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Sound Deadening (CLD) Testing

779K views 2K replies 210 participants last post by  TOOSTUBBORN2FAIL 
#1 · (Edited by Moderator)
So like many other people, I'm tired of wondering what CLD ACTUALLY works best. So I've decided to test a whole spectrum of them, using an accelerometer, so this can be put to rest. This will take between 1-2 months to start, but may be drawn out over time if people want continuing results from new products, etc. Once I have the test rig set up, it wont be that hard to test.

As of right now, I plan to build a box out of baltic birch. It will have two removable baffles, both secured with 10-32 screws, and hurricane nuts. The front baffle will hold two speakers, which will remain unchanged throughout the testing. This will be HAT L6SE's. There will be two front baffles, one completely sealed, aside from speaker mounting holes, and one with two 2" vent holes. The reason for this, is that a sealed box will cause different levels of vibration than one that is just measuring structural vibration, and I want both measurements.

The back baffle will be 22ga 12" squares of mild steel. There will be a new piece of steel for each different CLD. The reason is, removing this stuff could result in bends, and that could change resonant frequency of the baffle. So each CLD test will get its own piece of metal, and each will have before and after measurements, so that deadener effectiveness can be seen as a percentage. I will also post the frequency response of each test, if possible (I need to check one what kind of output I can get from my O-Scope, more on that by friday). Each panel will be bolted on at a set torque with a calibrated torque wrench, to keep that from being an issue. The piece will have a 1/2" perimeter to be bolted down to.

Each CLD piece will be weighed, measured, and photographed multiple times pre and post installation. I may also take video of each test. Samples will all be 6x6" squares, just a tad bit over 25% coverage. Testing will be done indoors, and will be temperature controlled.

I'm open to durability testing, but using the oven is out. New house, and not quite ours yet, means thats not going to happen. I have a torch, but thats a little inconsistent. It does get ridiculously hot here in the summer, I could save all the pieces, then leave them out when its 110 degrees for a week or so.


Once I've gone through the testing to "rank" the deadeners, I will move on to some intall technique tests/alternative deadening techniques tests. Things such as seeing what kind of differences to expect going from 25% coverage to 50% coverage, etc. I'd also like to test using small pieces vs on large equal area sheet. I've seen it suggested that small pieces randomly spaced works just as well, I'd like to prove or disprove that. Then I'd like to test bracing, and bracing+deadening, etc.


If anyone has an input, feel free to let me know. I'd like to get this issue settled.

If anyone wants to donate products, they are more than welcome, I'll post in the first post what I have, and whats been donated, and by who, unless they wish to remain anonymous. All I ask is that pieces donated are 6x6" squares or larger.

I've updated what people might be able to send so far. I want to make sure no one feels any pressure or rush, the soonest I forsee being able to start actually testing is the beginning of May. When I get products in, I'll move them to the corresponding area. I will also start to build the test enclosure this weekend.


Dynamat xtreme - 1 12"x12"
GTMat Pro 50 Mil - 1 12"x12"
GTMat Ultimate 80 Mil - 1 12"x12"
GTMat 110 Mil - 1 12"x12"
GTMat Onyx - 1 12"x12"
Alphadamp - 1 10"x14"
SDS CLD - 1 6"x10"
Stinger Road Kill Pro - 2 6"x6"
Lightning Audio Deadskin - 1 8"x8"
StP Bomb - 1 sheet
StP Gold - 1 sheet
StP Silver - 1 sheet
StP Vizomat - 1 sheet
Peel N Seal - 1/3 Roll

Things that are on the way or have might soon be on the way

Fatmat
second skin damp pro
edead
possibly some cascade V-2
possibly some knu concepts stuff

That leaves me wanting for the test

cascade vmax
maybe some raamat
 
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#3 · (Edited)
So what will be your standard of consistency per CLD piece?
A specific and consistent weight, or a specific and consistent dimension?
Other than that it appears your attempt at removing as many variables as possible is on the right path.
You could even go as far as making sure the ambient temperature is the same during each test since as you say, it will take months to complete which will bring you well into summer. :)
Maybe you could use a spreadsheet to make data comparison from one piece to the next easier since it's likely that the number of test samples will be well into the dozens?
Just a thought.


