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Sound Deadening (CLD) Testing

780K 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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#74 ·
#77 ·
Just an update on where things are. There will also be durability testing for heat, using a small toaster oven. I'll use an oven thermometer to get the temps accurate. The test box is being built as we speak, I sourced a local shop for the cutting, since all I have is a router. I'll cut the holes at home, and glue it hopefully by Tuesday. I'll also be getting the metal today to make the stamps. I'm going to make two, one for the actual testing, and one small one for the heat testing, that way size doesn't play a factor into heat failure. I've also ordered new capacitors for the accelerometer board, as the stock ones limited bandwidth to a -3db point of 50hz. The new ones will have a -3db point past 640hz.

Testing size is updated, the test surface total area is going to be 11"x11". The metal piece itself will be 12"x12", and the outside half inch perimeter will be used to clamp it down. The test squares will therefore be 5.5"x5.5", to maintain quarter coverage. This works out, as SDS has a 6" width, but the butyl stops a about 3/32" before the aluminum does.

I'm working out with my dad how to show the results. There may be two options, and when we confirm that, I'll post here, and want to opinions of everyone that donated. I had wanted to show loss factor using the Half Power Bandwidth Method as mentioned before in the thread, but the more I look into it, and the more I talked to my dad, the more I decided against it. The main reason being that it can only determine loss factor at the resonant frequency of the damping system, and it also seems that recently studies have shown accuracy to vary by large amounts at low frequencies, and high loss factors. To be honest, I doubt any products here will create a critically damped or over-damped system, but it will still be nice to know how close to critically damped we can get.
 
#84 ·
There will also be durability testing for heat, using a small toaster oven. I'll use an oven thermometer to get the temps accurate.
Is the goal of this test to show dampening performance after temperature exposure or to see the effects of extended heat exposure on the materials?

What is your target temperature?

You are doing a helluva a service to the community, thanks.
 
#79 ·
Your exactly right. Basically, I need a way to excite the metal. I'm not happy with hitting it with a hammer, as its not repeatable. So I figured I would build a box, with an inside height and width of 12"x12", looking from the front, made from 1/2" baltic birch. So outside dimensions would be 13"x13", again looking from the front. The front would have a 13"x13" baffle, with a 11"x11" square cut out. This is the mounting point for the metal test piece. It will have 8 hurricane nuts, 4 at the corners, and 4 in between, so I can get accurate torque each time the piece is removed and replaced. The test metal will be 12"x12", and will be sandwiched between that front baffle, and another identical 13"x13" baffle with the 11"x11" cut out.

Move onto the back, and you'll have a rear baffle, just like the front. To attach to that and provide vibration, will be the speaker mounting baffles, utilizing 2 L6SE's, mounted motor side out, to make wiring easier.

I hope that helps, if not, I'll try to sketch something up. I'm horrible at using computer sketch programs, so give me a little time to draw it up. If that fails, I'll take a pic of my hand drawings lol.
 
#80 ·
I think I got it now. I think one speaker would be enough, but this might prove wrong during testing or depending on how sensitive is the accelerometer. Plus it would more accurately represent the volume of air per average door (average door also has one woofer compressing the air).

I'm not sure if the graphs curve will change curve angle based on level of power applied to woofer (for the same CLD tile), what do you think?
 
#82 ·
That's one of the things I plan on testing before actually moving on to the comparison. I plan on testing power levels, and trying to see whether the frequency response will look the same connecting the dots from test tones, as it does from white noise. I have this nagging feeling that it wont, but that's one of the things I'll find out.

My reason for using two was more to make sure the driver stays linear, as depending on the power level we arrive at, 20hz will likely push one driver past linear, which could affect results. But, that is another thing I can test. It may affect results the same in each case, which then wouldn't matter. In the end, I don't think I can fully represent what would happen in a door, which is why I'm more focused on eliminating as many variables as possible, and testing products themselves head to head.

