Sound Deadening Material Independent Testing Data
People Lie, Numbers Dont.
Curious about who makes the best sound deadening material? Well, here is an extensive set of objective testing with the data completely broken-down to back and explain the results.
Change log: Updated February 17th, 2023
Topics - Click to Quick Jump
Introduction & General Overview
The testing and results below are all from an independent enthusiast, Chris Purdue, who is on his own journey to find out what the best products are in the sound deadening market. Chris is a high-end car audio enthusiast, just like a lot of you reading this page, and has been so for over a decade. He has years of experience, and has a vast understanding of audio and how it works.
This journey of his started years ago on the diymobileaudio.com forums and his previous testing can be found there. His ongoing testing and new data from utilizing his new testing equipment(video below) can be found on his Facebook group named “The Deadening” (link below).
The following data is all from this group – posted by Chris. If something about the article contradicts the data he has published for the world to use, please, let me know as it is nothing but a simple mistake. We are just here to try and help everyone interpret his data in a way that’s easy to digest.
Test Equipment Overview
So, before we dissect the data, we need to understand how these tests were done and what the data means. The first thing we need to go over is the test rig itself. The test rig is essentially two sealed enclosures with one shared wall separating them. The first enclosure is plain. Nothing about it is different from a standard sealed enclosure for a speaker. But the second enclosure has a removable metal panel that acts as the wall for the far end. Installed into the dividing wall is a speaker. The rear of the speaker fires into one enclosure. The front of the speaker fires into the second enclosure. A microphone placed just outside the metal panel measures acoustic data that the metal panel creates using the Room EQ Wizard measurement software. That information includes frequency response, impulse response, waterfall response, and more. This measurement is done before and after a Constrained Layer Damper is applied to the metal panel.
This gives us the before and after data and gives us an idea of how the CLD affects the panel. We can measure frequency response, as well as decay of the resonance. The two are typically correlated, but decay, while being more telling, is much harder to interpret into easy-to-understand numbers. So, for now, we are going to stick with frequency response. The frequency response will have a peak at the resonant frequency of said metal panel. In this case, that peak is around the 100hz area, which is also typical for a car door. We want to focus on how much reduction in amplitude this peak has to determine how effective the tested CLD is. The video below is of Chris explaining the test rig that he built and uses for testing as described above.
Best Car Sound Deadening Material Test Results
Car Sound Deadeners Independent Testing Data
ResoNix Mega CLD
19 dB reduction
ResoNix
17 dB reduction
3M EDP1029
10.25 dB reduction
Amazon Basics 90-mil
(Now only available in 70-mil thickness)
11.5 dB reduction
Soundskins Pro
9 dB reduction
Soundshield SSD 3-in-1
7 dB reduction
Boommat
8.25 dB reduction
Canopus
11 dB reduction
Dynamat Extreme
8 dB reduction
Harmony
13.75 dB reduction
Hushmat
10.25 dB reduction
Kilmat 80mil
7.25 dB reduction
Koxuyim
11 dB reduction
STP Aero
10.25 dB reduction
STP Gold
12.5 dB reduction
STP Silver
7.75 dB reduction
Sonic Barrier MX4
5.75 dB reduction
NVX CLD
11.5 dB reduction
Roadstage 3-in-1
8.5 dB reduction
Second Skin Damplifier Pro
11.5 dB reduction
Siless 80mil
8.25 dB reduction
Siless 50mil
4.75 dB reduction
Smartmat
9.75 dB reduction
Noico
9.5 dB reduction
Noico with Noico Roller
9.75 dB reduction
Noico with aggressive roller
7.5 dB reduction
The Measurements Of Sound Deadener Performance, & How To Interpret Them
Moving on to actually reading the results that are generated by Chris’s testing rig… The Decibel scale is measured logarithmic instead of linear. Every 3-decibel change, the energy is doubled or halved. If you have a speaker playing something at 85dB, twice the amount of energy is needed to hit 88dB. You will need twice the amount of power applied to the speaker or twice the number of speakers to achieve the 88dB. If you double the number of speakers and double the amount of power, that would be a 6dB addition. 50 decibels is NOT half as loud, or half the energy of 100 decibels. Pretty simple, right? Good. Let’s recap with bullet points real quick just in case.
- The decibel system is logarithmic, not linear.
- 3dB up is twice the energy. 3dB down is half the energy.
- 50dB is NOT half of 100dB. 25dB is not half of 50dB.
- 97dB is half the energy of 100dB. 103dB is 2x as much energy as 100dB.
