Independent Testing Data

Cold, Hard, Facts.

Curious about who makes the best sound deadener? Well, here is a complete breakdown with the completely broken-down data to back and explain it.

Remember, People Lie

Numbers Don't

Last Updated April 16th 2023: NEW ROUND OF TESTING COMPLETED

Note: This testing is not done by, nor paid for by ResoNix, or any of the brands or products mentioned below.


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 forums. His previous testing can be found there. On his new test rig (video of it posted below), his new ongoing testing and its results 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.

The Deadening Facebook Group

The original article has since been retired (but can be found here) since Chris has done a new and much larger round of testing featuring all of the old products, but also a whole bunch of products that were never tested. This updated article is going to be very similar to the last but is updated with results from the new round of testing. 

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 in the frequency response 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. Video of Chris explaining the test rig below.

Moving on… 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

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.



Results - Quick Summary

Resonance Reduction - 25% Coverage On Test Panel Seen Above (Higher Is Better)

Resonance Reduction is the basis for performance. The more resonance removed, the better.

ResoNix CLD Squares: 17dB reduction
Soundshield SSD1 3-in-1: 7dB reduction
SoundSkins Pro: 9dB reduction
Amazon Basics: 11.5dB reduction
Stinger Roadkill Extreme: 12.25dB reduction
3m EDP1029: 10.25dB reduction
Boommat: 8.25dB reduction
Canopus: 11dB reduction
Dynamat Extreme: 8dB reduction
Harmany: 13.75dB reduction
Hushmat: 10.25dB reduction
Kilmat 80mil: 7.25dB reduction
Koxuyim: 11dB reduction
STP Silver: 7.75dB reduction
STP Gold: 12.5 reduction
STP Aero: 10.25dB reduction
Sonic Barrier MX4: 5.75dB reduction
NVX CLD: 11.5dB reduction
Roadstage3-in-1: 8.5dB reduction
Second Skin Damplifier Pro: 11.5dB reduction
Siless 80mil: 8.25dB reduction
Siless 50mil: 4.75dB reduction
Smartmat: 9.75dB reduction
Noico: 9.5dB reduction
Noico with Noico Roller: 9.75dB reduction
Noico with aggressive roller: 7.5dB reduction

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)

ResoNix CLD Squares: 1
Soundshield SSD1 3-in-1: 10
SoundSkins Pro: 6.5
Amazon Basics: 3.75
Stinger Roadkill Extreme: 3
3m EDP1029: 4.75
Boommat: 7.75
Canopus: 4
Dynamat Extreme: 8
Harmany: 2.25
Hushmat: 4.75
Kilmat 80mil: 9.5
Koxuyim: 4
STP Silver: 8.5
STP Gold: 2.85
STP Aero: 4.75
Sonic Barrier MX4: 13.5
NVX CLD: 3.6
Roadstage3-in-1: 7.1
Second Skin Damplifier Pro: 3.6
Siless 80mil: 7.5
Siless 50mil: 17
Smartmat: 5.5
Noico: 5.65
Noico with Noico Roller: 5.25
Noico with aggressive roller: 9

Price To Performance Equivalent Vs. ResoNix CLD Squares (Lower Is Better)

Price Per Sq Foot x Sq. Footage Required To Match Performance Of 1 Sq Foot Of ResoNix CLD Squares

ResoNix CLD Squares: $8.5
Soundshield SSD1 3-in-1: $109.1
SoundSkins Pro: $65.78
Amazon Basics: $9.7125
Stinger Roadkill Extreme: $18.24
3m EDP1029: $42.845
Boommat: $54.4825
Canopus: $11
Dynamat Extreme: $41.76
Harmany: $11.565
Hushmat: $32.965
Kilmat 80mil: $16.91
Koxuyim: $9.32
STP Silver: $23.035
STP Gold: $11.756
STP Aero: $28.5
Sonic Barrier MX4: $38.475
Roadstage3-in-1: Price Not Available
Second Skin Damplifier Pro: $27.612
Siless 80mil: $13.95
Siless 50mil: $22.61
Smartmat: $10.615
Noico: $34.5215
Noico with Noico Roller: $32.0775
Noico with aggressive roller: $54.99

