Sound Deadening 101
02-22-2007, 10:48 AM
#1
Team Owner
Thread Starter
Sound Deadening 101
Sound Deadening 101
I'm posting this in order to help first timers, and maybe clear up some of the fog around sound deadening in general.
First, I want to make clear the differences between damping material and sound barrier material.
A quick definition:
Damping material reduces vibration on panels where it is applied. A sound barrier material acts to reduce outside noise.
What is damping?
The main idea behind damping a panel is to reduce its tendency to vibrate. A panel may vibrate and create noise, or it may result in distortion of sound. ie: If the panel with the speaker installed vibrates.
How does it work?
How damping works is simple - The more mass a panel has, the less likely it is to vibrate. Also, this lowers the resonant frequency. The more mass, the better.
Why do it?
This can greatly reduce the possibility of a panel buzzing. Particularly, door panels. Also, if a car's body panel is over your exhaust system, it could be resonating and creating interior noise. The less of your car flexing and vibrating when your sound system is playing, the better. Midbass can be increased with door applications.
Where to do it?
There is one place it should always be done: The door panel. Particularly behind the speaker, and on the surface of the panel. Aside from that: Anywhere that resonates. Tap your panels fairly hard. If they go pong! then deaden them until they go thud. If you want to save weight and money, don't bother deadening panels that already go thud. A good example in the C5 is most of the center tunnel, and the floor under the seats. I personally like to deaden the thin plastic interior panels as well. Doing this in my door panel reduced some midbass distortion I was getting.
What materials are available?
Butyl
Butyl is the best possible material for damping sheets. It's easy to cut, easy to work with. Generally does not require a heat gun, or any special considerations to install it. Butyl is also very likely to stay stuck where you put it.
Vinyl
While better than Asphalt, Vinyl still is somewhat harder to work with than butyl.
Asphalt
Asphalt is the 'old' way to do it. It's messier, can sometimes have an odor, and very possibly may lose adhesion. I would suggest steering clear of any asphalt sheets.
Liquid
Liquid has been gaining popularity, and I use it myself as a base layer. You have the advantage of being able to vary the thickness according to the shape of the panel, and you won't waste any material trying to wrap it around corners, or get it in tight spaces. The disadvantage to liquid is the time it takes to fully cure. Most take 24 hours at room temperature. And up to a week if you are like me and can't wait for summer.
What are the costs?
Cost can vary tremendously. My suggestion is to go with the thickest, cheapest, butyl mat available at the time. Right now, I believe that is Edead from Elemental Designs. Aside from that, you can get the material as cheap as $1 a square foot, $5 a square foot, and even more if you buy brands like Dynamat.
What doesn't it do?
Damping does not do much to filter out outside noise, or road noise. If you are applying damper to simply reduce road noise, you are wasting your money. And this brings us to the next half of the thread:
Killing Sound with a sound barrier
What is a sound barrier?
A type of material designed to reduce or reflect the sound that passes through it. A reduction of sound transmission.
Why do it?
You are looking to reduce road noise, or outside noise entering the car. Foam can also be used to reduce rattles, when stuffed in a rattle prone panel.
Where to do it?
The factory is pretty smart when it comes to this. Look for where they have added foam, and back it up with more foam. This foam is useful just about anywhere, but I'd start with the floorboards, over the wheel wells, and the back walls. Behind the engine (interior of course) and lastly, doors. In my install, I attached foam to the back of all plastic trim panels.
What materials are available?
Closed Cell Neoprene Foam
Available in 1/8 or 1/4 from various sound deadening suppliers. This material is very easy to work with, stretches easily, and tears when you want it to. It's somewhat compressible. The greatest advantage is that it should not mold, which is a concern with open cell foam, especially in the doors. FWIW, most factory cars use open cell foam.
Frost King
I believe Frost King is an open cell foam, and it is foil backed, and self adhesive. It is fairly easy to work with, though much more difficult than the neoprene sheets because of the foil backing. It is slightly less than 1/8" thick, and much less dense than closed cell neoprene. Frost King offers much less sound insulation than the other foam, but the foil layer does help against heat.
Composite Materials
There are a few materials available, at a much higher cost, which are gneerally very thick and are built as such: Foam - Vinyl - Foam. Or Foam - Lead - Foam. These tend to be the heaviest as well, but also the most effective.
What are the costs?
Frost King is about $1/ft^3. Neoprene is anywhere from $1-5 on up depending on thickness. RAAM Audio is the least expensive, and I would highly suggest buying 1/8 foam because of its flexibility, and then doubling up in areas where you can.
