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DIY Acoutic Panels or flower prints...

2K views 36 replies 12 participants last post by  Scott Simonian 
#1 ·
So the wife wants me to spruce up the wall behind our entertainment center and above the marty cubes. I showed her some acoustic panels and she said that there was no way I was going to glue up some foam on our walls. So what I was thinking since I have a bunch of 1.5" eggcrate stuff left I would cut some panels about 2'x4' and frame them with some 2x2 or even better round 2"pvc and then cover it all in speaker cloth or ??? Hang them up and hope they help.


So my question is would it help in any way? From my other post, I have about a 8-9db increase in spl by having the subs there versus taking the entertainment center out and putting a flat screen on the wall. I pushed the subs out about 3 feet and the spl went down.


So will this help, should I do it on both walls as I drew on the pictures below or is it a waste?


Also what does everyone use to cover these or does it not matter what you cover them with? Does the eggcrate patter go out away from or against the wall? Thanks in advance, I really don't want to put a picture frame or some decorative items there. It will minimize the power of the cubes and lower my spl by at least 20dbs, I just know it will.

 
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#2 ·
That material is too thin to do much absorbing of the mid and low frequency's, but, they will certainly absorb the high frequencies, which, in my opinion is not the best thing to do as you will have a much better performing setup by absorbing the low frequencies and mid-bass. To start, I would recommend picki g up some OC703 ridged fiberglass insulation that is 2" thick, and use two 2' by 4' sheets stacked together to form 4" thickness and place them along the first reflection points on the side walls, and also the front and rear walls, and if your wife would approve, ideally the ceiling as well.


Just so you know. You can purchase decorative fabric to cover them with!


For the really low end, you would need bass traps in each corner. I am not sure how to best DIY bass traps and make them look good, so I will let someone else advise you on that!
 
#3 ·
Thanks Marty when you say the material you mean the egg crate foam? Or the speaker grill cloth cover that I plan to use to cover them? I used a great stuff in one of my Marty subs and didn't have enough for the second one so I ordered a big role of it. I will have some extra and that is what I was going to use. Can hear the difference between this one sub with and the one without. So I was hoping it would help on the wall as well. Not that I know I needed because honestly I don't know how to tell if I needed but I just figured I would use it since I had it.
 
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#8 ·

Quote:
Originally Posted by jbrown15  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503163


Eggcrate foam is basically useless for acoustical panels IMO. Don't waste your time using it, you need a material with higher density.

Thanks for the heads up. I guess I will save it for the rest of the speakers I am building from Erich.
 
#9 ·

Quote:
Originally Posted by cessna1466u  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24499650


So my question is would it help in any way?

The egg-crate foam stuff isn't really recommended for room acoustic treatment. As Marty pointed out, it's so thin, it only attenuates the highest freqs ... which isn't a desirable trait for wall absorption.

Quote:
Originally Posted by cessna1466u  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24499650


So will this help, should I do it on both walls as I drew on the pictures below or is it a waste?

Actually, that entire area can benefit from being entirely filled with insulation.


I would not place 4" panels on the walls in that area. If I only had 4" panels, I'd span the corner diagonally with rigid 3lb fiberglass (OC703 or equiv), then cover the insulation with fabric.


Ideally, I'd fill the entire volume of that corner with insulation... as I stated above.


Our listening rooms typically need more bass trapping than thin panel treatments.


If you filled the entire area around your entertainment center with insulation, then made an aesthetically pleasing face to it, your bass clarity would increase significantly.


You can use loose fluffy insulation, but it is somewhat of a pain to work with. Or, the aforementioned 703 rigid insulation, or Rockwool, or even acoustic cotton easy touch stuff, it's all good. The best source for most such insulation, especially Owens Corning 703, is SPI, they're distributed all over the country.


Bass trapping is essential, so few HTs even employ it ... there's a lot of what's called bass trapping ... but few actually are. It's hugely impactful, very reasonably priced when DIY'ed.


Good luck
 
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#11 ·

Quote:
Originally Posted by cessna1466u  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503166


I love that Idea. Gonna check out Home Depot to see if they have the insulation.