CLD Testing Results Resonance Reduction Chart
Resonance Reduction In Decibels (Higher Is Better)
How Much product Required Sq Footage
How Much Square Footage Required To Match 1 Square Foot Of ResoNix CLD Squares (Lower Is Better)
Price To Performance Ratio Relative to The Price & Performance Of ResoNix CLD Squares (Lower Is Better)
Value Per Square Foot of popular industry products best sound deadener
Price To Performance Ratio Of Popular Options In The US Relative To ResoNix CLD Squares (Lower Is Better)

The Full Explaination - The Individual Measurements

Reference Measurements - No CLD Applied

Sound Deadener Test All Bare Panel Measurements
The "Before" Measurements For All Products Tested

ResoNix CLD Squares

Since all of the “before” measurements are very similar, we will use one to keep it simple.

First up, ResoNix CLD Squares. As you can see in the multiple before/after measurement, panel resonance has a 17dB reduction with the application of ResoNix CLD Squares. As mentioned earlier, this is going to be our reference. So from here on out, if another product has a 3db difference from ResoNix, ResoNix would be 2x as effective. If it had a 6db difference, it would be 4x as effective. If there is a 9db difference, that would be 8x as effective. 12db difference, 16x more effective, and so on. Remember, the db scale is logarithmic.

First picture from the old testing, second picture from the new testing. 

ResoNix CLD Squares Test Results
ResoNix CLD Squares - First Round
ResoNix CLD Squares Test 2 Results
ResoNix CLD Squares - Second Round

Dynamat Extreme

Next up is the Kleenex of sound deadener, Dynamat Extreme. This is the most popular product for aftermarket automotive use worldwide, and they have been around for decades. Looking at the measurements from the original test, Dynamat Extreme drops the peak in the resonant frequency from 106.5dB to 98.5dB. An 8dB reduction in the resonance of the test panel. In the new test, it also drops it exactly 9db. ResoNix being at a 17dB reduction in the test panel, is 8x as effective as Dynamat Extreme per given amount (9dB more equates to 8x the amount of energy). So, for every square foot of ResoNix CLD Squares, you would need 8 square feet of Dynamat Extreme to, in theory, yield the same result. At the time of writing this, we were able to find Dynamat Extreme online for as low a $5.22 per square foot. This generates a price-to-performance of $41.76 vs. ResoNix $8.50. In theory, to get the same end result as ResoNix, you would be paying 5x the overall price and doing 8x the work overall. In reality, it wouldnt be possible to match the performance of ResoNix CLD Squares with Dynamat Extreme since the performance ceiling is so much lower on Dynamat Extreme, unless doing very minimal coverage with ResoNix. This is not a good value.

First picture is the old test results. Second picture is the most recent testing results.

ResoNix CLD Squares Vs Dynamat Extreme CLD Sound Deadener Test Results
ResoNix CLD Squares Vs Dynamat Extreme CLD Sound Deadener Test Results - First Round
ResoNix Sound Solutions CLD Squares vs Dynamat Extreme Sound Deadener
ResoNix CLD Squares Vs Dynamat Extreme CLD Sound Deadener Test Results - Second Round


Up next is 3M’s EDM. This is a new product that is different from traditional Butyl/Aluminum CLD’s. Its purpose is to be extremely light yet practical. The downside is, you pay a premium for the lightweight for average performance. We are leaving the ResoNix CLD measurement visible to use as a visual gauge, but remember, another product being visually halfway in between the “before” peak and the ResoNix measurement does not mean the other product is half as good. Remember, every 3db difference is 2x the energy. In the original testing, 3M measures at 96dB (we are rounding to the nearest half dB in favor of the product to make this easier) vs. the Before Measurement of 106.5dB. 10.5dB is the amount of resonance reduction we have. In the new round of testing, it reduced the peak by 10.25db, so pretty much the same result. 6.75db less than ResoNix, making ResoNix about 4.75x as effective per square foot. We were able to find this product for as low as $9.02 per square foot. We can calculate that, in theory, you would need to spend $42.85 to get enough of the 3M product to achieve the same result as the $8.50, 1 Square foot of ResoNix CLD Squares. In the original testing, this is the worst value product in the entire test regarding resonance reduction. In the new testing, there are some that are grossly more overpriced. 