- =10^(dB/10) is the formula for those who wish to know
ResoNix Mega CLD
.63 Sq Ft
ResoNix
1 Sq Ft
3M EDP1029
4.75 Sq Ft
Amazon Basics 90-mil
(Now only available in 70-mil thickness)
3.75 Sq Ft
Soundskins Pro
6.5 Sq Ft
Soundshield SSD 3-in-1
10 Sq. Ft.
Boommat
7.75 Sq. Ft.
Canopus
4 Sq. Ft.
Dynamat Extreme
8 Sq. Ft.
Harmony
2.25 Sq. Ft.
Hushmat
4.75 Sq. Ft.
Kilmat 80mil
9.5 Sq. Ft.
Koxuyim
4 Sq. Ft.
STP Aero
4.75 Sq. Ft.
STP Gold
2.85 Sq. Ft.
STP Silver
8.5 Sq. Ft.
Sonic Barrier MX4
13.5 Sq. Ft.
NVX CLD
3.6 Sq. Ft.
Roadstage 3-in-1
7.1 Sq. Ft.
Second Skin Damplifier Pro
3.6 Sq. Ft.
Siless 80mil
7.5 Sq. Ft.
Siless 50mil
17 Sq. Ft.
Smartmat
5.5 Sq. Ft.
Noico
5.65 Sq. Ft.
Noico with Noico Roller
5.25 Sq. Ft.
Noico with aggressive roller
9 Sq. Ft.
Square Footage Required To Match 1 Sq.Ft of ResoNix CLD Squares
(Lower Is Better)
Calculated via the amount of dB reduction on the given test panel. +3dB = 2x … 10^(dB/10). Can be viewed as a reverse performance multiplier. Example: a rating of 5 would mean the product is 5x worse than a product with a rating of 1.
ResoNix Mega CLD
$7.40
ResoNix
$8.50
3M EDP1029
$42.85
Amazon Basics 90-mil
(Now only available in 70-mil thickness)
$9.71
Soundskins Pro
$65.78
Soundshield SSD 3-in-1
$109.10
Boommat
$54.48
Canopus
$11.00
Dynamat Extreme
$41.76
Harmany
$11.57
Hushmat
$32.97
Kilmat 80mil
$16.91
Koxuyim
$9.32
STP Aero
$28.50
STP Gold
$11.76
STP Silver
$23.04
Sonic Barrier MX4
38.48
NVX CLD
$9.00
Roadstage 3-in-1
Price not available
Second Skin Damplifier Pro
$27.61
Siless 80mil
$13.95
Siless 50mil
$22.61
Smartmat
$10.62
Noico
$34.52
Noico with Noico Roller
$32.08
Noico with aggressive roller
$54.99
Rating Sound Deadener Performance
The rating system is simple. A CLD is supposed to do one thing and one thing only. Reduce resonance from a panel. So, while it’s the main focus, we will also be including a price-to-performance rating to give an idea of how products compare to what your dollar gets you. This price-to-performance rating is simple. The price per square foot of the product multiplied by its effectiveness in comparison to ResoNix.
Example: If ResoNix proves to be 2x better (3db difference) than another product, we take the price per square foot of the other product, and multiply it by 2. If this product costs $6.50 per square foot, and ResoNix costs $8.20 per square foot, we can now value the price to performance at $13 for this other product. While it may be cheaper, its not as good of an overall value as ResoNix.
Spoiler alert: ResoNix CLD Squares are currently the best independently tested product on the market. And frankly, it isn’t very close either. We expected this since our goal was to make the best performing product, hands down. Still, since it performed so well, we will use the ResoNix CLD Squares results as the reference.
Testing Of Ours
& Our Competitors
Everything You Need To Know About Automotive Sound Deadening & Sound Treatment Products.
Unfortunately, there is a lot of misinformation and marketing fluff out there when looking for
information on properly sound deadening your vehicle. I’m writing this to clear up any
misconceptions about installing any sound treatment to your car, as well as provide an easy-tofollow,
step-by-step guide that doesn’t misguide you for one reason or the other.
The Full Explanation Of Sound Deadener Performance - The Individual Measurements
Reference Measurements – No CLD Applied
Each product received a “before” measurement with no product applied to act as a reference. The only variance that exists is well below our resonance frequency. This resonance frequency is visualized as a sharp peak, and is the area we will be paying attention to, which is from about 100Hz to 150Hz for this specific test panel. Since all of the “before” measurements are very similar, we will just be using one randomly picked before measurement to keep things relatively simple.