Stuart already showed a screenshot. But there is a lot more in the Powerpoint Doc. All stuff we know but very nicely presented IMO. The file is too big to post here, so if anyone wants it, ask me via real email [removed] DDI'd love to see that report if you can find it. I appreciate your above post.
Homasote Test
Originally posted at johnlsayers.com, topic 21932.
Thanks for that link, Stuart.......I'll look it over today.
Regarding any insulation performance enhanced effect from RC, I brought that into the discussion because of a minor statement in an NRC-CNRC document that I've had kicking around for quite a while that has always nagged at me. I have highlighted that passage in this link:
Steve
Uh, I am confused. On page 1 of this thread I inked a thread from 15 years ago regarding sub 100 Hz TL performance of walls from IR 761. In the table I put in there it shows an 11 to 16 point improvement in STC from the addition of RC. Assuming you read that, what is your question? AndreRegarding any insulation performance enhanced effect from RC, I brought that into the discussion because of a minor statement in an NRC-CNRC document that I've had kicking around for quite a while that has always nagged at me. I have highlighted that passage in this link:
I definitely read all of that data, Andre, and I do apologize for beleaguering this point.
It's just that one line in that NRC-CNRC report that has always nagged at me....."Adding resilient channels to one face of a single row of studs improves sound reduction considerably, allowing the sound absorbing material in the cavity to be effective." That seems to imply that the insulation will not be as effective without the RC.
So the specific question is.........is the optimal performance on the insulation in the cavity in any way dependent upon the presence of resilient channel?
Steve
Thanks for the clarification. Expanding/adding/re-enforcing my first post on this sub topic, as shown in fig 5 of NRC 44692 there are 2 parallel paths for sound through such partitions. Each type of sound isolation address different paths. As a sadly humorous related isolation issue is floating floors (AKA why doesn't my floating plywood floor with 20 Hz springs and 2" air space not do anything for lows?}. AndreIt's just that one line in that NRC-CNRC report that has always nagged at me....."Adding resilient channels to one face of a single row of studs improves sound reduction considerably, allowing the sound absorbing material in the cavity to be effective." That seems to imply that the insulation will not be as effective without the RC. So the specific question is.........is the optimal performance on the insulation in the cavity in any way dependent upon the presence of resilient channel?
OOh! I know the answer to that! It's because you didn't sprinkle enough magical pixie dust on the plywood! :) 8) :shot: (I'll show myself out the door, now....) OK, getting back into more serious things (because light-weight floated floors really are a joke! :) ) ... Steve, your comment was from the NRC article, where it says: "Adding resilient channels to one face of a single row of studs improves sound reduction considerably, allowing the sound absorbing material in the cavity to be effective." You added your own comment: "That seems to imply that the insulation will not be as effective without the RC." It's a little cryptic, but when you take that in the context of the paragraph right above it, they are talking about a wall with NO decoupling first (just drywall on both sides of studs: "...gypsum wall board is solidly fastened to the wood studs both sides..."), as compared to a wall with RC on ONE side ("... adding resilient channel to one face of a single row of studs...."). The implication here seems to be that the insulation is not effective when the drywall is "firmly fastened", but is effective when it is decoupled. That ties back to the second paragraph in the article, which says: "... if the two faces are of the wall are not isolated from each other, sound absorbing material in the cavity is rendered ineffective". Thus, they are not really saying that it is the RC that makes the insulation effective, but rather that it is the fact of decoupling (or not) that makes it effective, no matter how it is accomplished. RC is just one method. However, there's still the issue that they didn't explain what they wanted to say very clearly. The way I see it, is that they just did not word that very well: The insulation will still do what it always does (damping resonances in the cavity) regardless of whether or not the drywall is decoupled. However, the fact of having a solid mechanical connection between the faces has a negative effect that counteracts the positive effect of the insulation. Not decoupling doesn't somehow prevent the insulation from damping: it just means that the damping isn't very useful, because the coupling is really bad. Simple analogy: you can pour water into a bucket with huge holes in it all day, but the bucket will never get full because of the holes. That doesn't mean that you are not pouring in water like crazy! It just means that the holes are thwarting your efforts. Plug the holes, and all of a sudden your efforts are far more "effective" at filling the bucket. You are still filling it the same way, just something else is negating that. And inside the wall, the insulation is still damping resonances, but the coupling through the studs negates most of the effort. That said, I'm not sure I'd agree that there is no effect at all from having insulation in a coupled stud wall: there is an effect. But it would be much larger if one of the leaves was decoupled. Take a look at page 30 of IR693, for example. The same full-coupled wall assembly (one layer of 16mm drywall on each side of 62mm metal studs, 400 mm OC) without insulation in the cavity shows Rw of 36, and with insulation that rises to between 40 and 43 (depending on type of insulation). That's a significant increase, so the insulation is having an effect.. just not a huge effect. So there is an effect... the effect is just not as "effective" as the effect would be if the drywall was decoupled. (That's a confusing sentence, for sure! effectively...). Not sure if I'm explaining that sensibly or not. To me, it seems that the article is just poorly worded. It's not that there is no effect at all: just that the usefulness of the effect is overpowered by the coupling. (I'm hoping Andre can summarize the above into 10 concise words or less...)(AKA why doesn't my floating plywood floor with 20 Hz springs and 2" air space not do anything for lows?}.
Simple answer? No. :) (I bet even Andre can't be more concise than that!) - Stuart -is the optimal performance on the insulation in the cavity in any way dependent upon the presence of resilient channel?
I can not better what you wrote. You are the master of expansive explanations. Andre(I'm hoping Andre can summarize the above into 10 concise words or less...)Simple answer? No. :) (I bet even Andre can't be more concise than that!)is the optimal performance on the insulation in the cavity in any way dependent upon the presence of resilient channel?
Perforated caps, if I remember correctly, are used to give a little more volume to the sound.That's very interesting! Thanks, Andre! Great find. Any idea what they mean by the sample being a "perforated plug"? In what way was it "perforated" Rachat crédit Isolation ? Is that something to do with the test procedure, or did it have holes in it? It would be great if they would repeat that test for a broader range of frequencies. There's some interesting hints in there, but more data would be nice. I'm intrigued... - Stuart -