What doesn't it do?
From my basic testing (Using various materials as a sound barrier VS a speaker in a box playing pink noise, measured with my RTA) this thickness of foam does not make a massive difference. Most of the sound reduction is at frequencies over 1k. So for road noise below 1k, don't expect a big difference. This should help with tire noise fairly well though. Also, foam does not dampen a panel, please use damping under the foam in places you need to.
Hope this helps.
Weak Points in the C5
Now that I've got my Ensolite install complete, I'd like to point out a few places that will give you a nice improvement with foam. - Attach foam to the back of the B pillar trim panels. There is no factory sound insulation here. Not a lot of sound gets through here, but its right on top of your ear. One layer of 1/8 did perfectly for me.
Behind the seats, on the back wall. Put in as much as you can.
I'm posting this in order to help first timers, and maybe clear up some of the fog around sound deadening in general.
First, I want to make clear the differences between damping material and sound barrier material.
A quick definition:
Damping material reduces vibration on panels where it is applied. A sound barrier material acts to reduce outside noise.
What is damping?
The main idea behind damping a panel is to reduce its tendency to vibrate. A panel may vibrate and create noise, or it may result in distortion of sound. ie: If the panel with the speaker installed vibrates.
How does it work?
How damping works is simple - The more mass a panel has, the less likely it is to vibrate. Also, this lowers the resonant frequency. The more mass, the better.
Why do it?
This can greatly reduce the possibility of a panel buzzing. Particularly, door panels. Also, if a car's body panel is over your exhaust system, it could be resonating and creating interior noise. The less of your car flexing and vibrating when your sound system is playing, the better. Midbass can be increased with door applications.
Where to do it?
There is one place it should always be done: The door panel. Particularly behind the speaker, and on the surface of the panel. Aside from that: Anywhere that resonates. Tap your panels fairly hard. If they go pong! then deaden them until they go thud. If you want to save weight and money, don't bother deadening panels that already go thud. A good example in the C5 is most of the center tunnel, and the floor under the seats. I personally like to deaden the thin plastic interior panels as well. Doing this in my door panel reduced some midbass distortion I was getting.
What materials are available?
Butyl
Butyl is the best possible material for damping sheets. It's easy to cut, easy to work with. Generally does not require a heat gun, or any special considerations to install it. Butyl is also very likely to stay stuck where you put it.
Vinyl
While better than Asphalt, Vinyl still is somewhat harder to work with than butyl.
Asphalt
Asphalt is the 'old' way to do it. It's messier, can sometimes have an odor, and very possibly may lose adhesion. I would suggest steering clear of any asphalt sheets.
Liquid
Liquid has been gaining popularity, and I use it myself as a base layer. You have the advantage of being able to vary the thickness according to the shape of the panel, and you won't waste any material trying to wrap it around corners, or get it in tight spaces. The disadvantage to liquid is the time it takes to fully cure. Most take 24 hours at room temperature. And up to a week if you are like me and can't wait for summer.
What are the costs?
Cost can vary tremendously. My suggestion is to go with the thickest, cheapest, butyl mat available at the time. Right now, I believe that is Edead from Elemental Designs. Aside from that, you can get the material as cheap as $1 a square foot, $5 a square foot, and even more if you buy brands like Dynamat.
What doesn't it do?
Damping does not do much to filter out outside noise, or road noise. If you are applying damper to simply reduce road noise, you are wasting your money. And this brings us to the next half of the thread:
Killing Sound with a sound barrier
What is a sound barrier?
A type of material designed to reduce or reflect the sound that passes through it. A reduction of sound transmission.
Why do it?
You are looking to reduce road noise, or outside noise entering the car. Foam can also be used to reduce rattles, when stuffed in a rattle prone panel.
Where to do it?
The factory is pretty smart when it comes to this. Look for where they have added foam, and back it up with more foam. This foam is useful just about anywhere, but I'd start with the floorboards, over the wheel wells, and the back walls. Behind the engine (interior of course) and lastly, doors. In my install, I attached foam to the back of all plastic trim panels.
What materials are available?
Closed Cell Neoprene Foam
Available in 1/8 or 1/4 from various sound deadening suppliers. This material is very easy to work with, stretches easily, and tears when you want it to. It's somewhat compressible. The greatest advantage is that it should not mold, which is a concern with open cell foam, especially in the doors. FWIW, most factory cars use open cell foam.
