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Discussion Starter #221
Great job! Very interesting to see those plots. According to the graphs the CLD's seems to remove ringing in the midbass area but increases it slightly in the lower frequencies. The immediate resonance is lowered in amplitude and the Fs seems to move down in frequency with a lower/wider Q. I assume all CLD's behave more or less in this fashion?

May I suggest you start another thread when the testing is complete? It's much easier to find the first post of the actual testing than searching through 10 pages ;)
I will definitely be making a results thread once testing is done. I'll make everything look nice and easy to compare.

There is definitely a difference in the way certain CLD's behave. I wasn't sure there would be, but I just tested another, albeit an asphalt/butyl hybrid, and its results are very different.


Beckerson1, I can test that if you'd like. I can also test adding it to a current CLD aluminum layer. I actually bought a 16mil thick aluminum sheet, that I plan to epoxy to alphadamp after measuring alphadamp by itself, to see what that does.
 

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Discussion Starter #222
Just caught on to this now. What an excellent project, stubborn, kudos for all your hard work.

I wonder, have you considered using a hall effect transistor for measuring your panel vibrations? Rather than attaching several magnets and a large-ish accelerometer-and-cable assembly, you would simply attach a small magnet to the resonant surface and place the hall-effect transistor close to it. This approach has proven to be very effective:
Magnetic Levitation (Hall Effect) - YouTube

The fact that you are using steel as your resonant surface could be an issue with this idea, however, as the coupled magnetic field may introduce non-linearities or harmonics in the measurement. But, it's worth considering.

Accelerometers are very noisy. Replacing the caps to increase bandwidth will cause the undesired effect of introducing time-based noise into your measurements. Even with multi-sample smoothing, I'm not sure there will be enough resolution in your measurement data to confidently arrive at a conclusion.
I'll have a chat with my dad about that, he will be in town tomorrow. Looking at some info on my own, it seems to agree with the possible issues in using it with a steel surface, but I'll see what he can add.

Dustin, check out the newest results. GTMat 80mil, it behaves completely different than the Knu 80mil product did.
 

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Discussion Starter #223
GTMat Ultra

ACTUAL TESTING

Total thickness - 80mil

Constraining layer thickness - 2mil

Approximately 0.44 lbs per square foot

Notes - I measured this product and peel n seal at the same time. Both had a constraining layer thickness of about 2mil. Both have a plastic layer in between the butyl/asphalt mix and the aluminum, with a total thickness of 5mil. The aluminum layer on GTMat IS aluminum. There has been some debate tonight, however, the aluminum layer polishes identical to peel n seal, weighs the same as peel n seal, and behaves the same. It does seem to be low grade, but it IS in fact, aluminum. Constraining layer thickness is off about 0.5mil from spec, but that's not that bad. If Knu's product was off 0.5mil, I don't think anyone would be complaining.

Bare Metal Frequency Response


Damped Metal Frequency Response


Overlay of Undamped Metal Vs Damped Metal Frequency Response


Bare Metal Waterfall


Damped Waterfall
 

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Discussion Starter #224
Resonance Control Overlay


GTMat 80mil Overlay


Resonance Control Damped Waterfall


GTMat 80mil Damped Waterfall




I video'd the entire measurement process, those will be up tomorrow. For reference, when measuring, REW shows a headroom number. Undamped metal headroom on the resonance control test showed around 5.3db. Undamped headroom on the GTMat test showed 5.2db. Damped resonance control headroom was around 16.8db, vs 9.0db for GTMat. That's a peak resonance reduction of around 11.5db for the resonance control, vs 3.8db for GTMat.
 

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Glad to see this is underway Chris! Would you mind to add the summary like that to the end of each test?

IE:
Peak resonance reduction ~ X.Xdb
Damped headroom ~ X.Xdb
Very much appreciated!!!
 

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Glad to see more results filtering in. If you would like some assistance this week, I can probably be available on Thursday evening or Friday afternoon/evening. I think Saturday is out though, as that is my son's birthday.

I'm definitely interested to see how the unique characteristics of how each product affects the metal panel. When looking at just the first two results, it does appear that both products are having similar effects. The Knu just seems to be the superior product of the two tested. I'm excited to see how this all plays out. And I wonder how many manufacturers are secretly, anxiously awaiting the results of their test.
 

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Thank you sir for all your time and effort! This is great information that will benefit many companies and consumers! Once again - thanks!
 

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Discussion Starter #230
I messaged them to see what size their samples were, to make sure it would work. I suppose I need to call them.


Dustin, thursday is shot, I have a 45 min interview for the supervisor position friday right after work, so most of thursday I'll be relaxing. Friday I'll be testing on and off all day though, so whatever time works for you after say, 2:30, just text me.
 

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Discussion Starter #232
I havent tested it yet, but it will probably be done tonight. Subjectively, it seems like a dynamat xtreme clone. Same gooey, extremely sticky butyl feel, same or maybe a tad stiffer aluminum layer. Odd backing paper choice with plastic instead of paper, but a much better product than their asphalt lines.

I have STP Atlantic's Bomb lined up to test when I get home.
 

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I will definitely be making a results thread once testing is done. I'll make everything look nice and easy to compare.

There is definitely a difference in the way certain CLD's behave. I wasn't sure there would be, but I just tested another, albeit an asphalt/butyl hybrid, and its results are very different.


Beckerson1, I can test that if you'd like. I can also test adding it to a current CLD aluminum layer. I actually bought a 16mil thick aluminum sheet, that I plan to epoxy to alphadamp after measuring alphadamp by itself, to see what that does.
Ya I'm curious how much it would effect things. I mean its very thin (probably close to 1-2mm.

Most areas I have double thickness.
 

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Is it possible to also test how easy it is to remove it and document it? assuming that needs to be done on every test or a mistake is made while installing it. It would be nice to get an idea. I know dynamat and 2nd skin hold up very well and are also easier to remove if needed.
 

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Discussion Starter #238
I'm not sure how one would objectively measure this, but I have been subjectively keeping track. Believe it or not, so far, Peel N Seal was the second biggest pain to remove so far, after SDS CLD Tiles. Both Resonance Control and GTMat removed easier and cleaner.
 

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Discussion Starter #239
STP-Atlantic Bomb

Total Thickness - 4.2mm (I will measure my sample tomorrow)

Constraining Layer Thickness - 3.9mil (measure tomorrow)

Approximately 1.49 lbs per square foot

Notes - This stuff is monstrous. Heavy, thick, and stiff. It is an asphalt based product, however it does not smell like the Peel N Seal, or the GTMat. It also has tested the best so far.

Bare Metal Frequency Response


Damped Metal Frequency Response


Overlay of Undamped Metal vs Damped Metal Frequency Response


Bare Metal Waterfall


Damped Metal Waterfall
 

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Nice, the StP Atlantic stuff is one of the brands I was really interested in. I'm curious to see how their other products compare.
 
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