Sound Deadening (CLD) Testing
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I've been doing a lot of work, but mostly silent, as I've been trying to get together money to pick up a better accelerometer. But it doesn't look like that's going to happen. Just don't have the budget right now. The problem with the current accelerometer is it doesn't have the signal to noise ratio to pick up the full range from 20-500hz. I was thinking of eq'ing the response to get it to work, with a note in the results that that had been done, but the speakers, amp, and power supply cant handle it. From 90hz to 70hz the response drops 30db. I have about a 20db range the accelerometer will pick up. I would need 20db more head room, but that would put everything I have way past its safe range. At the least, I would need a subwoofer, and a better power supply.
That said, testing has actually begun. I've been dialing in the setup for the last weekend, and actual final results will be coming tomorrow. Unfortunately, the microphone is the only measurement device I have for this at this point. It will be placed as it has been shown in the pictures, however it now has a jig that holds it in the same place every time. I'll be using the Omnimic mic, and REW for results. I'll have both frequency response, and waterfall graphs. REW is soo much easier to overlay graphs than Omnimic is.
I will be starting with the asphalt based products, only because they clean off of the metal the easiest. And with that...........I will now give my SUBJECTIVE opinions on the products, based on cutting them out, handling, etc. Keep in mind, this is only subjective, and not based on results from testing with the mic.
Peel N Seal - One of the thinnest feeling constraining layers. Aluminum seems to be coated, I'll follow up with a polish test. Definitely has a smell to it that butyls don't. My wife knew exactly when I opened the box. Has a good backing paper. Cut relatively easily.
Alphadamp and SDS CLD Tiles - The butyl seems similar in both cases. The aluminum is also thick in both, just a tiny bit thicker on the alphadamp. That said, I expected them to both cut similarly, and especially with alphadamp being 20mil thinner overall. That said, alphadamp was significantly more difficult to cut. I'm going have to ask what grade of aluminum brands are using now, because that's the only thing I can think of that would make it that much harder to cut. Both these products are two of only 3 products that could support themselves while just holding the corner of the sheet.
Dynamat, Stinger Road Kill Expert, and GTMat Onyx - All three are very similar as far as butyl consistency. They all have the most sticky butyl of any of the products, almost oozing. The backing on dynamat and road kill is paper based, and sticks well. The onyx backing is a pretty thick plastic, and sticks well. All cut similarly well.
GTMat 50mil, 80mil, and 110mil - All three had thin constraining layers. There has been some speculation by some that the constraining layer is not actually aluminum. I will be testing this. It seems very similar to the Peel N Seal layer, and it is definately coated in something. The backing paper is not up to par with the others, its a very thin plastic layer, but at least with the samples I received, it doesn't seem to stay in place very well.
Lighting Audio Dead Skin - By far the lightest feeling product in the test. Also seems asphalt based. Also has the worst backing paper, it seems to want to fall right off. Its possible that this sample is old, but I'll test it anyways. Looking around, I couldn't find any specifications for it anywhere.
STP Vizomat - This is an oem type free layer damper. It was very easy to cut. Plastic backing, that sticks well. The website says its a bitumen product, which is a form of asphalt, but there is no smell.
STP Gold and Silver - Both products are an butyl products, gold having both a thicker constraining layer, and butyl layer. It seems very stiff for the constraining layer thickness, and has an embossed pattern in the constraining layer.
STP Bomb - This is the thickest product of the whole group. It is also the third of the products that can support its own weight by holding the corner. It also seems very stiff for the constraining layer thickness. This is also a mastic-bitumen based product, but like vizomat, has no smell.
Knu Konceptz Resonance Control and Kolossus - Both products are butyl based. Both have decent back papers, and seem to cut well. I haven't had much time to play with either, but I have a large amount of both, so I'll post more as I get a better impression of them.
That said, testing has actually begun. I've been dialing in the setup for the last weekend, and actual final results will be coming tomorrow. Unfortunately, the microphone is the only measurement device I have for this at this point. It will be placed as it has been shown in the pictures, however it now has a jig that holds it in the same place every time. I'll be using the Omnimic mic, and REW for results. I'll have both frequency response, and waterfall graphs. REW is soo much easier to overlay graphs than Omnimic is.
I will be starting with the asphalt based products, only because they clean off of the metal the easiest. And with that...........I will now give my SUBJECTIVE opinions on the products, based on cutting them out, handling, etc. Keep in mind, this is only subjective, and not based on results from testing with the mic.
Peel N Seal - One of the thinnest feeling constraining layers. Aluminum seems to be coated, I'll follow up with a polish test. Definitely has a smell to it that butyls don't. My wife knew exactly when I opened the box. Has a good backing paper. Cut relatively easily.