I look forward to your results :thumbsup:


Bret
PPI-ART COLLECTOR
 
#7 · (Edited)
IDGAF - I'm actually really hoping to add some products like Peel n' seal and other ashpalt based products. I'll pm you in a little bit.

Bret - Good point on sample consistency and temps, I'll add that info to the first post. I will most likely do a spreadsheet and update it as I go. I'm also hoping to overlay frequency response charts so that it is simple to read and see the actual differences before and after for each sample.

Danno14 and GLN305, I'll pm you guys in a little.

First post updated.
 
#9 · (Edited)
I can donate Alphadamp. How many 6"x6" pieces do you need?

You say you will be using 1 in your (initial) test plan. But, for example, if you decide to change the baffle material in mid-testing, you will need more samples.
 
#10 · (Edited)
Chithead and astrochex, that would be awesome, pm me and we'll work it out. Astro, 1-2 pieces would be enough.

You say you will be using 1 in your (initial) test plan. But, for example, if you decide to change the baffle material in mid-testing, you will need more samples.
Thats a good point. I think for sure that the first tests would be with one 6X6" sheet, using the 22ga steel. However, I would like to compare different percentages of coverage at a later time, so maybe a 6X6" and a 10x10" sheet. But I'll honestly be happy with anything people can donate.
 
#12 ·
Fantastic. Do you have any info about the accelerometer? I'm just wondering if some are designed for certain scales, like fine small movements vs longer movements.

I don't hear much about tiles falling off from heat, but if you do then I'm sure you can find a little $10 toaster on CL. Regardless, hope it goes well.
 
#15 · (Edited)
I'll pull it out later and post up everything I can on it. I actually plan to test it this weekend. It was actually a present from my dad, specifically for this testing. If it turns out this one wont work, I will pick up one that will, like the one listed by Dean. My dad will be helping me set up the electrical side of things, and building a power supply so that the amp voltage is consistent.


As far as heat goes, that's more for the asphalt tiles.






Edit - Accelerometer is a SainSmart ADXL 335. 3 axis, mini board, very light weight. I was worried about weight affecting the readings. After I test it, I'll decide whether to use it for this test, or if I need to pick up another one. I may end up needing to pick up another one, as this one only goes from 0.5-550hz on the z axis. I'd rather have more than that, even if vibration fades away before the upper limit.
 
#14 ·
Any body have any idea about this company and their MLV, they only do Home sound proof projects, no CLD or CCF used or sold by them. The bad is you need to buy a whole roll of 100Ft, the good is the price is good and it is in my area. The specs seem okay, 1lb per square foot of 1/8 thick. Anybody from this area that want to split a roll assuming it is a good product? :) I am not sure I will use this on the doors maybe some parts but not all, more than anything I want it to eliminate road noise, floors and real wall or trunk.
Mass Loaded Vinyl
 
#16 ·
I can't seem to edit my first post anymore, so here is the current list.

Products that may be coming

Rattletrap
Raamat BXT
GTMat Pro, Onyx, Ultra
Misc STP-Atlantic products
SDS CLD
Alphadamp
Stinger Roadkill Pro

Products in my possesion

1 SDS Tile
1 Lightning Audio Deadskin Tile
1 Alphadamp Tile
 
#20 ·
very interested to see the testing methodoligy you use here.

all the tests that don did on SDS before he started selling product.

dissolve test
heat test
cold test
vertical\horizontal\upside down

including your accelerometer test

i wanna say he did them all using a 1"x1" square on a piece of sheet metal.
 
#26 ·
Ya, it took him a bit to get back to me. I emailed him on a Thursday, hadn't heard back by Monday, re-emailed him and he got back to me the same day. He said he is super busy.

All things considered it took about a week and a half between my initial email and him sending me my order. I did place a large order and had a ton of questions though.
 
