Pwnm30rdi3
Member
Hey guys! I've seen a lot of posts recently with people going crazy covering their interiors with Dynamat.
I wanted to inform you that you are doing it wrong. Dynamat or (CLD) Constrained-Layer Deadener wasn't designed to block or absorb sound. It was designed to absorb vibrations. While CLD is important, you should consider sticking to the 25% rule.
Please give this a quick read:
To sum everything up:
25% coverage is 6db louder and 50% coverage is 3db louder than 100% coverage. To put this into perspective, 30db is a whisper.
Then there is the Absolute Threshold of Hearing. The Absolute Threshold of Hearing theory states that on average, the human ear will not notice a 3-4db swing in volume. So say you listen to a beep with no other background noises present. If the beep plays at 40db and 42db, you wont be able to notice a difference. Yet, if the beep plays at 43+db you have a higher chance of noticing the difference in volume.
Then you have to debate with yourself how much that 6db — that you probably wont notice — is worth. So say 100% coverage of a crew cab floor, doors, back wall, and a-pillars = ~85 Sq/Ft.
Well 85 Sq/Ft of nice quality CLD runs you about $400 before shipping. UPS ground says shipping will cost $75.00 on 85 Sq/Ft. So now you are looking at a total of $475.00 for 100% coverage of CLD. (Keep in mind that number is excluding all coverage of CLD on the roof.)
Now at 25% coverage of CLD you are looking at about 22 Sq/Ft. Well 22 Sq/Ft will run you around $125 and shipping is only about $25. That's a total of only $150 for 25% coverage.
Is the $325.00 difference worth the 6db difference? For some yes. For me, no. In a blind test I wouldn't be able to tell you the difference between 25% vs 100% coverage.
I would be much happier spending my $325 on other materials that will actually absorb sound.
When I applied my CLD, I applied more in some areas. For example, on my floor I followed the 25% rule pretty strictly. But for the wall behind the rear seat I went with 50% coverage because of how thin the sheet metal is there. (Use good judgement) Dampener can also be used for many other good things, such as sealing off those gigantic holes behind your door panels. When you seal those holes up, you'd be amazed by how great your door speakers sound! Your door acts like a hermetically sealed subwoofer box.
So with that extra money you saved by only using 25% of CLD, spend it on other materials that will actually block and absorb sound.
Another great material that blocks sound (not absorption) is MLV or Mass Loaded Vinyl. Keep in mind this stuff usually weighs around 1.5-2lbs per sq/ft and can be hard to glue.
You also want to use some good material for sound absorption. I like using fiberglass insulation from Lowes. Pull the paper backing off and use spray adhesive to get it to stick. Under dash, inside door panels, and many more places! This stuff is amazing.
I also like using the carpet padding that you can buy at Lowes.
Combine a good amount of all of these materials and you will be in great shape.
Remember that your glass will always be the weakest point. You can only do so much with sound deadener before your glass and weatherstripping limit you.
I really hoped this helped. I enjoy sharing my knowledge and wanted to give back to everyone here for their help and support.
I wanted to inform you that you are doing it wrong. Dynamat or (CLD) Constrained-Layer Deadener wasn't designed to block or absorb sound. It was designed to absorb vibrations. While CLD is important, you should consider sticking to the 25% rule.
Please give this a quick read:
If you want to read even more about CLD (Constrained-Layer Dampening), read this PDF: http://www.earsc.com/pdfs/engineering/understandingdamping.pdf
To sum everything up:
25% coverage is 6db louder and 50% coverage is 3db louder than 100% coverage. To put this into perspective, 30db is a whisper.
Then there is the Absolute Threshold of Hearing. The Absolute Threshold of Hearing theory states that on average, the human ear will not notice a 3-4db swing in volume. So say you listen to a beep with no other background noises present. If the beep plays at 40db and 42db, you wont be able to notice a difference. Yet, if the beep plays at 43+db you have a higher chance of noticing the difference in volume.
Then you have to debate with yourself how much that 6db — that you probably wont notice — is worth. So say 100% coverage of a crew cab floor, doors, back wall, and a-pillars = ~85 Sq/Ft.
Well 85 Sq/Ft of nice quality CLD runs you about $400 before shipping. UPS ground says shipping will cost $75.00 on 85 Sq/Ft. So now you are looking at a total of $475.00 for 100% coverage of CLD. (Keep in mind that number is excluding all coverage of CLD on the roof.)
Now at 25% coverage of CLD you are looking at about 22 Sq/Ft. Well 22 Sq/Ft will run you around $125 and shipping is only about $25. That's a total of only $150 for 25% coverage.
Is the $325.00 difference worth the 6db difference? For some yes. For me, no. In a blind test I wouldn't be able to tell you the difference between 25% vs 100% coverage.
I would be much happier spending my $325 on other materials that will actually absorb sound.
When I applied my CLD, I applied more in some areas. For example, on my floor I followed the 25% rule pretty strictly. But for the wall behind the rear seat I went with 50% coverage because of how thin the sheet metal is there. (Use good judgement) Dampener can also be used for many other good things, such as sealing off those gigantic holes behind your door panels. When you seal those holes up, you'd be amazed by how great your door speakers sound! Your door acts like a hermetically sealed subwoofer box.
So with that extra money you saved by only using 25% of CLD, spend it on other materials that will actually block and absorb sound.
Another great material that blocks sound (not absorption) is MLV or Mass Loaded Vinyl. Keep in mind this stuff usually weighs around 1.5-2lbs per sq/ft and can be hard to glue.
You also want to use some good material for sound absorption. I like using fiberglass insulation from Lowes. Pull the paper backing off and use spray adhesive to get it to stick. Under dash, inside door panels, and many more places! This stuff is amazing.
I also like using the carpet padding that you can buy at Lowes.
Combine a good amount of all of these materials and you will be in great shape.
Remember that your glass will always be the weakest point. You can only do so much with sound deadener before your glass and weatherstripping limit you.
I really hoped this helped. I enjoy sharing my knowledge and wanted to give back to everyone here for their help and support.
