality of the installation is a big part of the effectiveness of the installation. And i wanted it to look good and finish the job without ever wishing i had done it differently or ever think about redoing it.
It's difficult to convey how much something sounds quieter without actually hearing [it] before and after the sound deadening. If i said 2-1/2 dB, most people wouldn't be able to really gauge the difference. Given that, there's a difference between 2 db drop from 60dB and 2dB reduction from 90dB.
But i can *describe* that the center "stage" of the sound has shifted forward - from the rear of the car more toward the front of the car; my turbo's spooling and my BOV purge both sound louder than before, even though i hadn't made any changes under the hood. That made me happy.
My old Mazda will never be as quiet as an Infiniti ...but it IS quieter.
juicy
The majority of it is only 1 layer.
The lint rug and the rubber sheet: 5lbs probably ?
i didn't feel it was necessary to weight it on a scale, but the entire sound deadening sandwich definitely weighs less than the long-gone Bose caterpillar.
i chose the Dynamat method because i haven't been satisfied with liquid techniques (YMMV). i DO use the spray-on sound insulation on the inside of speaker enclosures because they bond to the porous MDF very well and do reduce the boxes' resonances, aside from completely sealing the wood.
Applied to a clean trunk floor, Dynamat will never lose it's adhesion, vibrate loose off the car's painted panels or chip off over time in the FD's environment. Plus with Dynamat, there's no guessing how thick a layer is.
But like any modification, the quality of the installation is a big part of the effectiveness of the installation. And i wanted it to look good and finish the job without ever wishing i had done it differently or ever think about redoing it.
It's difficult to convey how much something sounds quieter without actually hearing [it] before and after the sound deadening. If i said 2-1/2 dB, most people wouldn't be able to really gauge the difference. Given that, there's a difference between 2 db drop from 60dB and 2dB reduction from 90dB.
But i can *describe* that the center "stage" of the sound has shifted forward - from the rear of the car more toward the front of the car; my turbo's spooling and my BOV purge both sound louder than before, even though i hadn't made any changes under the hood. That made me happy.
My old Mazda will never be as quiet as an Infiniti ...but it IS quieter.
juicy
08-09-07, 08:36 AM
#86
i chose the Dynamat method because i haven't been satisfied with liquid techniques (YMMV). i DO use the spray-on sound insulation on the inside of speaker enclosures because they bond to the porous MDF very well and do reduce the boxes' resonances, aside from completely sealing the wood.
"What is QuietCar?
QuietCar is a sound and vibration control product based on new high-tech materials science leveraging the viscoelastic properties of newly developed polymer. The technology behind QuietCar is a viscoelastic water-based polymer which converts kinetic energy (noise) into miniscule amounts of heat energy. Following the basic law of energy conservation, the kinetic energy is eliminated, and so is noise.
How does QuietCar work?
The easiest way to learn more about QuietCar products is to understand what makes sound. Sound is just a disturbance in the air caused by vibration. When the air vibrates, your ears interpret it as sound. So basically, it takes something moving or vibrating to make a sound.
QuietCar is made to stop structure-borne noises. In cars, this means vibrations in the body panels, the engine, the suspension, the A/C system and so on. With all these unwanted vibrations in check, the vehicle is much quieter on the freeway. The old way of removing unwanted noise was to add heavy asphalt mats to the body metal. What these heavy mats do is add mass to the body panel, often as much as the panel itself. This doesn’t remove the vibration, it just lowers the intensity. The problem vibration is still there. Remember sound is logarithmic. So if you added twice the weight to the panel, it wouldn’t remove half the sound, only enough that you could just hear it. You would have to add lots of weight to get rid of half the noise.
Instead of being a Band-Aid and trying to cover up the sound, QuietCar works like a cure for the vibration problem. It actually gets rid of the vibration by converting it into low-grade heat. The back and forth vibrations, or mechanical energy, are converted to thermal energy or heat. However, it would take a thermometer that could read down to 0.001 degrees to see it.QuietCar is a high-tech polymer that absorbs twice as much noise & vibration as old techniques such as asphalt, rubber and elastomer coatings.