#25 ·
Really? I emailed him two weeks ago on Wednesday, received a reply back from him Thursday morning, paid that afternoon, and order was shipped out that evening. Was very quick response and shipping.
 
#30 ·
This is an interesting experiment and I put some effort into one very similar, though smaller scale. I've always wanted to do something more inclusive and a little more serious though. I would really enjoy collaborating on this experiment.

This report from E-A-R Specialty Composites is one of the most accessible resources I found on the subject. It is written in very simple terms and is easy to read, but has some great details about how CLD works and what is important when considering them.

This report from Roush Industries is more technical but illustrates a simple method for determining the damping factor of a system graphically without using expensive software or hardware (you already have an accelerometer, just plug it into a spectrum analyzer like TrueRTA or REW).

You mention using a 'scope for measurements, but I believe the best method is a spectrum analyzer and calculating the damping factor as discussed in the article above. I have cleaned it up a bit and summarized the method in my experiment and it can be found here in the beginning of my build thread.

You mention using 22ga sheet metal. I'm not sure it would be the best test substrate. Most sheet metal in a car is much thicker, no? I realize that thicker material is substantially more expensive, but it is a very important factor. The effectiveness of a CLD is significantly related to the thickness of the substrate vs the thickness of the stiff backing (aluminum in most cases).

-J
 
#31 ·
You mention using 22ga sheet metal. I'm not sure it would be the best test substrate. Most sheet metal in a car is much thicker, no? I realize that thicker material is substantially more expensive, but it is a very important factor. The effectiveness of a CLD is significantly related to the thickness of the substrate vs the thickness of the stiff backing (aluminum in most cases).

-J
Most floors and rockers average between 16ga and 18ga but I think 20ga - 22ga is about average for door thickness. I know 22ga is what most body shops use for welding panel repairs on the newer cars. It will differ from car to car or truck but I would think it should be fine for this test.
 
#38 ·
Chris,

Good to see you taking on this potentially monumental task. You know I am local, so if you ever need a "lab assistant" just give me a call. I'd be happy to come help you out with any of the fabrication or testing. I can bring along what photo equipment I have to try and help document, if need be. Which shop locally were you going to attempt to score some deadener from (you can just name a street/area if you don't want to name names)?

On a personal note, I would love to see the Knu Konceptz Kno Knoise and/or Kno Knoise Kolossus tested. I have tried a couple of times to get a hold of Don at SDS and never gotten a response. I plan to purchase from Knu myself, but haven't placed the order yet. If I can order soon, I'll see what I can do about slipping in an extra sheet to the order to pass along.
 
#39 ·
Thanks Dustin. I haven't stopped by any shops yet, but I figured I would see what Zam's was using. I was going to try to get some dynamat from California Car Stereo, but Tracie from GTMat sent me a square, although I'd really love to find some Dynaplate. I'm not spending $175 on it though, and that seems to be the cheapest it goes for, since they only sell larger quantities. If you have any extra Knu stuff, that would be great. If not, we'll see where the budget falls.

Photo help would be great, my camera works, but its still a point n shoot, although it takes 1080 video. I think it does video better than pics.

Tracie, I got your package today, thanks again for helping out.

So, what I have so far is,

2 - Stinger Roadkill Expert Tiles
1 - SDS CLD Tile
1 - Alpha Damp Tile
1 - Lightning Audio Dead Skin Tile
1 - Dynamat Xtreme Tile
1 - GTMat Onyx
1 - GTMat Pro 50 Mil
1 - GTMat Ultimate 80 Mil
1 - GTMat Pro 110 Mil



Jazzi, when I get some more time, I'm going to PM you. I was hoping to meet up at Bings grand opening, but just saw you wont be able to make it.
 
#45 ·
#41 ·
I'm going off the sticky notes in the package I got. I'll go over each product as I test and email each company if I need more info. I know I need to email Lightning Audio, as I can't find any specs on their products.

I just checked out Audio Technix site, I'd definitely like to test their products, especially being that they have different constraining layer thicknesses than everyone else. I'll be emailing Second Skin as well, as they also have their own thicknesses on the constraining layer.
 
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