Alphadamp and SDS CLD Tiles - The butyl seems similar in both cases. The aluminum is also thick in both, just a tiny bit thicker on the alphadamp. That said, I expected them to both cut similarly, and especially with alphadamp being 20mil thinner overall. That said, alphadamp was significantly more difficult to cut. I'm going have to ask what grade of aluminum brands are using now, because that's the only thing I can think of that would make it that much harder to cut. Both these products are two of only 3 products that could support themselves while just holding the corner of the sheet.
Dynamat, Stinger Road Kill Expert, and GTMat Onyx - All three are very similar as far as butyl consistency. They all have the most sticky butyl of any of the products, almost oozing. The backing on dynamat and road kill is paper based, and sticks well. The onyx backing is a pretty thick plastic, and sticks well. All cut similarly well.
GTMat 50mil, 80mil, and 110mil - All three had thin constraining layers. There has been some speculation by some that the constraining layer is not actually aluminum. I will be testing this. It seems very similar to the Peel N Seal layer, and it is definately coated in something. The backing paper is not up to par with the others, its a very thin plastic layer, but at least with the samples I received, it doesn't seem to stay in place very well.
Lighting Audio Dead Skin - By far the lightest feeling product in the test. Also seems asphalt based. Also has the worst backing paper, it seems to want to fall right off. Its possible that this sample is old, but I'll test it anyways. Looking around, I couldn't find any specifications for it anywhere.
STP Vizomat - This is an oem type free layer damper. It was very easy to cut. Plastic backing, that sticks well. The website says its a bitumen product, which is a form of asphalt, but there is no smell.
STP Gold and Silver - Both products are an butyl products, gold having both a thicker constraining layer, and butyl layer. It seems very stiff for the constraining layer thickness, and has an embossed pattern in the constraining layer.
STP Bomb - This is the thickest product of the whole group. It is also the third of the products that can support its own weight by holding the corner. It also seems very stiff for the constraining layer thickness. This is also a mastic-bitumen based product, but like vizomat, has no smell.
Knu Konceptz Resonance Control and Kolossus - Both products are butyl based. Both have decent back papers, and seem to cut well. I haven't had much time to play with either, but I have a large amount of both, so I'll post more as I get a better impression of them.
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Thanks for the update Chris. Sorry I haven't really been around to help. Seems like the last few weeks have been crazy, and this weekend will be no different. I might have some time in the evenings starting next week, just shoot me a text when you might be working on this and I'll do my best to swing by and help.
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Thanks Dustin, its been pretty hectic here too. Just finalized the refinance on the house last week, drama at work that could lead to termination for some people for breaking certain laws, and trying to get ready for promotional testing and interviews. Seems like when one thing ends, another starts up. To top it all off, I started riding to work again this morning, and lost a shoe to a pitbull on the way. I was lucky my wife mad me wear my skate shoes, because if I was in running shoes, it would have ripped me off the bike. Found out later animal control put it down after it killed another stray.
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So, my calipers and micrometers are eluding me tonight, (probably at my sister in laws), but there is at least one deviation from published specs so far. This one is so blatant that its visible. After reading published specs for Knu Konceptz Kolossus, I had to re-look at some things. Mostly, comparing its constraining layer to Alphadamps. Both advertise as having a 10mil thick aluminum constraining layer, but Alphadamp was significantly more difficult to cut. I went back and cut a small sample to tear apart and measure. Before removing the butyl from the aluminum, I tried flexing both, and had my wife do the same. The conclusion was both of us thought the Alphadamp was much stiffer. I then started pulling the butyl from the aluminum (took about 10 mins per sample, for about a 1" square section). The Alphadamp is definitely thicker than the Kolossus. Since I don't have a way of objectively measuring until tomorrow, I'll just say for now that it seems like the Alphadamp aluminum is 3mil thicker. If Alphadamp's aluminum is truly 10mil thick, that would put the Kolossus aluminum at 7mil, which is the same as what Knu advertises its cheaper (20% cheaper) Resonance Control line as having.
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Ok, got my calipers. Alphadamp measures between 9.5-10.5mil. Stp-atlantic's Bomb measures 4mil (stated thickness is 100 microns, or 3.9mil). Kolossus measures 7mil, BUT that is with a protective plastic film covering the aluminum. I couldn't peel it off at work very well, but that film is between 1-2mil thick. When I get home, I'll get the film off and measure just the aluminum. Remember, stated thickness is 10mil.
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Subscribed. Looks to be interesting.
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Definitely an interesting find! I would definitely like to know the difference between the standard Kno Knoise and the Kolossus. Are they both using undersized constraining layers? Do they both use the same constraining layer with the Kolossus simply using a thicker adhesive layer? (7 mil is the stated thickness of the standard Kno Knoise after all.) And of course the most important question, how do they perform? Really looking forward to the results of the testing.
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So they are definitely using undersized constraining layers on both products. I haven't been able to get the plastic layer off, next step is to try chemicals. Its very slick, and the best tweezers I have won't grab it firm enough to peel it off. So, with the plastic film still in place, the Kolossus constraining layer averages 7mil thick, instead of the 10mil thick advertised. Resonance Control averages 4mil thick with the plastic film in place, instead of 7mil thick as advertised. Keep in mind, they are claiming the aluminum layer is 7mil and 10mil thick respectively, saying nothing about a plastic film.