Comparing QuietCar to Mats
QuietCar, on average, is less expensive, less weight, and takes less time to apply than mats. With QuietCar, significant noise reduction can be achieved without removing the seats and carpeting. Just and undercoat and wheel wells can have a significant impact. Moreover, QuietCar absorbs the actual noise and vibrations across a wide frequency range, rather than just mask it or try to shift the frequencies. QuietCar literally absorbs the energy, and this is a key difference between QuietCar and other products. With QuietCar, even if you don’t get every nook and cranny, vibration is absorbed and dissipated nevertheless. So QuietCar is easy to use.
QuietCar is often applied to trunks for installation of subwoofers. QuietCar can cover the interior of a trunk with approximately 1 gallon, and provides approximately 2 times the noise and vibration dampening of mats (see chart below).
01-09-08, 10:27 AM
#87
Aloha Icemark, Play Well.
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Great thread. Old, but great.
Try here for the text of the original page without pictures:
http://web.archive.org/web/*/http://...unddampen.html
Try here for the text of the original page without pictures:
http://web.archive.org/web/*/http://...unddampen.html
06-23-08, 07:15 PM
#90
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I haven't read every post in this thread, but thought I would post results of my sound damping efforts using Fatmat bulk roll on my previous car - an 02 WRX Wagon. In the WRX, the majority of the road noise is from engine noise and wind noise. I wanted to make it quieter, so I stripped the entire interior out except for the head liner. I put the fatmat on every single square inch of surface that I could possible do, including the inside and oustide door skins and the hatch.
Install was pretty easy since it's peel and stick. Only down side was that it made the carpet not fit as well, but it wasn't very noticeable.
Before Fatmat:
Parked, idling: 45 dB
Parked, 3,000 rpm: 58 dB
70 mph, 5th gear, concrete interstate: 75 dB
35 mph, 3rd gear, asphalt street: 65 dB
After Fatmat:
Parked, idling: 45 dB
Parked, 3,000 rpm: 57 dB
70 mph, 5th gear, concrete interstate: 72 dB
35 mph, 3rd gear, asphalt street: 64 dB
Measurements were taken using my friend's sound meter from work, calibrated the morning of the first test (before Fatmat), and driving on the same stretch of interstate and street, in the same lanes, with no surrounding traffic, on dry, non-windy days, with the radio and heater turned off.
Conclusions: at idle, the only noise you hear is engine noise, which isn't affected by Fatmat installed in the doors and floor (stating the obvious, I know). At highway speed, there is a small but noticeable decrease in road noise. It didn't do anything for engine noise since I couldn't reach the fire wall to cover it in fatmat.
Was it worth the $100 plus 8 hours labor to strip the interior and put it back together? Eh, I guess so.
Install was pretty easy since it's peel and stick. Only down side was that it made the carpet not fit as well, but it wasn't very noticeable.
Before Fatmat:
Parked, idling: 45 dB
Parked, 3,000 rpm: 58 dB
70 mph, 5th gear, concrete interstate: 75 dB
35 mph, 3rd gear, asphalt street: 65 dB
After Fatmat:
Parked, idling: 45 dB
Parked, 3,000 rpm: 57 dB
70 mph, 5th gear, concrete interstate: 72 dB
35 mph, 3rd gear, asphalt street: 64 dB
Measurements were taken using my friend's sound meter from work, calibrated the morning of the first test (before Fatmat), and driving on the same stretch of interstate and street, in the same lanes, with no surrounding traffic, on dry, non-windy days, with the radio and heater turned off.
Conclusions: at idle, the only noise you hear is engine noise, which isn't affected by Fatmat installed in the doors and floor (stating the obvious, I know). At highway speed, there is a small but noticeable decrease in road noise. It didn't do anything for engine noise since I couldn't reach the fire wall to cover it in fatmat.
Was it worth the $100 plus 8 hours labor to strip the interior and put it back together? Eh, I guess so.
06-25-08, 03:57 PM
#92
Diamond Cut Seven
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The best product out is Q-mat by far. I have compared it to other thickness, Benz & Bimmer both use it. I have it on my FD and it definitely killed the droning a lot.