I made some with Safe n Sound insulation from Lowe's. The material tested quite well against OC 703 back when I read up on it. Some stores only carry the 16" wide sheets, but you can order the 24" and have them delivered to the Lowe's store. I covered them with some cheap black felt called Jet Set from Jo-Ann Fabric's. The panels made a huge difference in flattening my response and a problem I was having with Audyssey setting my crossover really high.
 
#12 ·

Quote:
Originally Posted by FOH  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503246


The egg-crate foam stuff isn't really recommended for room acoustic treatment. As Marty pointed out, it's so thin, it only attenuates the highest freqs ... which isn't a desirable trait for wall absorption.

Actually, that entire area can benefit from being entirely filled with insulation.


I would not place 4" panels on the walls in that area. If I only had 4" panels, I'd span the corner diagonally with rigid 3lb fiberglass (OC703 or equiv), then cover the insulation with fabric.


Ideally, I'd fill the entire volume of that corner with insulation... as I stated above.


Our listening rooms typically need more bass trapping than thin panel treatments.


If you filled the entire area around your entertainment center with insulation, then made an aesthetically pleasing face to it, your bass clarity would increase significantly.


You can use loose fluffy insulation, but it is somewhat of a pain to work with. Or, the aforementioned 703 rigid insulation, or Rockwool, or even acoustic cotton easy touch stuff, it's all good. The best source for most such insulation, especially Owens Corning 703, is SPI, they're distributed all over the country.


Bass trapping is essential, so few HTs even employ it ... there's a lot of what's called bass trapping ... but few actually are. It's hugely impactful, very reasonably priced when DIY'ed.


Good luck

Do you mean something like this but of course against the wall.




I dont think I can get away with that but what about something like this? I can probably get permission from the boss for this. Yes, shes the boss. When mama ain't happy...
 
#13 ·

Quote:
Originally Posted by jholzbauer  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503298


I made some with Safe n Sound insulation from Lowe's. The material tested quite well against OC 703 back when I read up on it. Some stores only carry the 16" wide sheets, but you can order the 24" and have them delivered to the Lowe's store. I covered them with some cheap black felt called Jet Set from Jo-Ann Fabric's. The panels made a huge difference in flattening my response and a problem I was having with Audyssey setting my crossover really high.

Any chance you have pictures? I have both of those stores in town.
 
#15 ·

Quote:
Originally Posted by cessna1466u  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503316


Do you mean something like this but of course against the wall.

No, I mean filling up the space will insulation, then aesthetically trimming it out.

Quote:
Originally Posted by cessna1466u  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503316


I dont think I can get away with that but what about something like this? I can probably get permission from the boss for this. Yes, shes the boss. When mama ain't happy...

I understand, but no, what you posted will do a little, but nothing in the octaves where you need it the most.


If you take the same panel, and span the corner, instead on wall mounting, it'd be much more effective. There needs to be as big of a gap as possible, between the treatment material, and the boundary wall. Otherwise, it's ineffectual with regard to LF.


I think your situation is nearly ideal for filling all the area around the ent center with material, then face it with whatever fabric she'd appreciate.


I do understand the limitations ... I think it would be an aesthetic improvement myself, it would look very appealing, very unified, following the contour of the ent center.
 
#16 ·

Quote:
Originally Posted by jholzbauer  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24503341


I think the panels actually add to the appearance of my theater room.

+1
 
#17 ·
The other problem I have and you cannot see it in the picture but on top of the Martys is where the mains will be going. I am going to build 3 fusion 8MTM center channel type speakers and put them vertical one on top of each marty cube.
 