First picture is the original round of testing, second picture is the new round of testing.

3M EPM vs ResoNix CLD Squares Sound Deadener Test Results
ResoNix CLD Squares vs 3M EPM Sound Deadener Test Results - First Round
ResoNix Sound Solutions CLD Squares vs 3M EDM1029 Sound Deadener
ResoNix CLD Squares vs 3M EPM Sound Deadener Test Results - Second Round

Kilmat 80mil

Next up, we have a recently popular product, Kilmat 80mil. This has become very popular among car audio hobbyist and camper van groups and pages as a good budget option. Well, let’s look at the data to see if it truly is a good budget option. Looking at the graph from the original testing, Kilmat 80mil reduces the resonance peak from 106.5dB to 98.5dB. The same reduction as Dynamat Extreme, but Dynamat Extreme also lowers the resonant frequency of the panel vs. Kilmat 80mil. From this, we can assume that Dynamat Extreme is heavier than Kilmat. When looking at two products that reduce the resonance amount equally, we would then determine the better performing product by picking the one which moves the resonance peak more outside of our desired passband the most. In this case, Dynamat Extreme outperforms Kilmat.

 In the NEW round of testing, the performance of Kilmat dropped slightly, and this time had a resonance peak reduction of only 7.25db. Based on my experience with these products, I would think its safe to say that this performance decrease can be from two different things. The manufacture either skimping on the quality of the product in more recent batches, or the butyl quality been very poor and degrading very quickly. Now comparing to ResoNix CLD Squares. Since this is a 9.75db difference, it can be calculated that ResoNix is 9.5x as effective per given amount vs. Kilmat 80mil. Kilmat 80mil comes out to $1.78 per square foot, so doing the calculation, we get a price to performance value of $16.91 to, in theory, achieve the same result as a single square foot of ResoNix CLD. 9.5x as much would need to be applied in order to match the performance of ResoNix CLD Squares. More work to apply, more cost overall to achieve a given amount of performance. This, while seemingly low cost, is not a good value. Remember, subjective reviews on the internet are typically not a great source of accurate information. People lie, numbers don’t.

First picture from the original testing. Second picture from the most recent testing.

ResoNix CLD Squares vs Kilmat 80mil CLD Sound Deadener Testing Results
ResoNix CLD Squares vs Kilmat 80mil CLD Sound Deadener Testing Results - First Round
ResoNix Sound Solutions CLD Squares vs Kilmat 80mil Sound Deadener
ResoNix CLD Squares vs Kilmat 80mil CLD Sound Deadener Testing Results - Second Round


Moving on, we have the slightly more expensive big brother of Kilmat, Noico 80mil. These products are both made by the same manufacture with similar formulas. The Kilmat is just a watered-down version of Noico, so let’s see what the Noico 80mil can offer. In both the original and most recent testing, the graph shows a 9.5dB reduction in the resonance peak. Definitely better than the Kilmat. Also, it lowers the resonance frequency lower than Kilmat. Looking at this, Noico is definitely a much better performer than its sister product Kilmat. Now comparing it to ResoNix. ResoNix lowers the resonance peak another 7.5dB lower than Noico. This equates to ResoNix being 5.65x more effective at reducing resonance in a given panel. Noico can be found for as low as $6.11 per square foot (prices drastically went up since the war in Ukraine since Noico, Kilmat, and other STP produced products are made in Russia). Price to performance vs. ResoNix CLD Squares, you would spend $34.52 to get enough Noico to, in theory, be as effective as ResoNix. 5.65x the amount would need to be applied. This is also not as good of a value, especially when you consider the extra work required to apply all of that additional product.

First picture is of the original testing, the second picture is from the more recent testing.