Frost King
I believe Frost King is an open cell foam, and it is foil backed, and self adhesive. It is fairly easy to work with, though much more difficult than the neoprene sheets because of the foil backing. It is slightly less than 1/8" thick, and much less dense than closed cell neoprene. Frost King offers much less sound insulation than the other foam, but the foil layer does help against heat.
Composite Materials
There are a few materials available, at a much higher cost, which are gneerally very thick and are built as such: Foam - Vinyl - Foam. Or Foam - Lead - Foam. These tend to be the heaviest as well, but also the most effective.
What are the costs?
Frost King is about $1/ft^3. Neoprene is anywhere from $1-5 on up depending on thickness. RAAM Audio is the least expensive, and I would highly suggest buying 1/8 foam because of its flexibility, and then doubling up in areas where you can.
What doesn't it do?
From my basic testing (Using various materials as a sound barrier VS a speaker in a box playing pink noise, measured with my RTA) this thickness of foam does not make a massive difference. Most of the sound reduction is at frequencies over 1k. So for road noise below 1k, don't expect a big difference. This should help with tire noise fairly well though. Also, foam does not dampen a panel, please use damping under the foam in places you need to.
Hope this helps.
Weak Points in the C5
Now that I've got my Ensolite install complete, I'd like to point out a few places that will give you a nice improvement with foam. - Attach foam to the back of the B pillar trim panels. There is no factory sound insulation here. Not a lot of sound gets through here, but its right on top of your ear. One layer of 1/8 did perfectly for me.
Behind the seats, on the back wall. Put in as much as you can.
Last edited by Kale; 02-23-2007 at 10:37 AM.
02-22-2007, 11:44 AM
#4
Race Director
So what is the crappy Green Yarn looking type stuff in the C4 vettes that they use as a sound insulator?? to me it looks like a thick version of Dryer Lint..
02-22-2007, 11:46 AM
#5
Team Owner
Thread Starter
02-22-2007, 10:03 PM
#9
Supporting Tuner
Good post 
Excellant posting.
02-23-2007, 01:59 PM
#13
Racer
Member Since: Nov 2004
Location: TX
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Good info. I would just like to add that from what I have seen in various printed materials, closed cell foam thickness made a tremendous difference. In the thicknesses we are talking about (1/4 - 1/2), the thickness made a a 1:1 ratio. I.e. if you double the thickness, you've also doubled the NRC (noise reduction coefficient).
Last edited by bomax; 02-23-2007 at 02:03 PM.
02-23-2007, 02:21 PM
#14
Le Mans Master
Sound Deadening 101
I'm posting this in order to help first timers, and maybe clear up some of the fog around sound deadening in general.
First, I want to make clear the differences between damping material and sound barrier material.
A quick definition:
Damping material reduces vibration on panels where it is applied. A sound barrier material acts to reduce outside noise.
What is damping?
The main idea behind damping a panel is to reduce its tendency to vibrate. A panel may vibrate and create noise, or it may result in distortion of sound. ie: If the panel with the speaker installed vibrates.
How does it work?
How damping works is simple - The more mass a panel has, the less likely it is to vibrate. Also, this lowers the resonant frequency. The more mass, the better.
Why do it?
This can greatly reduce the possibility of a panel buzzing. Particularly, door panels. Also, if a car's body panel is over your exhaust system, it could be resonating and creating interior noise. The less of your car flexing and vibrating when your sound system is playing, the better. Midbass can be increased with door applications.
Where to do it?
There is one place it should always be done: The door panel. Particularly behind the speaker, and on the surface of the panel. Aside from that: Anywhere that resonates. Tap your panels fairly hard. If they go pong! then deaden them until they go thud. If you want to save weight and money, don't bother deadening panels that already go thud. A good example in the C5 is most of the center tunnel, and the floor under the seats. I personally like to deaden the thin plastic interior panels as well. Doing this in my door panel reduced some midbass distortion I was getting.
What materials are available?
Butyl
Butyl is the best possible material for damping sheets. It's easy to cut, easy to work with. Generally does not require a heat gun, or any special considerations to install it. Butyl is also very likely to stay stuck where you put it.
Vinyl
While better than Asphalt, Vinyl still is somewhat harder to work with than butyl.
Asphalt
Asphalt is the 'old' way to do it. It's messier, can sometimes have an odor, and very possibly may lose adhesion. I would suggest steering clear of any asphalt sheets.
Liquid
Liquid has been gaining popularity, and I use it myself as a base layer. You have the advantage of being able to vary the thickness according to the shape of the panel, and you won't waste any material trying to wrap it around corners, or get it in tight spaces. The disadvantage to liquid is the time it takes to fully cure. Most take 24 hours at room temperature. And up to a week if you are like me and can't wait for summer.
