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Post by handude on Sept 7, 2017 19:17:43 GMT
Hi all, New to this forum. I have been planning on making some soffit-style bass traps for my home studio (dimensions are 16'' L, 16'' W, 47'' H. Yup... very similar to GIK Soffits.) My question is this: does rigid fiberglass of 1.6pcf density perform similar to those "pink fluffy insulations" when it comes to 16'' thick or thicker bass traps? A lot of you guys are suggesting that using the pink fluffy insulation is the way to go, so just curious if something like this will work well too. Knauf Earthwool Insulation Board with ECOSE Technology
It seems like the 3.0pcf version of this is considered a great alternative to Owens Corning 703, so I assumed that if I use their lower-density versions like 1.6pcf, it will perform to a very similar extent for soffits and superchunks. I already have a lot of their 3.0pcf boards in hand, but am also open to purchasing the 1.6pcf versions if you guys think they will in fact work better for low-end absorption at this thickness. Please vote and share your opinions! Looking forward to the results!
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Post by Hexspa on Sept 8, 2017 0:12:02 GMT
I don't think 1.6pcf is better than 3.0, in general, and I don't think fluffy is better than 1.6pcf.
I think it comes down to price/performance ratio for a given thickness.
I haven't done any first hand tests but, from what I understand, past a certain thickness, the ratio tapers toward "fluffy is 80% as good as the nearest rigid equivalent"; but I've been wrong before.
Also remember that 12 4" panels are better than two 24" panels. I know you're making soffits but the same detail is likely to apply: when deciding on material, also consider coverage in your cost assessment.
Thanks.
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Post by handude on Sept 8, 2017 1:50:45 GMT
Thank you Hexspa for your response.
So are you suggesting that from the performance standpoint alone (disregarding price), 3pcf rigid fiberglass will never be worse than 1.6pcf or fluffy, if not better? Also some people like Avare from Gearslutz are actually suggesting that past a certain thickness, pink fluffy or other low density fiberglass will outperform OC703 and equivalents... But at the same time many others suggest to just stick with OC703-type fiberglass for 16'' thickness. My understanding is that past a certain thickness, low frequencies have harder time travelling the entire depth of the OC703 trap due to its density, get reflected back instead of absorbed, and eventually will begin to perform worse than pink fluffys or low-density fiberglass. (has to do with Gas Flow Resistivity I heard.) So like you say, if OC703 is still better than the other options, why are so many people saying that pink fluffy or something like Roxul Safe 'n' Sound is the way to go? Is it simply from the price/performance ratio point of view? Not that they are actually better at that thickness?
And yes I am aware that area coverage is as important as the thicknesses of the traps. In fact I'm considering building at least 12 of those aforementioned soffit traps to take care of the front two corners (2 soffits each), the two rear corners (again two soffits each corner), and the 4 remaining soffits will likely go to the wall-ceiling corners.
To me, price is not really a deciding factor for making those soffits because I know I will save lots of money compared to buying the pre-made ones anyways. To me at this point, I think it's more about whether pink fluffy/low density fiberglass will outperform OC703 or get close to OC703 rather. If it actually outperforms, then of course I will be going with those fluffys or 1.6pcf fiberglass boards. If they only get close like you mentioned, then I do not see any reason to use the low density materials because price is not much of a concern to me right now.
Thank you again, and looking forward to hearing others' thoughts on this as well! This topic is definitely fun.
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Post by Ethan Winer on Sept 8, 2017 15:18:42 GMT
Andre Vare (Avare) is correct, and you can always follow his advice. I'm not sure where the exact transition falls, but once you get to 8-12 inches thick fluffy fiberglass is at least as good as rigid, and might even be better. I'll add this very important note: a soffit trap only 16 inches on each side is nowhere near as effective as one that's larger. Even if you made it 24 x 16 so it doesn't hang down any farther, that will increase bass absorption 50 percent. Or considered another way, it will extend the full 1.0 absorption down half an octave lower.
How are you planning to frame these and contain the fiberglass? When RealTraps sold soffit traps we used white cardboard, the type used for shipping boxes but not the really thick kind. Then people could paint them to match as needed.