ResoNix CLD Squares vs Noico CLD Sound Deadener Test Results
ResoNix CLD Squares vs Noico CLD Sound Deadener Test Results - First Round
ResoNix CLD Squares vs Noico CLD Sound Deadener Test Results - Second Round


Next up is NVX 90mil. In both the original and more recent testing, it reduced the resonance peak by 11.5db. Not bad. Let’s see how it compares in value to ResoNix CLD Squares. We were able to find NVX 90mil for as low as $2.50 per square foot when buying a bulk pack. Remember, ResoNix reduces the test panel’s resonance by 17db. NVX 90mil reduced the panel’s resonance by 11.5db. Based on this, we can calculate that ResoNix is 3.6x as effective as NVX. This means you would need to, in theory, apply 3.6x as much NVX 90mil to the test panel to get the same reduction as a given piece of ResoNix CLD Squares. Taking that 3.6x multiplier to their $2.50 per square foot price, we can calculate its price to performance would be $9, vs. ResoNix $8.50. We finally have something close, but when using this product, you would then have to go through the additional work of applying 3.6x as much product vs. ResoNix CLD Squares to get the same performance. Close, but no cigar.

One more thing to note, according to international shipping records, this is made by the same manufacture that produces the KnuKnocepts deadener that is notorious for melting.

First picture is from the original testing, second picture of the more recent testing. 

ResoNix CLD Squares vs NVX CLD Sound Deadener Test Results
ResoNix CLD Squares vs NVX CLD Sound Deadener Test Results - First Round
ResoNix CLD Squares vs NVX CLD Sound Deadener Test Results - Second Round

Roadstage Audio

Next, we have Roadstage Audio, which is a “3-in-1” product. Butyl, foil, and foam all in one package. Lets see how effective it is at reducing panel resonance. As you can see on the graphs, Roadstage reduced the resonance peak by 8.5db in the original and more recent testing. ResoNix 17dB reduction allows us to calculate that ResoNix is 7.1x as effective per given amount compared to Roadstage Audio. I cannot find a website for Roadstage, let alone pricing, so we have no way to calculate the price to performance ratio. That said, I have a hard time believing that it’s cheap enough (especially considering it’s a 3-in-1 product) to be anywhere in the ballpark of the value of ResoNix CLD Squares.

Another thing to note, according to international shipping records, this is the first “3-in-1” product that I have seen that isnt manufactured by the one that makes almost every other 3-in-1 product, which are notorious for poor performance in both resonance control, as well as melting. I’m confident Roadstage has better heat resistance, and better resonance damping performance.

First picture is from the original testing, second picture from the more recent testing.

ResoNix CLD Squares vs Roadstage Audio CLD Sound Deadener Test Results
ResoNix CLD Squares vs Roadstage Audio CLD Sound Deadener Test Results - First Round
ResoNix Sound Solutions CLD Squares vs Roadstage Sound Deadener
ResoNix CLD Squares vs Roadstage Audio CLD Sound Deadener Test Results - Second Round

Sonic Barrier

Next up, we have Sonic Barrier MX-4. Another 3-in-1 product similar to Roadstage. Frankly, there are a LOT of products like this nowadays. Almost all of them are made by one manufacturer overseas with a different logo applied for each company. Roadstage says theirs is from another factory, and international shipping records confirm that. But Sonic Barrier is one of the ones in the “same as the rest” group. The only difference you can really get is butyl and foam thickness. Sonic Barrier is the only one in the original test that I know for a fact is from specific this manufacturer, but there are a couple of others from them in the more recent testing and their results can be seen below (Soundshield and Soundskins). So, getting into the test results. Sonic Barrier MX-4 reduced the panel resonance from 106.5dB to 99.5dB, a 7dB reduction in the original testing. In the more recent testing, it only reduced the resonance peak by 5.75db. Personally, I would say this difference has to due with the butyl formula being of very poor quality and having very poor longevity, since this is the same batch used from before. 

With the old testing, considering ResoNix had a 17dB reduction, we can calculate that ResoNix is exactly 10x as effective per given area covered than Sonic Barrier MX-4.  We were able to find Sonic Barrier MX-4 for $2.85 per square foot. The price to performance value comes out to $28.50 vs. ResoNix at $8.50 per square foot. While the initial cost is attractive, this is not a good value. 

With the more recent testing, ResoNix proves to be 13.5x as effective as Sonic Barrier, and Sonic Barrier would have an equal performance value of $38.48 per square foot vs ResoNix $8.50 per square foot. This product, while no longer produced, was a terrible value and overall one of the worst products tested.