What are the costs?
Cost can vary tremendously. My suggestion is to go with the thickest, cheapest, butyl mat available at the time. Right now, I believe that is Edead from Elemental Designs. Aside from that, you can get the material as cheap as $1 a square foot, $5 a square foot, and even more if you buy brands like Dynamat.
What doesn't it do?
Damping does not do much to filter out outside noise, or road noise. If you are applying damper to simply reduce road noise, you are wasting your money. And this brings us to the next half of the thread:
Killing Sound with a sound barrier
What is a sound barrier?
A type of material designed to reduce or reflect the sound that passes through it. A reduction of sound transmission.
Why do it?
You are looking to reduce road noise, or outside noise entering the car. Foam can also be used to reduce rattles, when stuffed in a rattle prone panel.
Where to do it?
The factory is pretty smart when it comes to this. Look for where they have added foam, and back it up with more foam. This foam is useful just about anywhere, but I'd start with the floorboards, over the wheel wells, and the back walls. Behind the engine (interior of course) and lastly, doors. In my install, I attached foam to the back of all plastic trim panels.
What materials are available?
Closed Cell Neoprene Foam
Available in 1/8 or 1/4 from various sound deadening suppliers. This material is very easy to work with, stretches easily, and tears when you want it to. It's somewhat compressible. The greatest advantage is that it should not mold, which is a concern with open cell foam, especially in the doors. FWIW, most factory cars use open cell foam.
Frost King
I believe Frost King is an open cell foam, and it is foil backed, and self adhesive. It is fairly easy to work with, though much more difficult than the neoprene sheets because of the foil backing. It is slightly less than 1/8" thick, and much less dense than closed cell neoprene. Frost King offers much less sound insulation than the other foam, but the foil layer does help against heat.
Composite Materials
There are a few materials available, at a much higher cost, which are gneerally very thick and are built as such: Foam - Vinyl - Foam. Or Foam - Lead - Foam. These tend to be the heaviest as well, but also the most effective.
What are the costs?
Frost King is about $1/ft^3. Neoprene is anywhere from $1-5 on up depending on thickness. RAAM Audio is the least expensive, and I would highly suggest buying 1/8 foam because of its flexibility, and then doubling up in areas where you can.
What doesn't it do?
From my basic testing (Using various materials as a sound barrier VS a speaker in a box playing pink noise, measured with my RTA) this thickness of foam does not make a massive difference. Most of the sound reduction is at frequencies over 1k. So for road noise below 1k, don't expect a big difference. This should help with tire noise fairly well though. Also, foam does not dampen a panel, please use damping under the foam in places you need to.
Hope this helps.
Weak Points in the C5
Now that I've got my Ensolite install complete, I'd like to point out a few places that will give you a nice improvement with foam. - Attach foam to the back of the B pillar trim panels. There is no factory sound insulation here. Not a lot of sound gets through here, but its right on top of your ear. One layer of 1/8 did perfectly for me.
Behind the seats, on the back wall. Put in as much as you can.
I'm posting this in order to help first timers, and maybe clear up some of the fog around sound deadening in general.
First, I want to make clear the differences between damping material and sound barrier material.
A quick definition:
Damping material reduces vibration on panels where it is applied. A sound barrier material acts to reduce outside noise.
What is damping?
The main idea behind damping a panel is to reduce its tendency to vibrate. A panel may vibrate and create noise, or it may result in distortion of sound. ie: If the panel with the speaker installed vibrates.
How does it work?
How damping works is simple - The more mass a panel has, the less likely it is to vibrate. Also, this lowers the resonant frequency. The more mass, the better.
Why do it?
This can greatly reduce the possibility of a panel buzzing. Particularly, door panels. Also, if a car's body panel is over your exhaust system, it could be resonating and creating interior noise. The less of your car flexing and vibrating when your sound system is playing, the better. Midbass can be increased with door applications.
Where to do it?
There is one place it should always be done: The door panel. Particularly behind the speaker, and on the surface of the panel. Aside from that: Anywhere that resonates. Tap your panels fairly hard. If they go pong! then deaden them until they go thud. If you want to save weight and money, don't bother deadening panels that already go thud. A good example in the C5 is most of the center tunnel, and the floor under the seats. I personally like to deaden the thin plastic interior panels as well. Doing this in my door panel reduced some midbass distortion I was getting.
What materials are available?
