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Post by Hexspa on Apr 26, 2016 5:38:42 GMT
Here's a crazy idea: let's say my room has 2/3 dimensions within "golden". What if I was to stack cinder blocks up to the ceiling (lol) and modify my room's dimensions by creating a reflective surface? Maybe put insulation behind those blocks? Surely stone bricks have more reflectivity than drywall...
Too good to be true?
-m
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Post by Rock on Apr 26, 2016 12:38:58 GMT
I believe you're right. That will effectively (and actually) change the room dimensions but the reflectivity is probably not much different at all but the lowest freqs.. Practically speaking, I think it might be cheaper and easier to just build a drywall partition but that's up to you. Insulation inside a wall cavity will damp resonances, so in the case using drywall, might be more effective than with the cinder blocks but will probably have only a small influence in either case. For the small cost, it makes sense to install fluffy while you're at it...But...
This sounds like a hypothetical discussion so I think a better idea, if this partition is a back wall, is to fill the entire wall with absorption as deep as can be afforded (space wise); the deeper, the more effective at lower freqs.
Even if you change room modes to more even distribution, you'll still have room modes and absorption will always be needed.
BTW, regarding transmission from room to room, cinder or concrete blocks being more massive might yield better STC but they would need to be mortared in place and all gaps caulked. But if "lesser STC" walls, ceiling and floor, would allow the sound to "flank" around the higher STC concrete wall.
Cheers, Rock
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Post by Ethan Winer on Apr 26, 2016 15:59:13 GMT
When dealing with a room in a home, I usually suggest making an entire wall of absorption rather than a wall of sheet rock. So if you determine that your length is two feet too long for the width and height, stuff 24 inches of fluffy insulation behind a frame along the entire back wall. Even if a room has "perfect" dimensions, it still needs a lot of bass traps. So while I've never measured one versus the other, I'll bet at least $100 that 24 inches of fiberglass gives a better LF response than a new bare wall built 24 inches into the room. This also keeps the room larger because you'd have to give up even more space for bass traps after building the new wall.
--Ethan
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Post by Hexspa on Apr 27, 2016 0:02:01 GMT
Thanks guys. So no glorious walls of cinder. I've been looking into "pink and fluffy" now for a few days. It seems most effective when being less dense, having less gas flow resistivity, used on very low frequencies and is better applied in depths greater than 8". Is there a particular kind of fluff I should be investigating? Should it be left in rolls or laid out flat then fluffed and layered with supports between (as not to compress the bottom layers?) www.homedepot.com/p/Owens-Corning-R-19-Kraft-Faced-Insulation-Batts-23-in-x-93-in-BF42/202585869www.homedepot.com/p/Owens-Corning-R-13-Kraft-Faced-Insulation-Batts-23-in-x-93-in-BF11/202585859^ Those look like the most suggested options. If I use Kraft paper variants should my traps be "directional" in the sense that only 1 side gets paper (the loudspeaker side) or is kraft-faced not suggested for this type at all? Looks like rolls are definitely cheaper than batts. Ethan, you mention building a frame. I'm guessing maybe either one huge room-sized frame with slots of chicken wire that accommodate one layer of R-13/R-19 or maybe doing a "modular" approach similar to your 2' corner traps which can then be stacked or arranged next to one another. Lastly, I'm guessing with 2' of pink fluff at my rear wall I won't be needing corner panels either in front or behind this mass of fluff. Or is this another case of "more is always better" and to treat the rear wall as normal (rear corners, flat surface with rigid/air gap combo at RFZ point) then build a fluff barrier between the difference of dimensions or is that overkill? Thanks again, -m
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Post by Rock on Apr 27, 2016 12:57:51 GMT
Based on Ethan's suggestion, here's the first plan that comes to mind: Frame the wall 2' on center studs with top and bottom plates. The frame will be used to staple the FG and front fabric. Lay out un-faced rolls or bats* behind the frame**. (it might be easier to install the plates first, then layout the un-faced FG, then install the studs but IDK, use your judgement). OK, at this point, you could cover the frame with fabric but wait. If you built the space behind the frame to accept 2' wide batts/rolls, you still have 3 1/2" of space between the studs. You can staple 3 1/2 FG ***vertically in this space. On the side edges, use kraft paper facing the room. Also cut kraft faced FG for the top and bottom of each stud space. Use 3 1/2" un-faced in the center section for broadband absorption.
*Roll VS Batt? Check prices by converting to cost/unit volume and buy the cheapest.
**I don't think the compression of the batts/rolls is a problem (I could be wrong) except that you'll need a little more FG. If it is a problem, your chicken wire shelf is a good idea. You can stack up the FG and when you see it start compress, install "shelves" as needed.
***It might be better (Ethan?) to use OC703/705 for the front with the FRK on the edges and un-faced in the center. Cost will be more but since it's more commonly suggested, it may be preferred?
In any case, this is one idea, there may be better...
Cheers Rock
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Post by Hexspa on Apr 28, 2016 3:13:17 GMT
Thanks Rock. I have virtually no proper construction experience. Maybe these images will help. Is this a top plate? And 24" on center: Additional image: What I wanted to make was something like this: In a roughly 2' size so I can stack em. Or maybe make one dimension 4' so I can just stack two high and they'd be more portable. I wasn't planning on busting out the heavy lumber and nails but if you think that's better then I should consider it. Keep in mind I'm not going to have a saw or workspace suitable for wood. Any cuts are going to be made by a Home Depot associate.
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Post by Rock on Apr 28, 2016 12:12:49 GMT
Yes, the top and bottom "plates" are the horizontal pieces (usually 2x4s) to which the vertical "studs" are "toe" nailed (or screwed).
Not having tools is a big handicap. To build a frame partition wall, you really need to cut the lumber on site if you want a close, tight (interference) fit. Your idea of making portable boxes is nice but a wall will use less material. Using screws allows for disassembly if needed. A circular saw, tape measure, rafter square, 2 saw horses, and clamps are all you need for the cuts. A drill/driver and screws to assemble. A stud finder will help you locate ceiling joists to attach your top plate to the ceiling.
Cheers, Rock
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Post by Hexspa on Apr 28, 2016 21:41:02 GMT
Yes, the top and bottom "plates" are the horizontal pieces (usually 2x4s) to which the vertical "studs" are "toe" nailed (or screwed). Not having tools is a big handicap. To build a frame partition wall, you really need to cut the lumber on site if you want a close, tight (interference) fit. Your idea of making portable boxes is nice but a wall will use less material. Using screws allows for disassembly if needed. A circular saw, tape measure, rafter square, 2 saw horses, and clamps are all you need for the cuts. A drill/driver and screws to assemble. A stud finder will help you locate ceiling joists to attach your top plate to the ceiling. Cheers, Rock I hadn't considered building a proper wall but I can see your point. One way or another it's going to happen. Thanks, -m
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Post by Hexspa on Apr 29, 2016 0:30:39 GMT
Seriously I think I'm going to stuff, frame and stack cardboard boxes.
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