Something to take note of regarding the info above, while they don’t have the same thickness specs, the manufacturer of Sonic Barrier also makes pretty much all of the popular “3-in-1” products, such as Soundshield, Sound Skins, SQL Sound Mat, Sky High 3-in-1, GP STFU, Siless Hybrid, Focal, Blackhole, Morel Accudamp, DC Audio, Sundown, B2, and more. These all use the same butyl formula that is known for poor resonance control, as well as melting (as seen in the Reference Information & Guide page). Buyer beware.

First photo is of the original testing, second photo is of the more recent testing. 

ResoNix CLD Squares vs Sonic Barrier CLD Sound Deadener Test Results
ResoNix CLD Squares vs Sonic Barrier CLD Sound Deadener Test Results

Second Skin Damplifier Pro

Up next is Second Skin Damplifier Pro. This is regarded as one of the better CLD’s on the market, and they have a very strong marketing push claiming so. Since we know marketing means squat when it actually comes time to using a product, let’s see what the data says. According to the original testing graph, we have a resonance peak reduced from 106.5dB to 95.5dB, an 11dB reduction. In the new testing, we have the same 11db resonance reduction results. This is among some of the better products, but definitely not the best. Let’s compare to ResoNix to see what value you get. ResoNix CLD Squares reduce 17dB of the test panel’s resonance, a 6dB difference vs. the Second Skin Damplifier Pro. This 6dB difference equates to ResoNix being 4x as effective per given amount than the Second Skin Damplifier Pro. You can get Second Skin Damplifier Pro for $7.67 per square foot if you order their 36sq foot foot bulk pack, similar to our 40 Square Foot pack of ResoNix CLD Squares. Second Skin Damplifier Pro price to performance ratio comes out to $30.68 vs. ResoNix $8.50. And again, you would still need to go through the work of applying, in theory, 4x the amount to get the same result. While I am happy that they are one of the only other American made products out there, this is not a good value.

First photo is from the original testing, second photo from the more recent testing. 

ResoNix CLD Squares vs Second Skin Damplifier Pro CLD Sound Deadener Test Results
ResoNix CLD Squares vs Second Skin Damplifier Pro CLD Sound Deadener Test Results

This concludes the products that were tested in November 2021. The rest of the products tested below were all done in the more recent testing done in April of 2023.


Note: the SoundShield that was tested was their standard product, not the slim version, or vinyl based product.

I would be lying to say I wasn’t anticipating seeing this product tested. SoundShield has become extremely in the car audio industry in recent years after the owner parted ways from distributing SoundSkins in the US. Frankly, the only thing that appeared to be new were the logos. SoundShield is another one of the “3-in-1” products made overseas by a less than reputable manufacturer that has a history of producing some of the worst performing sound deadeners available today, both from a resonance control standpoint, as well as their resistance to melting, which there is a long history of complaints for. But how does it actually perform on paper? Let’s find out. In the more recent testing results seen in the photo below, SoundShield reduced the resonance peak by only 7db. Considering they have the same results and same manufacturer, I think its safe to say the only difference between this and Sonic Barrier is the logo. 

Spoiler Alert: Price to performance wise, SoundShield comes in as the worst of any product tested so far by a long shot. Considering it is $10.91 per square foot, and ResoNix is 10x as effective, it can be calculated to have a price to performance of $109 to ResoNix $8.50. Yikes. Considering the resonance control performance, history of melting from the manufacturer, and price to performance ratio… I have no words. 


Another “3-in-1” product from “that” manufacturer and is another popular option among car audio shops. Due to the history of SoundSkins/Soundshield in the US, I always suspected they were identical products. While I don’t expect much from the aforementioned manufacturer or the brands that order from them, they can still request different thicknesses in butyl, aluminum, and foam, which can change performance. It’s hard to say because these companies don’t even seem to care enough to put thickness specs in their literature. Let’s see if my suspicions were correct.

Turns out, I was wrong. It looks like SoundSkins is a slightly better performer than SoundShield. There is most likely a difference in butyl thickness. This may also explain why there are more reports of SoundSkins melting than there are of SoundShield (less butyl, the less of a chance it has to run/drip). SoundSkins reduced the resonance peak by 9db, which puts ResoNix as 8x more effective. Doing the formula for price to performance, this puts SoundSkins, which comes in at $10.12 per square foot, as the second worst price-to-performance product on the list coming in at $65.78.