#18 ·
Here is one of the panels hanging close to a front speaker.

panelhanging.jpg 35k .jpg file


Here is the backside. It is simply a 2x4 panel with 1"x4" wood and a single brace in back to hold the insulation in place. The insulation is pretty rigid. I think just pulled the jet set fabric (acoustically transparent) around the frame stapled to the back. Added a couple of picture hangers and pads and it was done. I think ideally it would have a little more gap between it and the wall but this was most visually pleasing to me.

panelback.jpg 51k .jpg file


And here is the bass trap I built hiding behind my couch. You could fill in your entire corner this way if you wanted or you could just build a shelf above the subs and fill from there on up. I cut the insulation in triangles and stacked up, built a shelf on top and then built a wood frame and wrapped it in the same jet set fabric. This is in a dark theater so I wasn't too concerned with how it looked. You could dress up the wood frame and just fill in behind it with all the insulation.

basstrap.jpg 40k .jpg file
 

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#20 ·
Question for: FOH


Is that 3" thick "Safe-n-Sound" being used for absorbing panels for the mid to high frequencies? How does it compare to 4" OC703 for that purpose, and, would it be best to also go with a 4" air gap for this purpose similar to the OC703 panels?


The reason that I ask is because I need to add some more absorbing panels to my new theater room, and I can't afford any more OC703 at the moment, and being that my local Lowes has the 16" wide by 3" deep Safe-n-Sound instock for a much cheaper price, would it work as well as the OC703 for this purpose? Would it work even better if I were to go with two layers that would total 6" thick with a 4" to 6" air gap?


For my bass traps, I plan to use R-19 pink fluffy stuff in each corner cut into triangles and stacked from floor to ceiling, or would Safe-n-Sound work better?


For the new ceiling panels that I am going to construct, would it be ok to use the 16" wide & 3" deep Safe-n-Sound made into 32" wide by 5' long and 6" deep with a 4" or possibly 6" air gap? Or should I just save up and spring for the OC703?
 
#22 ·

Quote:
Originally Posted by Martycool007  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24506675


Question for: FOH


Is that 3" thick "Safe-n-Sound" being used for absorbing panels for the mid to high frequencies? How does it compare to 4" OC703 for that purpose, and, would it be best to also go with a 4" air gap for this purpose similar to the OC703 panels?


The reason that I ask is because I need to add some more absorbing panels to my new theater room, and I can't afford any more OC703 at the moment, and being that my local Lowes has the 16" wide by 3" deep Safe-n-Sound instock for a much cheaper price, would it work as well as the OC703 for this purpose? Would it work even better if I were to go with two layers that would total 6" thick with a 4" to 6" air gap?


For my bass traps, I plan to use R-19 pink fluffy stuff in each corner cut into triangles and stacked from floor to ceiling, or would Safe-n-Sound work better?


For the new ceiling panels that I am going to construct, would it be ok to use the 16" wide & 3" deep Safe-n-Sound made into 32" wide by 5' long and 6" deep with a 4" or possibly 6" air gap? Or should I just save up and spring for the OC703?

+1
 
#23 ·

Quote:
Originally Posted by Martycool007  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24506675


Question for: FOH


Is that 3" thick "Safe-n-Sound" being used for absorbing panels for the mid to high frequencies? How does it compare to 4" OC703 for that purpose, and, would it be best to also go with a 4" air gap for this purpose similar to the OC703 panels?

It's being used as a broadband absorber, and spacing it off the surface makes it even more broadband.


I like SafenSound Rockwool because it's cost effectiveness. We can split hairs and go into the minutia, but what's important is it's acoustically very similar to OC703, it's just slightly less handy to deal with,.. doesn't entirely hold it's shape like 703, but no problem.


Yes, the gap is important. Myself, I'd recommend double thickness of the 3" SafenSound, spaced off the boundary. That yields a more broadband absorber, which is the point. You do not merely want to filter the reflected energy.
Quote:
Originally Posted by Martycool007  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24506675


Would it work even better if I were to go with two layers that would total 6" thick with a 4" to 6" air gap?


For my bass traps, I plan to use R-19 pink fluffy stuff in each corner cut into triangles and stacked from floor to ceiling, or would Safe-n-Sound work better?


For the new ceiling panels that I am going to construct, would it be ok to use the 16" wide & 3" deep Safe-n-Sound made into 32" wide by 5' long and 6" deep with a 4" or possibly 6" air gap? Or should I just save up and spring for the OC703?

Yeah, the thicker the better, and a 4" gap or 6" gap is fantastic.


For ceiling clouds, I like the more rigid 703, just for user friendliness. But, the rockwool safensound is fine.