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Post by Hexspa on Sept 8, 2017 20:09:41 GMT
As I admitted, I don't have first-hand experience comparing among the various types. I do use some fluffy but in a super-chunk form factor which only has a percentage of thickness beyond the 8-12" cutoff. I also use 4" mineral wool panels but that's all I can vouch for. I apologize for any misinformation or confusion. I'll be more careful next time Thanks.
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Post by handude on Sept 8, 2017 22:12:29 GMT
Andre Vare (Avare) is correct, and you can always follow his advice. I'm not sure where the exact transition falls, but once you get to 8-12 inches thick fluffy fiberglass is at least as good as rigid, and might even be better. I'll add this very important note: a soffit trap only 16 inches on each side is nowhere near as effective as one that's larger. Even if you made it 24 x 16 so it doesn't hang down any farther, that will increase bass absorption 50 percent. Or considered another way, it will extend the full 1.0 absorption down half an octave lower. How are you planning to frame these and contain the fiberglass? When RealTraps sold soffit traps we used white cardboard, the type used for shipping boxes but not the really thick kind. Then people could paint them to match as needed. Thank you very much Ethan, your expertise is always a great help! I wish I had more space in my room so then I could build even bigger traps like you suggested. However I know that area coverage is also very important when it comes to bass trapping, so I guess I will stick to 16'' x 16'' x 47'' designs for now. Here is my plan: -Grab a 4-foot 1''x2'' pine wood and have them cut into four 46'' lengths in order to form the four long edges, and get some 1/2'' plywood and get them cut into 16'' x 17.5'' squares to cover the top and the bottom. That way I end up with an exterior dimensions of 16''x17.5''x47'' when everything is put together using wood screws and some corner braces. All cut at a local Home Depot. -For containing the fiberglass, I am planning on using some 65% polyester, 35% cotton BROADCLOTH. I thought this kind of fabric should be fine for bass trapping. another option I'm considering is POLYESTER LINING. Which one do you think would be more appropriate? -For fiberglass, I am undecided between two products: 1.6pcf Knauf Earthwool Rigid Insulation Board with ECOSE Technology like the one mentioned on my very first post, or those so-called pink fluffy insulation. GIK Acoustics says on their DIY section that those 1.6pcf Knauf boards are excellent for making bass traps and they also seem to use those knauf boards for their ready-made panels and bass traps too so I thought it would be a very good choice. Or, if you think that pink fluffy will perform better at 16'', which specific model do you recommend in general? (When you say pink fluffy, you're referring to those Owens Corning Pink-Panther ones right? There are so many different type of those pink ones...) Would the 1.6pcf Knauf boards be dense enough to hold their form when stacked up 46 inches? Or should I implement some type of support around mid-height instead? I assume that if I use those pink fluffy insulation, I will definitely need to implement support inside, or else it will not be able to support its own weight and compress which is what you don't want. -How about Roxul Safe 'n' Sound? Are they really that dusty and hard to work with? Thank you again Ethan, and everyone else. Seungwoo
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Post by Hexspa on Sept 9, 2017 8:24:52 GMT
I wish I could be of more help.
I decided not to test between fluffy and rigid because I wanted to save my cash and get to work on other things.
In the meantime, I'm going to guess that fluffy's the answer.
The reason is because of extensive echoing of the "use fluffy past 8" sentiment, never seeing anyone use 16" thick rigid and have seen people installing thick fluffy at the rear of a room.
Plus all that rigid is going to be expensive and heavy.
Thanks.