It is $$ but damn worth it! http://thermalsound.com/products.asp?cat=15
It is $$ but damn worth it! http://thermalsound.com/products.asp?cat=15
06-26-08, 01:49 PM
#93
The best product out is Q-mat by far. I have compared it to other thickness, Benz & Bimmer both use it. I have it on my FD and it definitely killed the droning a lot.
It is $$ but damn worth it! http://thermalsound.com/products.asp?cat=15
It is $$ but damn worth it! http://thermalsound.com/products.asp?cat=15
06-27-08, 07:24 AM
#94
Like David, I used the Quiet Car spray and brush on products. There are still places where matting works, but spray on deadeners directly effect the vibration in the metal itself. Mats cannot do that. You want to use matting on the inside of the door panel, but spray on deadening on the metal exterior of the doors. Spraying parts of the undercarriage and firewall also helps.
Gordon
Gordon
07-06-08, 11:14 PM
#95
Yellow Dragon is no more
Thread Starter
WOW ... still can't believe this thread lives.
If anyone wants the original pics or wants to host the original web page, just let me know.
If anyone wants the original pics or wants to host the original web page, just let me know.
09-07-09, 12:52 AM
#97
Ex-EPiK Rotary Doode
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This question has been asked before in this thread, but I didn't see anything resembling a useful answer, so I'll try to ask it properly.
Does anyone have good estimates on the interior passenger space of the FC and the FD for sound deadening purposes? They can be rough estimates...
For example since I've got more experience with the FC, I've been trying to make an educated guess. From Mazda's published promotional literature, the interior cargo volume of the hatch was 6.5 cubic feet... so that could lead to a general guestimate of about 18 sq ft for the hatch area.
I'm trying to put together a restoration budget for each car for a future project, but I don't have either of the cars handy to take any measurements myself.
Anyone have rough figures for the doors, firewall, floors and roof? Right now I'd even take a rough passenger space volume figure. From a cost and wieght perspective, having some good estimates of the coverage areas will go a long way in the planning and budgeting.
My only other comment on this thread. I strongly agree with what's been said about the lack of effectiveness of asphault mass loaders... in order to be effective, you have to add a whole lot of weight to the car, use multiple layers, and on a hot day, your car smells like a fresh paved road unless you use some form of sealant on top of the stuff.
I don't agree with what's been said about one form of deadening working better than any others. Though liquid deadeners are effective and can be effective on their own, to achieve the best results, a combination of products is necessary since each product is designed to handle a different tasks. Some are vibration absorbers, some are resonence killers, some reflect high frequencies, some block/absorb lower frequencies.
In my experience, the best results are accomplished with a use of:
1) A butyl/aluminum mat product (Damplifer, Dynamat Extreme, Raammat) These are not mass loader products, but absorb vibrations and convert them to heat which is radiated by the aluminum surface, which also reflects higher frequency sounds.
2) Then using a viscoelastic liquid deadener product (like Second Skin's Spectrum and Quiet Coat). Though this works similarly to the way the mat does, it works against different frequencies and can be used to get into areas that the mat cannot practically be used.
3)Finally, using a foam-based blocker compound product like Second Skin's Luxury Liner and Overkill. Luxury Liner is thick and heavy, but absorbs/blocks a large frequency range. Overkill is a thinner closed cell foam that works well against high frequencies. Overkill and Luxury Liner don't really need to be combined in the same location, but with the weight of Luxury Liner, and the fact that the RX-7 is a sports car, you want to pick and choose the worst areas of noise transmission like the wheel wells, firewall and transmission tunnels for using it, and then use the lighter weight Overkill in the rest of the spots.
Overall I'm a supporter of Second Skin products, I've been aware of and using their products for a few years now. It was no suprise that they won the Sound Deadener Showdown. They are constantly adding new products to their lineup, and improving their existing products, and their staff are all enthusiasts and they offer some of the best customer support in the business.
Since this is a sticky on sound deadening, I figured that this was some good information to be added.
Does anyone have good estimates on the interior passenger space of the FC and the FD for sound deadening purposes? They can be rough estimates...
For example since I've got more experience with the FC, I've been trying to make an educated guess. From Mazda's published promotional literature, the interior cargo volume of the hatch was 6.5 cubic feet... so that could lead to a general guestimate of about 18 sq ft for the hatch area.