It's often recommended that employing 4" thick OC703, or 4" Rockwool, 4" air-gap is adequate for attenuation of specular reflections. Each room is somewhat different wrt the transition region, and loudspeakers typically lose directivity in the lower octaves, so if you need to address these reflections, the treatment needs to be thick enough to work.



As I mentioned above, by using treatment panels to absorb this reflected energy, it is important that they're effective (either via thickness, spacing, or both), so they don't simply attenuates the MF and HF. Thus making a more dull and lifeless reverberant field. Don't EQ the reflection, if it's a problem, either redirect it, diffuse/scatter it, or absorb it.



Bass trapping; Marty, either fluffy or SafenSound, it's all about GFR, gas flow resistivity, ... and this can be independent of density.

For the corner porous bass trapping, they need to be as thick as possible... as thick/big as you can sacrifice. Remember, with the thicker corner traps, a material with lower gas flow resistivity is what you want. Pink fluffy, or any fluffy, insulation that loose and uncompressed will be your best bet. It's both the cheapest and most effective.



Yes, any material stacked in there to the same dimensions will work, there are many examples of rigid 703 thickly stacked to the ceiling, ... and they'll work fine. It's just not the most optimal use of material. If I had that much rigid, I'd span each diagonal in the room, all 12 junctions. This is because covering more surface area works quite well. 4" rigid, spanning the corner, with a big air gap behind, is proven quite effective too. Surface area rules (if I had a finite amount of OC703 rigid, for trapping, I wouldn't stack it all up in the corner. I'd span as many corners as possible .. each four main vertical corners, the four ceiling/wall corners, etc.).






It just all depends what material you use, how much space you are will to give up to the treatment thickness.



If you want to use 4", use rigid 703 or equivalent product. If you want to use something from 6"-12", I'd say the Safe-N-Sound Rockwool, anything thicker fluffy is likely your best use of material and space. The fluffy does require being mindful of not over-compressing, and you can use some plastic bird netting, or similar .. to help it not to compress too much.



But again, you can use 8" thick of rigid if you want. Some use rigid, Superchunk style, stacking triangles of rigid in the corners .. floor to ceiling. As I said above, it works, it's just expensive.






Also, the more dense the material is, it looses it's ideal effectiveness. That's why it's so nice to see fluffy is both the cheapest and most effective at the super treatments. It's just a pain to deal with. It's been suggested a 34" face (corner) or larger, and fluffy is the way to go.



Now, if you find you're loosing too much MF/HF, and your room becomes a bit over-damped and lifeless, you can face any of your treatment panels and bring back that precious energy. Most simply use like a 6mil plastic ... common Visqueen. You could employ paper facing, and it will start to reflect somewhere around 1khz. A "pool liner" thickness of vinyl will return around 500hz and up. If needed, you can use 1/2lb mass loaded vinyl, it exhibits returns around 250hz and up.



To assure not to over dampen, ideally the ETC is the tool to determine placement. Some don't mind the over-damped environment.



Now the bad news, velocity based porous absorbers are actually the wrong tool for the job ... in small room and close to the boundaries. Velocity based absorption needs to be as close to the 1/4 wave point as possible, here's an image from Ethan Winer's whitepaper;





Unless you really can give up huge amounts of space, there are better methods, ie., pressure based absorption. Helmholtz resonators, tuned traps, pressure based absorption is really beyond the scope of this post. Suffice it to say, porous corner traps, as effective as they are, are relatively ineffective. I'd be glad to discuss pressure based approaches (if anyone's interested), but velocity based porous absorption is so much better suited for the DIY community.



Check this out just for comparison sake;



24" fluffy



12" fluffy



4"w/4" gap



2" on wall







Hope this helps
 
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#26 ·

Quote:
Originally Posted by JackNC  /t/1523172/diy-acoutic-panels-or-flower-prints#post_24510965


Geddes recommends a 2nd layer of sheetrock on walls and ceiling with green glue between it and the first layer. Has anyone tried that or know how well that works relative to bass traps?
A second layer of sheet rock would be used to reduce transmission through the walls and ceiling to adjacent rooms or the environment. Acoustic panels are used to reduce wave reflections inside the listening room.
 
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