Amazon Basics

Next up, the king of consumerism.. Amazon Basics. A year or so ago as of writing this, Amazon decided to get their skin in the sound deadening game. Many are weary, as we know it is most likely that they didn’t have a smidge of care and just found the cheapest thing they can put their name on and distribute worldwide, as with all things they put under the Amazon Basics name. So let’s see what the data says.

Turns out, its actually not half bad.  Resonance reduction comes in at 11.5db, which puts it in the middle of the pack, better than most. In relation to ResoNix CLD Squares 17db reduction, ResoNix comes in at 3.75x better than Amazon, and puts Amazon Basics CLD at a price to performance ratio of  $9.71 vs ResoNix $8.50. Close, but no cigar. I am eager to see how it does in Chris’s heat testing.

Stinger Roadkill Expert

Stinger Roadkill Expert has been a popular option for many car audio shops over the years as well. Using it in the past, I expected it would end up a little bit above average. Testing shows that to be true, coming in with a resonance reduction of 12.25db vs Resonix 17db reduction, putting ResoNix CLD Squares at 3x better than Stinger Roadkill Expert. Pricing comes in at $6.08 per square foot, and gives it a price to performance ratio of $18.24. Being another overseas made product, I am curious to see its heat resistance testing results. 


Next up is Boommat. Honestly, I’m not really sure what to say about them as I havent paid much attention to them at all and have never seen their products in person. So, lets dive into the test results. For resonance reduction, Boommat reduced the resonance peak of the test panel by 8.25db, so this is a pretty low performer. ResoNix being at 17db resonance reduction puts it as 7.75x better than Boommat. This gives Boommat, which comes in at $7.03 per square foot, a price to performance ratio of $54.48. So not only is it a low performer, it is also a poor value. 


Canopus is apparently a new sound deadener brand on the market that is made in asia. How long they have been around for exactly, I can’t say as this test was the first time I had heard of them. Looking into them, I really can’t find much info. So anyways, on to its testing results. Canopus reduced the resonance peak of the test panel by 11db, so not terrible, but definitely not great. ResoNix comes in at 4x as effective with its 17db resonance reduction. The pricing I managed to find for Canopus puts it at $2.75 per square foot, which gives it a price to performance ratio of $11, vs ResoNix $8.50. Once again, I am curious to see its heat testing results as many of these asia produced brands have so few real world, long term reviews since they are so new. 


Another random product that I haven’t heard of that Chris’s managed to get his hands on to test. Looking into it, it looked oddly familiar. I did some digging and found out that this is also from the same manufacturer of KnuKonceptz sound deadener, which has a bad history of melting product, so buyer beware. Anyways, on to the testing results. Also like Knu Konceptz, while having very poor resistance to heat and melting, it has good resonance control. It is actually the second place product when it comes to resonance control. It reduced the resonance peak of the test panel by 13.75db, which puts ResoNix CLD Squares as 2.25x better in resonance control performance. Coming in at $5.14 per square foot, it puts its price to performance ratio at $11.57 vs ResoNix CLD Squares $8.50. It is one of the better values of the bunch when it comes to resonance control, but like Knu Konceptz, I am very skeptical for how it will hold up in an automotive environment. Once again, I cannot wait to see Chris’s results from heat testing.


Hushmat is another American-made CLD that is known in the car audio industry. This is something I have had my hands on in the past, and honestly, I really expected this to do pretty poorly. Well, According to the results, I was actually wrong (goes to show that anyones subjective interpretation can be off from the truth). It did average, which was honestly much better than I expected. It came in at 10.25db of panel resonance reduction. This puts ResoNix CLD Squares at 4.75x better. Hushmat comes in at $6.94 per square foot, which gives it a price to performance ratio of $32.97 vs ResoNix $8.50. While it isnt a great performer or a great value, I am still wondering how it did as well as it did considering my subjective experiences with it. 