Butyl
Butyl is the best possible material for damping sheets. It's easy to cut, easy to work with. Generally does not require a heat gun, or any special considerations to install it. Butyl is also very likely to stay stuck where you put it.
Vinyl
While better than Asphalt, Vinyl still is somewhat harder to work with than butyl.
Asphalt
Asphalt is the 'old' way to do it. It's messier, can sometimes have an odor, and very possibly may lose adhesion. I would suggest steering clear of any asphalt sheets.
Liquid
Liquid has been gaining popularity, and I use it myself as a base layer. You have the advantage of being able to vary the thickness according to the shape of the panel, and you won't waste any material trying to wrap it around corners, or get it in tight spaces. The disadvantage to liquid is the time it takes to fully cure. Most take 24 hours at room temperature. And up to a week if you are like me and can't wait for summer.
What are the costs?
Cost can vary tremendously. My suggestion is to go with the thickest, cheapest, butyl mat available at the time. Right now, I believe that is Edead from Elemental Designs. Aside from that, you can get the material as cheap as $1 a square foot, $5 a square foot, and even more if you buy brands like Dynamat.
What doesn't it do?
Damping does not do much to filter out outside noise, or road noise. If you are applying damper to simply reduce road noise, you are wasting your money. And this brings us to the next half of the thread:
Killing Sound with a sound barrier
What is a sound barrier?
A type of material designed to reduce or reflect the sound that passes through it. A reduction of sound transmission.
Why do it?
You are looking to reduce road noise, or outside noise entering the car. Foam can also be used to reduce rattles, when stuffed in a rattle prone panel.
Where to do it?
The factory is pretty smart when it comes to this. Look for where they have added foam, and back it up with more foam. This foam is useful just about anywhere, but I'd start with the floorboards, over the wheel wells, and the back walls. Behind the engine (interior of course) and lastly, doors. In my install, I attached foam to the back of all plastic trim panels.
What materials are available?
Closed Cell Neoprene Foam
Available in 1/8 or 1/4 from various sound deadening suppliers. This material is very easy to work with, stretches easily, and tears when you want it to. It's somewhat compressible. The greatest advantage is that it should not mold, which is a concern with open cell foam, especially in the doors. FWIW, most factory cars use open cell foam.
Frost King
I believe Frost King is an open cell foam, and it is foil backed, and self adhesive. It is fairly easy to work with, though much more difficult than the neoprene sheets because of the foil backing. It is slightly less than 1/8" thick, and much less dense than closed cell neoprene. Frost King offers much less sound insulation than the other foam, but the foil layer does help against heat.
Composite Materials
There are a few materials available, at a much higher cost, which are gneerally very thick and are built as such: Foam - Vinyl - Foam. Or Foam - Lead - Foam. These tend to be the heaviest as well, but also the most effective.
What are the costs?
Frost King is about $1/ft^3. Neoprene is anywhere from $1-5 on up depending on thickness. RAAM Audio is the least expensive, and I would highly suggest buying 1/8 foam because of its flexibility, and then doubling up in areas where you can.
What doesn't it do?
From my basic testing (Using various materials as a sound barrier VS a speaker in a box playing pink noise, measured with my RTA) this thickness of foam does not make a massive difference. Most of the sound reduction is at frequencies over 1k. So for road noise below 1k, don't expect a big difference. This should help with tire noise fairly well though. Also, foam does not dampen a panel, please use damping under the foam in places you need to.
Hope this helps.
Weak Points in the C5
Now that I've got my Ensolite install complete, I'd like to point out a few places that will give you a nice improvement with foam. - Attach foam to the back of the B pillar trim panels. There is no factory sound insulation here. Not a lot of sound gets through here, but its right on top of your ear. One layer of 1/8 did perfectly for me.
Behind the seats, on the back wall. Put in as much as you can.
02-23-2007, 02:47 PM
#16
Racer
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Ensolite is half the price, but you get half the substance. But, if you consider the 20% forum discount we get at Elemental Designs for the v4, you see that the v4 is actually the cheaper solution if you plan to double up on the Ensolite.
Only advantage to Ensolite is that it's thinner and therefore easier to manipulate.
02-23-2007, 03:03 PM
#18
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02-23-2007, 03:23 PM
#20
Le Mans Master
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St. Jude Donor '06
yea it gets crazy here sometimes. Some days you can go all day with maybe 2 threads and other days there are like 30 threads going on and wondering what the hell is going on. Its easy to lose stuff here. I lost a couple of my threads that I wished I had saved. No clu what happened to them. 