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Post by nlt6mor on Mar 8, 2017 4:16:54 GMT
As retirement nears, I am changing my home office in the the home audio/visual room. Added this year is the 4k TV, Marantz 7010, A used Rythmic subwoofer and a new paint job. Next up is to tame the bass. I really more prefer accurate sounding music concerning bass rather that being wowed with boom rattle and roll. To that end I want to reduce the nodes. I have not a way yet to measure the room, so doing this only by ear and what I read. My room is 14' wide, by 25' long with 7.5" acoustical drop ceiling. The joists above the drop ceiling is full of pink fluffy unfaced. So I think I have a rather large bass trap by default in the ceiling. My main listening position is about 38% of the room length which is about 8' from speakers and the LCD TV. First traps will be at first reflection points on either side, then I want to enclose the four from corners with traps that straddle those corners. Certainly the two vertical corners with 4 inches of 703 or Roxul board products. The floor and front wall I want to cover mainly to hide all the connections and wires. The ceiling front wall corner, I am not sure how important, but just visually to box the complete front wall. My first question concerns the two rolls of R19 you can see placed in the lower corners behind my Klipsch fortes. Again I have not measurement tools at this time, but I hear a positive change in the lower sound with those two rolls just sitting there in the plastic bags as they came from home depot. My thought is to keep them that way and start with a 2' by 2' box covered with fabric in each lower corner. Then build normal corner traps above them. Is that stupid? Can those two bags really do anything different acoustically as opposed to just straddling the 4" corner traps starting at the floor? The only gain I can understand is I would have a square corner to set my lower floor/front wall traps against as opposed to working with some angles to fit together. Hope that is understandable. IF that question is not too much I am sure I will have many more as progress is made. Thanks for any insights and suggestions. Attachments:
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Post by rock on Mar 8, 2017 4:37:38 GMT
If you mean by a "2' x 2' box" is to cover the rolls with the fabric box, consider stacking more rolls in the corners to the ceiling and just wrapping them with fabric of your choice. All 4 vertical corners can be treated like this. Your horizontal corners will require roll on their side or something else.
The above will work but if you un-package the (un-faced) FG, and build it into traps, you'll use less material and will work as good (or better?)
Check Ethan's article for measurement! It's like anything else you do with a computer... it takes some time to set up, but once you get the hang of it, you'll never regret it.
Cheers,
Rock
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Post by Hexspa on Mar 8, 2017 20:21:43 GMT
Naturally having any absorption in a corner will help improve your room's response. Like rock said, it's a matter of degree. Correct positioning and form make significant differences.
Don't be downhearted; we've all brought in some fresh fluffy, laid it down on the floor and wondered, "Maybe..."
Room looks nice. You said, "...four room corners..." and I know what you mean but rooms have 12 corners. I understand your ceiling is treated - that's great. How thick is the insulation there? 8" or thicker is ideal but having the whole ceiling treated is great as well. As a result you can subtract four corners from the equation. That leaves your four vertical corners and four floor corners left as available places for corner treatment.
If treating the floor corners is out of the question then deploying flat-surface panels (with air gap and paper facing ideally) is also an option. Extracting measurements from the room will help guide your placement and quantity of additional traps.
The room looks neat tho. If I ever retire, that looks like a room in which I'd like to spend time.
-m
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Post by nlt6mor on Mar 10, 2017 4:35:06 GMT
Thanks Rock and Hexspa for your answers.
From Rock - "The above will work but if you un-package the (un-faced) FG, and build it into traps, you'll use less material and will work as good (or better?)" I take that to mean in response to my question, that the compressed roll of R19 has no special properties that would absorb anything differently than a more normal corner trap in in that space. Correct? If no better absorbtion, then just a waste of material to leave rolled up in the bag.
From Hexspa -"How thick is the insulation there? 8" or thicker is ideal but having the whole ceiling treated is great as well. " yes the whole ceiling is insulated with about 10" unfaced. Done for heat retention purposes originally, so no air gap between the pink fluffy and the floor boards above. But I believe it is one big bass trap.
I do plan on making corner traps complete around the four corners of the the front wall. Just didn't know if worth boxing around that roll would be an absorption advantage or not. Sounds like not is the answer. The upright corner traps at the floor, I excited to use to house and hide the wires and snakes inevitable behind these 9 speaker set ups.