I'm trying to put together a restoration budget for each car for a future project, but I don't have either of the cars handy to take any measurements myself.
Anyone have rough figures for the doors, firewall, floors and roof? Right now I'd even take a rough passenger space volume figure. From a cost and wieght perspective, having some good estimates of the coverage areas will go a long way in the planning and budgeting.
My only other comment on this thread. I strongly agree with what's been said about the lack of effectiveness of asphault mass loaders... in order to be effective, you have to add a whole lot of weight to the car, use multiple layers, and on a hot day, your car smells like a fresh paved road unless you use some form of sealant on top of the stuff.
I don't agree with what's been said about one form of deadening working better than any others. Though liquid deadeners are effective and can be effective on their own, to achieve the best results, a combination of products is necessary since each product is designed to handle a different tasks. Some are vibration absorbers, some are resonence killers, some reflect high frequencies, some block/absorb lower frequencies.
In my experience, the best results are accomplished with a use of:
1) A butyl/aluminum mat product (Damplifer, Dynamat Extreme, Raammat) These are not mass loader products, but absorb vibrations and convert them to heat which is radiated by the aluminum surface, which also reflects higher frequency sounds.
2) Then using a viscoelastic liquid deadener product (like Second Skin's Spectrum and Quiet Coat). Though this works similarly to the way the mat does, it works against different frequencies and can be used to get into areas that the mat cannot practically be used.
3)Finally, using a foam-based blocker compound product like Second Skin's Luxury Liner and Overkill. Luxury Liner is thick and heavy, but absorbs/blocks a large frequency range. Overkill is a thinner closed cell foam that works well against high frequencies. Overkill and Luxury Liner don't really need to be combined in the same location, but with the weight of Luxury Liner, and the fact that the RX-7 is a sports car, you want to pick and choose the worst areas of noise transmission like the wheel wells, firewall and transmission tunnels for using it, and then use the lighter weight Overkill in the rest of the spots.
Overall I'm a supporter of Second Skin products, I've been aware of and using their products for a few years now. It was no suprise that they won the Sound Deadener Showdown. They are constantly adding new products to their lineup, and improving their existing products, and their staff are all enthusiasts and they offer some of the best customer support in the business.
Since this is a sticky on sound deadening, I figured that this was some good information to be added.
10-24-09, 04:11 PM
#98
I think when I get my interior painted and the lighting all finished I'm going to start my audio rework project. This will mean 6 1/2 components up front, same speakers in back, new amps, and new 12 subwoofer. So while I do this I think I'm going to go the "combination" route.
Quiet Coat on the trunk area, doors, bin area, wheel well area, and entire floor. Then add B-Quiet to the trunk.
I think the B-Quiet (matting) will help to eliminate more of the rattling you get from a subwoofer and make some tighter bass. I might add some B-Quiet behind the rear speakers as well.
Quiet Coat on the trunk area, doors, bin area, wheel well area, and entire floor. Then add B-Quiet to the trunk.
I think the B-Quiet (matting) will help to eliminate more of the rattling you get from a subwoofer and make some tighter bass. I might add some B-Quiet behind the rear speakers as well.
10-24-09, 11:31 PM
#99
I think when I get my interior painted and the lighting all finished I'm going to start my audio rework project. This will mean 6 1/2 components up front, same speakers in back, new amps, and new 12 subwoofer. So while I do this I think I'm going to go the "combination" route.
Quiet Coat on the trunk area, doors, bin area, wheel well area, and entire floor. Then add B-Quiet to the trunk.
I think the B-Quiet (matting) will help to eliminate more of the rattling you get from a subwoofer and make some tighter bass. I might add some B-Quiet behind the rear speakers as well.
Quiet Coat on the trunk area, doors, bin area, wheel well area, and entire floor. Then add B-Quiet to the trunk.
I think the B-Quiet (matting) will help to eliminate more of the rattling you get from a subwoofer and make some tighter bass. I might add some B-Quiet behind the rear speakers as well.
10-25-09, 12:22 AM
#100
You still glad you used the quiet coat? My car is really loud and I always have my music cranked up. I'm looking to make it sound more luxurious (modern) on the inside when my music isn't playing and when I am rocking out have everything sound tighter and less tingy.