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Post by handude on Sept 9, 2017 14:20:31 GMT
I wish I could be of more help. I decided not to test between fluffy and rigid because I wanted to save my cash and get to work on other things. In the meantime, I'm going to guess that fluffy's the answer. The reason is because of extensive echoing of the "use fluffy past 8" sentiment, never seeing anyone use 16" thick rigid and have seen people installing thick fluffy at the rear of a room. Plus all that rigid is going to be expensive and heavy. Thanks. Hey Hexspa, Thank you very much for helping out. You are right. I guess pink fluffy should be just fine for this application, plus it will be even more money-saving compared to something like a 1.6pcf fiberglass board. Three questions to ask you... if you are still happy to assist 1. I'm looking at homedepot.ca right now to shop for some pink fluffy (Owens Corning of course), but there are just way too many choices. QuietZone, R-12, R-14, R-20, R-24, R-31, R-40, and the list goes on and on... Man I am so lost For bass trap application such as my 16'' design, which one do yo think will do the trick? 2. Would you recommend adding some sort of support for the fluffy at the mid-height of the frame design, in order to prevent it from compressing downward? 3. Fabric question... would 65% polyester, 35% cotton broadcloth be a good choice for bass traps? What about 100% polyester linen? Yes I would love to use GOM Anchorage or FR701 but those things are just too expensive and shipping to Canada is ridiculous too! And please do NOT recommend burlap Again thank you, and also looking forward to hearning Ethan's thoughts.
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Post by Nigel Spiers on Sept 9, 2017 17:37:18 GMT
Hi,
Fabric - 100% Polyester fabric works very well, is inexpensive and available in all fabric stores in a range of colors. It is inflammable and has good stretch which means you can get a tight, quality surface with no sagging even after many years. Make sure you test the fabric by breathing thought it prior to purchase.
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Post by handude on Sept 9, 2017 18:58:57 GMT
Hi, Fabric - 100% Polyester fabric works very well, is inexpensive and available in all fabric stores in a range of colors. It is inflammable and has good stretch which means you can get a tight, quality surface with no sagging even after many years. Make sure you test the fabric by breathing thought it prior to purchase. Thank you Nigel!
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Post by Hexspa on Sept 10, 2017 4:10:11 GMT
I wish I could be of more help. I decided not to test between fluffy and rigid because I wanted to save my cash and get to work on other things. In the meantime, I'm going to guess that fluffy's the answer. The reason is because of extensive echoing of the "use fluffy past 8" sentiment, never seeing anyone use 16" thick rigid and have seen people installing thick fluffy at the rear of a room. Plus all that rigid is going to be expensive and heavy. Thanks. Hey Hexspa, Thank you very much for helping out. You are right. I guess pink fluffy should be just fine for this application, plus it will be even more money-saving compared to something like a 1.6pcf fiberglass board. Three questions to ask you... if you are still happy to assist 1. I'm looking at homedepot.ca right now to shop for some pink fluffy (Owens Corning of course), but there are just way too many choices. QuietZone, R-12, R-14, R-20, R-24, R-31, R-40, and the list goes on and on... Man I am so lost For bass trap application such as my 16'' design, which one do yo think will do the trick? 2. Would you recommend adding some sort of support for the fluffy at the mid-height of the frame design, in order to prevent it from compressing downward? 3. Fabric question... would 65% polyester, 35% cotton broadcloth be a good choice for bass traps? What about 100% polyester linen? Yes I would love to use GOM Anchorage or FR701 but those things are just too expensive and shipping to Canada is ridiculous too! And please do NOT recommend burlap Again thank you, and also looking forward to hearning Ethan's thoughts. I agree with Nigel that stretchy fabric can produce a clean result, though it tends to be a bit more expensive than muslin (which is what I'm currently using). The whole key to fluffy is size. You want to get the dimensions that minimize the number of layers, wastage and helps create evenness in construction i.e. no odd parts and/or extras. I've gone over fluffy prices forwards and backwards and you will not save money by buying one size or another. Even different brands like Johns Manville only come in different R ratings and lengths. But, when you add it all up and compare, the price is the same. The only way to save money is to buy in bulk, on sale or used. If you want to build 16" traps then go with a 16" fluffy. This one seems right for you. Remember that insulation is meant to go between studs and joists and not into soffits and superchunks so you'll have to work within market demands for dimensions. Also, I don't think you'll save any money - perhaps on the contrary - by buying unfaced insulation. Strangely, I think faced is cheaper. You'll have to tear off the facing (no fun) but you can always use the facing to improve your results, depending on your design. I used supports at every layer in my super chunks and I don't regret doing so. Supports can be something as simple as wire wrapped around nails to create a firm net. Whatever you do, don't use jute twine! Hope that helps.