I do enjoy the room, just looking for guidance. Thanks
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Post by Hexspa on Mar 10, 2017 15:16:33 GMT
Thanks Rock and Hexspa for your answers. From Rock - "The above will work but if you un-package the (un-faced) FG, and build it into traps, you'll use less material and will work as good (or better?)" I take that to mean in response to my question, that the compressed roll of R19 has no special properties that would absorb anything differently than a more normal corner trap in in that space. Correct? If no better absorbtion, then just a waste of material to leave rolled up in the bag. From Hexspa -"How thick is the insulation there? 8" or thicker is ideal but having the whole ceiling treated is great as well. " yes the whole ceiling is insulated with about 10" unfaced. Done for heat retention purposes originally, so no air gap between the pink fluffy and the floor boards above. But I believe it is one big bass trap. I do plan on making corner traps complete around the four corners of the the front wall. Just didn't know if worth boxing around that roll would be an absorption advantage or not. Sounds like not is the answer. The upright corner traps at the floor, I excited to use to house and hide the wires and snakes inevitable behind these 9 speaker set ups. I do enjoy the room, just looking for guidance. Thanks Well, you could make mini soffits by making a box frame with layered supports (like a wire shoe rack) and cutting in squares of insulation laid flat. That way you get more surface area out of the insulation and maintain that box form factor you're looking for. Rock actually suggested I make this video and it's one of my more popular. In it I show the wire supports that support the insulation in my super chunks. -m |
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Post by nlt6mor on Mar 14, 2017 22:46:40 GMT
Thanks for you answers and support. So no I wont box in the complete roll. I will build a rectangle ( is that what you mean by soffit?) box with dimensions that will help accommodate mating up complete 2x4 traps along the front floor corner. I will have one trap on each side also coming back along the front walls. I can make the rectangle then just the size I need to fit all the other corner traps around it snuggly. The I will just open one roll of R19 and cut to layer into that rectangle till full. Should be no problem to leave the facing on each layer from what I read. Sound OK?
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Post by Hexspa on Mar 15, 2017 19:28:19 GMT
Thanks for you answers and support. So no I wont box in the complete roll. I will build a rectangle ( is that what you mean by soffit?) box with dimensions that will help accommodate mating up complete 2x4 traps along the front floor corner. I will have one trap on each side also coming back along the front walls. I can make the rectangle then just the size I need to fit all the other corner traps around it snuggly. The I will just open one roll of R19 and cut to layer into that rectangle till full. Should be no problem to leave the facing on each layer from what I read. Sound OK? Depends how you mean "leave the facing on". You want the facing to...face... the room. You don't want a multilayered PBJ sandwich in there. You want the crust on the outside, so to speak. Yes, by soffit I mean a rectangle that goes in a corner. Not sure if correct but words are tools not masters. Other than that sounds good. You can also consider filling the gap behind your angled panels with fluffy if you want extra effectiveness. -m |
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Post by rock on Mar 16, 2017 0:01:38 GMT
Like Hex says, you only what the facing (probably kraft paper on fluffy R19) to face out into the room. All other internal layers should be un-faced so for planning purposes, you may want to simply buy un-faced for the internal layers.
If you're going the "built-in" soffit route, you can frame the soffits with lumber then fill them with the R19. You may need wires zig-zagged to support the R19 but after it's all in place, you can staple fabric to the framing and if desired, trim the edges with thin moulding to hide the fabric edges and staples. So in the case of built-in soffits, no need to build and install panels...at least in the corners as you'll still need RFZ absorbers too. For permanent installations, I think the soffits are easier and cheaper than individual panels.
Cheers,
Rock
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Post by rock on Mar 16, 2017 0:09:12 GMT
Oh, and BTW, since you have the drop ceiling, for your ceiling RFZ, just remove and replace the tiles in the reflection zone with frames made with grille cloth, burlap or some other transparent fabric. Since you have absorption above, you're all set but you still need RFZ panels on the side walls.
Cheers,
Rock
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Post by nlt6mor on Mar 16, 2017 2:36:16 GMT
Thanks you both for your answers. Just to be clear, why not leave the face on the R19? If it is good for the front, why does it hurt in the sandwich? I am unclear why it helps lower bass absorbtion only on the face of the trap. What ever property that is, it seems like it would help as sounds bounces around in the interior of the trap.