Another product coming from Asia that I haven’t personally heard of, so let’s dive into the data. Koxuyim reduced the test panels resonance peak by 11db, which is about average, but puts ResoNix CLD Squares as 4x better. Koxuyim comes in at $2.33 per square foot, which gives it a price to performance ratio of $9.32 vs ResoNix $8.50. Another close contender for value, but once again we have no idea how well it holds up to heat and will have to wait until Chris heat tests it. 

STP Silver

STP, short for Standartplast, is a Russian manufacturer that is the company that makes many of the other Amazon-sold products that are popular, such as Noico, Kilmat, etc. Since the start of the Ukranian war, STP products are no longer imported into the US, but we figured the data can be useful. I also have a lot of experience using this product since a shop I worked for years ago used it, and I always had a hunch that STP silver was the very same product as Kilmat or Noico, especially considering Standartplast makes both. Let’s see what the data says. According to Chris’s testing, STP Silver reduced the test panel resonance peak by 7.75db, close enough to Kilmat to say that they are probably the same product. With a reduction of 7.75db, it puts ResoNix as 8.5x better. According to the price sheet, it came in at $2.71 per square foot, which gives it a price to performance of  $23.04 compared to ResoNix CLD Squares $8.50. Another thing to note, considering I have a lot of experience with this product from years of installing it while working at another shop, it does not hold up well to heat over time. It tuned into a vaseline-like consistency after a couple years of being in my doors. 

STP Gold

STP Gold is the same product, just a thicker version, of STP Silver. STP Gold reduced the test panel resonance by 12.5db, making ResoNix CLD Squares 2.85x more effective. STP Gold had a price of $4.13 per square foot, which gives it a price to performance of $11.76 vs ResoNix CLD Squares $8.50. Considering it is the same butyl formula as STP Silver and my experiences with that, I would not recommend it unless you live in a colder climate (I am in New York and still had issues).

STP Aero

STP Aero is marketed as the even bigger and badder brother of STP Gold. Well, data shows otherwise. STP Aero reduced the test panels resonance peak by 10.25db, so its “little” brother, STP Gold, is actually a better performer. Relative to ResoNix, ResoNix proves to be 4.75x more effective. STP Aero had a price per square foot of $6.00 per square foot, and doing the price to performance calculation, turns out to be $28.50 relative to ResoNix CLD Squares $8.50. Average performer, poor value. 

Smartmat 90mil

Another random constrained layer damper from Amazon it seems, Smartmat 90mil seems really fancy looking and looks like a good budget to those who arent as educated on the subject. It turns out its resonance control performance is average at best. Smartmat reduced the test panels resonance peak by 9.75db, which makes the 17db reduction by ResoNix CLD Squares 5.5x as effective. Smartmat 90mil comes in at $1.93 per square foot, which gives it a price to performance equivalence of $10.62 vs. ResoNix CLD Squares $8.50. This is another product that I am very curious to see how it does in long-term heat testing. 

Siless 80mil

The last of the bunch that Chris tested was the Siless 80mil and 50mil. These are also becoming very popular options in the car audio, van build-out, and general automotive world, like many of these other products, due to their cheap price. Well, yes it may be cheap, but does it actually get you your moneys worth? Let’s see. The Siless 80mil reduced the resonance peak of the test panel by 8.25db, which is definitely on the low side of the bunch. This makes the 17db reduction by ResoNix CLD Squares 7.5x more effective. Siless 80mil has a price of $1.86 per square foot. Doing the math to give us is price to performance vs ResoNix, it comes out at $13.95 per square foot. So, while it may be cheap, it is definitely not a good value, and is definitely a very poor performer. Considering this is 80mil thick butyl it makes me wonder how much this product is loaded with fillers, and if the aluminum is even aluminum (some lower end products have used mylar in the past). Who knows, but it is a poor performer.  

Siless 50mil

And last, and spoiler alert, also the least.. Siless 50mil. Siless, as mentioned has become popular for its cheap price, and the 50mil version is even cheaper than its original counterpart. Getting into it, Siless 50mil reduced the test panels resonance peak by a mere 4.75db. This is by far the lowest performing product tested to date outside of fatmat and peel-and-seal, which are aslphalt products and Chris hasnt bothered to test on his new rig. With the 4.75 resonance reduction, it makes ResoNix CLD Squares are 17x more effective per given amount of coverage. How does this relate to its price to performance? Well, considering Siless 50mil is $1.33 per square foot, that makes its price to performance equal to $22.61 per square foot in relation to ResoNix CLD Squares $8.50 per square foot. I truly didn’t know a butyl based product could perform this poorly. It again, makes me wonder what it is truly comprised of.