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Post by handude on Sept 10, 2017 14:03:51 GMT
Hexspa, thank you. Jeez, I have just so many questions... I assume you're using pink fluffy in your superchunks as well? (24'' front face triangle?) Would you agree if I said, the only difference b/w something like 1.6pcf Knauf Earthwool Insulation with ECOSE Technology (OC701 equivalent) and pink fluffy would be price? Because if OC701 equivalents will work just as well as those pink fluffy, I would actually prefer to use them instead so I wouldn't have to worry about self-compression and collapsing. So basically, the R-value does not have any relationship to the density, and thus not relevant to the gas flow resistivity? Also curious to find out what muslin is like. Don't you find muslin a little fragile and also too easy to see through? Seungwoo
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Post by Hexspa on Sept 10, 2017 22:58:16 GMT
Hexspa, thank you. Jeez, I have just so many questions... I assume you're using pink fluffy in your superchunks as well? (24'' front face triangle?) Would you agree if I said, the only difference b/w something like 1.6pcf Knauf Earthwool Insulation with ECOSE Technology (OC701 equivalent) and pink fluffy would be price? Because if OC701 equivalents will work just as well as those pink fluffy, I would actually prefer to use them instead so I wouldn't have to worry about self-compression and collapsing. So basically, the R-value does not have any relationship to the density, and thus not relevant to the gas flow resistivity? Also curious to find out what muslin is like. Don't you find muslin a little fragile and also too easy to see through? Seungwoo Yes, I'm using fluffy. The faces are more like 31" but it's 24" rigid cut diagonally. I wouldn't agree that the only difference between rigid and fluffy is price because I honestly don't know. I've never compared identical form factors with identical placement. I'll hypothesize that they're significantly different. R value is technically resistance to heat transfer (I think) but it's essentially a linear relationship to thickness assuming the density is the same (which it is). Muslin is cheap but it works. You can search my threads or view some of my vids on YouTube to see what I have. The muslin-covered panels are natural white - I had previously used blue and red fabric. You can see through it but it's not like that's a bad thing. I can only see through my super chunk facing but not on my rigid panels. Probably has to do with light having somewhere to go. It looks fine on my rigid panels. It just depends on what kind of look you want and how much you want to spend. My budget was limited so that's what I used and I'm happy with it. I wouldn't say it's fragile but it isn't kevlar either. I dropped my bike on one of my super chunks and it tore a hole. On the other hand, when my cloud panel fell, it poked into an RFZ panel and it didn't tear but it did indent my mineral wool. These are acoustic panels, after all and not flak vests or riot shields so I'd say durability, while a concern, isn't primary. Thanks.
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Post by Ethan Winer on Sept 14, 2017 19:25:37 GMT
I apologize for any misinformation or confusion. I'll be more careful next time Not at all! The problem is that nobody knows the answer for sure. At least nobody I know. As far as I'm aware, nobody has ever actually measured this stuff properly. So all the "experts" (and many are) at Gearslutz and elsewhere are mostly going by this fellow's software that guesstimates the absorption based on gas flow resistance: whealy.com/acoustics/Porous.htmlMe, I need real empirical evidence - measurement data - before I take anything like acoustic absorption as fact. So for now I'll go along with, and pass along, the advice that when an absorber is very thick you can get away with less density. And less density might even be better at one foot thick and thicker. It makes sense.
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Post by Hexspa on Sept 15, 2017 20:12:39 GMT
I apologize for any misinformation or confusion. I'll be more careful next time Me, I need real empirical evidence - measurement data - before I take anything like acoustic absorption as fact. Agreed. I'm not going to get into any vehicle that theoretically could - but has yet to - pass crash testing. My opinion is especially substantiated by my own measurements being in direct opposition to "rules of thumb" like lengthwise angled panel placement where SPL is loudest and extensive rear wall treatment; at least in this room with the actual quantity and type of treatment coupled with my specific needs. Thanks.
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