Good Idea on the ceiling trap. I already have removed four 2x2 panels where I want to embed the atmos speakers in the joists. The front pair are about half way from the speakers to MLP. They are two grids apart. So I needed to make grille covers for the speakers, I might just as well make the cover 2x8 to cover both the speaker grids and ceiling absorption area between them. Good idea. Only problem is with an already low 7.5' ceiling height, I want to attach them as close to the ceiling as possible. Preferably right up to the ceiling. That will be tricky and require some fastener ingenuity!
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Post by rock on Mar 16, 2017 3:57:45 GMT
Just to be clear, why not leave the face on the R19? If it is good for the front, why does it hurt in the sandwich? I am unclear why it helps lower bass absorbtion only on the face of the trap. What ever property that is, it seems like it would help as sounds bounces around in the interior of the trap. OK, I don't know but here is my best guess: 1. The LF performance of a porous absorber is determined by the depth (thickness). The thicker, the lower the effectiveness. 2. The paper on the front enhances the performance of the thickness behind. 3. If there are multiple paper membrane barriers the total depth (thickness) is effectively reduced to the thickness of what is between each of the paper layers thereby reducing the LF (low frequency) performance. 4. Conclusion: One paper layer on front=good. More layers in between=bad. Honestly, I don't exactly understand the physics of why it works the way we described so I can't precisely explain but our information is based on Ethan's data; maybe someone else can explain better why the "sandwich" won't work as well. If you have other ideas, please experiment methodically and test and record your data of your ideas using our recommendations as a control and let us know. Cheers, Rock |
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Post by Ethan Winer on Mar 16, 2017 16:23:19 GMT
I don't know the physics either, but I do know that a paper "membrane" is best on only one side. Years ago my partner Doug brought some of our products to IBM's acoustics lab for testing, and one of our trials put a paper membrane on both the front and rear. I don't have the data, but Doug called me from the lab and said the absorption was terrible that way.
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Post by nlt6mor on Mar 17, 2017 21:43:36 GMT
I can probably pull the paper off the rolls that I have, not a huge issue. My soffit box will be about 16" deep and 24" wide. I can line vertical the out side layer with faced insulation. What I layer inside of that will be horizontal so the paper would be horizontal also. The would leave much area with just a paper face and 16' fluffy behind it. Just in layers. For one that does not know, I might just do it anyway, I will never know the difference. That is if the paper does not pull nicely off the insulation.
Any great ideas to hang a 2'x8' foot grille clothed within a couple inches of the ceiling? These metal ceiling grids don't leave a lot of options except some wire. Some fancy hardware I am not aware of? Thanks. This is a great place.
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Post by Hexspa on Mar 18, 2017 4:51:02 GMT
I can probably pull the paper off the rolls that I have, not a huge issue. My soffit box will be about 16" deep and 24" wide. I can line vertical the out side layer with faced insulation. What I layer inside of that will be horizontal so the paper would be horizontal also. The would leave much area with just a paper face and 16' fluffy behind it. Just in layers. For one that does not know, I might just do it anyway, I will never know the difference. That is if the paper does not pull nicely off the insulation. Any great ideas to hang a 2'x8' foot grille clothed within a couple inches of the ceiling? These metal ceiling grids don't leave a lot of options except some wire. Some fancy hardware I am not aware of? Thanks. This is a great place. The paper pulls off ok. Two hands will do it. |
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Post by rock on Mar 19, 2017 1:10:07 GMT
Right, just pull it off... But my caution was, if your two rolls will cover all your front facing areas, just keep the paper on and buy the balance of un-faced fluffy. Any great ideas to hang a 2'x8' foot grille clothed within a couple inches of the ceiling? These metal ceiling grids don't leave a lot of options except some wire. Some fancy hardware I am not aware of? Thanks. This is a great place. Not exactly sure of what your situation is but to directly cover a corner with fabric, one solution is to fasten a wood frame to the wall, "stick built" two verticals and a two horizontals, one at the ceiling, one at the floor. The neatest way is to bevel the verticals but you need a table saw to rip a bevel. You should be able to fasten the horizontals to the walls if you can't find a point to fasten at the ceiling...but you might be able to attach supplementally to the ceiling grids for added support. Staple fabric and cover the edges with finish moulding. If you can achieve the above, your fabric can be flush with the ceiling. |
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