I'm going to try a couple of things tonight to get the film off and get a final measurement, and then email them, but I'm not sure I'll get an answer. I know both myself and rton20s emailed them about participating in the testing, and never got a response.
I'm going to try a couple of things tonight to get the film off and get a final measurement, and then email them, but I'm not sure I'll get an answer. I know both myself and rton20s emailed them about participating in the testing, and never got a response.
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Plastic film is cheap so I can see using it to protect the aluminum; it obviously doesn't work as a constraining layer and should not be used to help bring up the mil for advertising purposes.
How is the accelerometer coming? I have been thinking about other ways to measure the flex. There are distance measurement photo eyes, or something I work with a lot is a cam/spring with an analog sensor. Not sure how accurate the readings would be with a regular DMM, but just wanted to throw out a couple things I've been thinking about.
How is the accelerometer coming? I have been thinking about other ways to measure the flex. There are distance measurement photo eyes, or something I work with a lot is a cam/spring with an analog sensor. Not sure how accurate the readings would be with a regular DMM, but just wanted to throw out a couple things I've been thinking about.
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Yep, its not that the film is a problem, unless they are padding their numbers with it. But even with the film padding the numbers, they're still 30% and 43% off of the numbers they claim for constraining layer thickness. I'm really curious if they'll respond to a query about that, and what it is they'll say. Based on published specs, it theoretically should be a front runner, and rton20s purchased some to test after trying to see if they would donate a sample for it.
I posted a few posts up about the accelerometer, but basically the one I have now isn't going to be good enough. There are two ways to fix it, replace it, or eq the response, as GOYOP and my dad had suggested. Unfortunately, some things fell through for my wife, so I'm not able to pursue either option, as eq'ing the response enough to work puts the power supply past its abilities, and even if it was up to the task, it would be putting the speakers significantly past the safe point, both thermally and excursion wise. I would need a high excursion sub to get it to work.
At this point, I'll be using the mic, as Jazzi did in his project log, just in a more controlled environment. I'll have to get both frequency response of the bare metal, and damped metal, and waterfall plots of both. I'll have the first set of results to post tomorrow. I wont be able to test friday as I have testing for a supervisor position, but I will be testing sat and sun as well. I may have some raamat coming, if so that will be the last of the products to be installed on the roof of my car for long term heat testing.
Do you have any links or search ideas for the alternate measurements? I'd like to still look into it (who knows, I may get the position).
I posted a few posts up about the accelerometer, but basically the one I have now isn't going to be good enough. There are two ways to fix it, replace it, or eq the response, as GOYOP and my dad had suggested. Unfortunately, some things fell through for my wife, so I'm not able to pursue either option, as eq'ing the response enough to work puts the power supply past its abilities, and even if it was up to the task, it would be putting the speakers significantly past the safe point, both thermally and excursion wise. I would need a high excursion sub to get it to work.
At this point, I'll be using the mic, as Jazzi did in his project log, just in a more controlled environment. I'll have to get both frequency response of the bare metal, and damped metal, and waterfall plots of both. I'll have the first set of results to post tomorrow. I wont be able to test friday as I have testing for a supervisor position, but I will be testing sat and sun as well. I may have some raamat coming, if so that will be the last of the products to be installed on the roof of my car for long term heat testing.
Do you have any links or search ideas for the alternate measurements? I'd like to still look into it (who knows, I may get the position).
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Update,
KnuKonceptz Kolossus - Constraining Layer thickness, no plastic film - 4mil - Advertised as 10mil
Knukonceptz Resonance Control - Constraining Layer thickness, no plastic film - 3mil - Advertised as 7mil
I'll prepare an email tomorrow morning.
KnuKonceptz Kolossus - Constraining Layer thickness, no plastic film - 4mil - Advertised as 10mil
Knukonceptz Resonance Control - Constraining Layer thickness, no plastic film - 3mil - Advertised as 7mil
I'll prepare an email tomorrow morning.
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wow I'm surprised that knu would do that there products are normally pretty decent.
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also you may want to try and call and talk to them. i was able to get thru to make an order for wire and have them replace a defective fuse block and they were very helpful and immediately sent new part.
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I was thinking at first it was quality control. It still could be, but it also seems it could be cost cutting. Its less than half the thickness its supposed to be. Being that they claim to manufacture their own products, im really curious to see what they say.
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yeah me too and it makes me wonder about their other products
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I've used some of their RCA cables, power wire and distro/fuse blocks and was much less than impressed. It all felt cheap and the RCA's fell apart, cable pants weren't glued and the signal wires weren't shielded and much smaller conductors than normal. Only bought from them once and probably never will again. Just my $.02
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