A lot of people on another forum were wanting me to do these tests in an actual door, or with a cut out piece from a floor board, but I wouldn't be able to make sure the products were applied evenly each time, which bugged me, aside from every car being different. I know Erin had thought about doing something with accelerometers and deadening, and I think these are the reasons he never pursued it further. That's why I'm trying to stick to products and application, without applying it towards a certain vehicle.
 
#83 ·
I'm out of town at the moment, but I might be able to find a few minutes to model the enclosure for you this evening. It shouldn't take me all that long to knock it out since it is the kind of work I do every day. I got that the box would be 1/2" Baltic birch and 13" x 13", but do you know how deep you planned to make it?
 
#85 ·
Dustin, the internal dimensions are 12"x12"x12". The baffles front and back are 3/4" baltic birch, the four sides are 1/2". So, four sides, each side piece is 12"x12.5". I didn't want to do two 12"x13" and two 12"x12" pieces to keep everything equal. Probably wouldn't have had an effect, but you never know. Then the front baffles attach, making the box 13"x13"x13.5" Those front baffles are 13"x13"x3/4", with an 11"x11" cut out.

Astrochex, the oven will be for durability testing. I'd love to do heat related tests of vibration, but I'd need a much bigger oven to get the test size pieces in it. It is something I'd like, just can't afford to do right now. There is a guy at work with plans to build a oven for powder coating, depending on what happens with that, maybe I could do it down the road.

Target temp for the durability testing will be once at 200 degrees, and once at 400. Set for 30 minutes each, and video them, so I can see if and when they fall.
 
#86 ·
I'm glad to hear that you are doing the temp tests for durability. Your nose might be a guide when it comes to determining failure point. :D

I think that if you were going to do a vibration at temp test series, you would be making a consistent test process a challenge.
 
#88 ·
That was my worry with it too, is consistency. Without being able to have a chamber to put everything in, including the accelerometer, it would be too hard to keep temps consistent. There is definitely a huge difference in smells though, even at room temps.



Dustin, no worries. What program were you going to use?
 
#87 ·
Thanks for the figures Chris. Headed back from the NSRA show in Bakersfield now. Probably watching the fights tonight, but I'll see if I can find a few minutes to knock out at least the model enclosure tonight.
 
#89 ·
I'll probably just do it in Sketchup. It is really quick for knocking out simple models like this. I have some Autodesk software at home as well, but Sketchup is quicker and easier.
 
#90 ·
Here is a quick model that I threw together to see what the test enclosure will look like. The foreground shows the two pieces that will clamp the metal panels to the enclosure. The background shows the opening for the Hybrid Audio Technologies L6SE. As I have more time, I will model the driver as well as all of the fasteners (including hurricane nuts) and show some exploded views. However UFC 159 starts in just a couple minutes, so this is it for now.

 
#91 ·
That's awesome Dustin, thanks. Yep, that's pretty much it. The front baffle will be able to be changed as well, so I can test one vs two speakers, to see what I need to stay within the accelerometers sweet spot.

I picked up the metal as well for the stamps and press plates for applying the deadening. Three x 12"x12"x.25" steel plates. One 4' section of 1.5"x1.5" square tubing to brace the plates, and to stamp the durability test pieces out. One 3' section of 1"x.25" steel strap, for the cutting edges of the press. Hopefully I can weld it all together next weekend and try it out.
 
#92 ·
If you need someone to weld it up for you, just let me know. My brother could knock it out really quick at his place in Tulare.
 
#93 ·
Dustin, that might work best. The guys I have to weld are umm, sketchy at best. Difficult to get the time to get something done, or in the case of one of them, it will take 4 hours to do a 10 minute job. Let me know when you get some time and we can figure it out.

I forgot to update the list, so here it is. I got another sample of GTMat Pro, and 1/3rd roll of peel n seal in. Thanks to those who sent it in.

Ok, this is the list of have in my hands products.