Below, you can see all the results stacked onto the graph with the reference "before application" measurement. ResoNix CLD Squares is the green trace highlighted in yellow.

So here are some bar graphs to represent resonance control (how much reduction in resonance each product had), and a graph to represent the amount of square footage needed of a given product to match the performance of 1 square foot of ResoNix CLD Squares.

This last picture shows the visual representation of some of the price-to-performance values that we calculated of some of the more popular products in the industry. Since some of these products are so drastically such a poor value, it’s extremely difficult to see the values of each bar in the third picture, so we figured we would cut out the products that aren’t used often due to availability or reliability issues so you can really see the details of the data. 

Waterfall Graphs Of All Products Tested

A Waterfall Graph is a graph that shows traditional frequency response on the X and Y axis, but also adds time to the Z axis. This shows you frequency response over time, and in our case, translates to the resonance decay of the panel we are testing. While much more time consuming to really pick apart, this is the best data to look at to see which product truly is best. Feel free to click on the photos for full resolution and download them to compare however you chose. 

As you can see, ResoNix may appear to come at a premium price. But the overall value is unbeatable. ResoNix CLD Squares are not only the most effective product, but it's also the best value overall out of any of the products that have been tested by Chris so far.
Stop spending more money and spending more time when you can do it better and quicker and cheaper overall with ResoNix CLD Squares.

As of today (April 17th, 2023), these are the only products that Chris has tested. This will be updated as he releases more testing results.

But What About The Tools Used To Install Sound Deadener?

I’m sure you didn’t expect this one. Yes, the tools you use to roll on your constrained layer damper sound deadener can in fact effect its performance. In the past couple of years, some of these less than reputable amazon-based brands have been selling sound deadener rollers that are patterned. These patterned rollers have been marketed to be good, or cool locking, etc. But the truth is, they actually decrease the performance of the product you are installing. 

The reasoning for this is pretty simple. A constrained layer damper works by using the visco-elastic properties of the butyl to create shear forces against the panel and Aluminum Constraining Layer. These shear forces are introduced as the panel bends when it vibrates. The strength of the aluminum constraining layer, and its overall structure have an effect on its ability to act strongly against the butyls shear forces, or, if a compromised constraining layer, can allow for “wiggle room.”

When rolling your sound deadener with one of these patterned and ridged rollers, you do two things that negatively affect its performance. First, you are stretching the aluminum constraining layer, making it weak and unable to provide proper resistance against the shear forces of the butyl. When putting pressure on this product as you are rolling over it with these ridged and patterned rollers, the aluminum layer is unable to move separately from the butyl, so it much stretch. Second, you set the aluminum constraining layer up in a way that has many stress-relief indents. Think of it like an accordion. For a CLD to perform at its best, we need to have the aluminum constraining layer unable to easily open. Using a flat roller, think of the end result as the accordion stretched all the way open. It is already fully open and is unable to stretch any further, and this will have the greatest resistance to opening up any further. But when you introduce these ridges from the ridged rollers, it acts as the accordion is closed and it has plenty of relief to move around and open up freely. When you do this to your constrained layer damper, the panel it is adhered to will be able to flex more due to the constraining layer having much more relief. 


Below are the test results of a particular product installed with a normal, flat roller, a roller that has small ridges, and a roller that has more aggressive ridges. 

The smooth roller reduced resonance by 10.25db. That same product was removed, and a new piece was installed and tested again with the Noico ridged roller. Note, the ridges on this roller are very small, but they do affect performance. This roller reduced resonance by only 9.75db. This isn’t much, but is definitely measurable and repeatable. The more aggressively ridged roller that seems to be sold under many different brand names on Amazon is a different story. This one reduced resonance by only 7.5db. This is just shy of a 3db difference, making the product almost 2x less effective vs when rolled with a normal roller.