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
 
#94 ·
I won't be available this weekend as I'm trying to make it up to the Simplicity in Sound open house. Otherwise just shoot me a text and I can coordinate it with my brother. If you don't have my number, just PM me.
 
#95 ·
I was really hoping to head up there too, but my dad signed a lease for a shop in Oxnard, and I'll be helping him take the furnaces and evaporator down there Saturday. That should give me this week to get the box made, and next week to get the metal done.
 
#97 ·
Crap that reminds me. I never got that Cascade stuff in the mail to you. Sorry, completely slipped my mind. I am also very interested in the results of this with a new ride to fix up now. The new one is a Lexus tho and my feelings are it will require a whole lot less than my previous rattle box. Let me know if you still want me to mail you some and how much you need again. I just looked and I have quite a bit left actually but it is almost 2 years old in my garage so hope that doesn't affect things negatively.

On a side note, I picked up some Alfadamp to try out this weekend. Couldn't wait due to the awesome sale which ended yesterday. Should have it to use in a couple weeks. Parents are going to pick it up in Montana for me and whenever they get up my way I'll have it and I can start getting to work.
 
#99 ·
predope sale; 50 % off pretty much everything. I only grabbed one 20 sqft pack but that should at least do the front doors which will be needed with my Morel 8s pounding them eventually with 340 Mosconi watts on them:cool: I think that pack worked out to about $80 or so and shipping was very reasonable - they sure have changed that for us Canadians - thanks alot Ant:D even if I chose to get it sent to Montana this time anyways. I also grabbed 100 ft of 16 ga and some 16 ga quick disconnects as well for the hell of it. It will be nice to have three runs of different looking wires on each side for the 3 way front. I probably have enough good wire already but this will be the third car these have been in and there are several areas on each line that have been soldered which I am sure affects the sq in some way. If nothing it will be easy to figure out which line is for what speaker:D
 
#100 ·
Sorry for the lack of updates, had a parent in the hospital. I did get to box built, and got a power supply for the amp and source unit for the speaker I'm using the excite the panel. I'll be soldering on the new cap's to the accelerometer board later this week, and then starting to test things out and get a feel for the measurements I'll be getting. I also got the toaster oven for heat testing, so I'll move forward with that this weekend. I fired off an email to all companies for whom I have product from, asking for MSDS sheets, product specs (some aren't publicized), and the best way to remove in case the need arises.

After talking with my dad, I'll be skipping the RTA for accelerometer date acquisition. I'll be using the o-scope and manually importing the data over. After talking with my dad, this is the method which he felt would produce the most accurate, repeatable measurements, and avoids relying on Fourier transform math, which he believes adds another variable. In his explanation, he showed me the model of a computer generated sound, one of them made with Fourier transform math, and one made with FEA modeling. The sound was supposed to be that of air blowing through an aluminum tube. The FEA generated sound sounded very life like, almost real. It also took 6 hours for his computer to go through all the calculations. The Fourier transform sound did not sound right. If I had to compare, it would be the sound of the voice programs, where they sound almost metallic. It was however, much simpler and quicker to put together (probably why this is as far as most people venture into it).

That said, if anyone is good with Labview Signal Express, and wouldn't mind walking me through it, that might be able to save some time. Its not a very intuitive program, and my dad never bothered to learn since National Instruments doesn't document anything in it very well (and expects you to pay for their training). My dad is working on a program in C, to automate the process of taking measurements, but it probably wont be ready by the time I'm wanting to start.


James, ya if you can send it that would be great. I was looking on parts-express for the price of buying some, and they want around $60 minimum, as you have to buy a good amount of it.
 
#101 ·
Sorry I never got with you on Friday about the metal work. Ended up being a crazy day for me. Let me know if this Friday might work for you.
 
#102 ·
No worries at all. I actually didn't end up doing anything this whole weekend, my mom ended up in the ER friday afternoon. Shes gotta get more tests done this week.

This friday should be good, I should actually be able to hook up everything and test it out by then, after that its just figuring out documentation, and getting the pieces cut and ready.
 
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