AudioCircle
Audio/Video Gear and Systems => The Acoustics Circle => Topic started by: Rclark on 18 Apr 2013, 03:59 am
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http://www.amazon.com/Expanded-Polystyrene-Foam-Sheets-qty/dp/B0054R8Y20/ref=sr_1_2?ie=UTF8&qid=1366257345&sr=8-2&keywords=eps+foam
Maybe glue a couple back to back for 8" depth and use a QRD calculator and a saw?
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Wow, shipping is 2x the cost of the product! :o I hope you have a local source. It seems that maybe that wouldn't be dense enough to do a lot at lower frequencies but I would think it would work for diffusion of higher frequencies.
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Isn't that the stuff most diffusers are made from these days? I think it can handle as low as 3-500 hz if it's the same material.
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Isn't that the stuff most diffusers are made from these days? I think it can handle as low as 3-500 hz if it's the same material.
Try Lowes or Home Depot and you can even buy the materials to make the backing and trim to make them look pro.
You could also pick up a Ficus Tree or two which also work great.
Jim
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http://www.amazon.com/Expanded-Polystyrene-Foam-Sheets-qty/dp/B0054R8Y20/ref=sr_1_2?ie=UTF8&qid=1366257345&sr=8-2&keywords=eps+foam
Maybe glue a couple back to back for 8" depth and use a QRD calculator and a saw?
Why bother? Just buy the proven diffusors from GIK or Real Traps and be done.
Most importantly, remember you must measure if you want it correct. Placing them in the room and not measuring is not going to yield the best result. It's science and you should treat it that way. Sadly, most people here will tell you what to do but have never done it themselves (and don't believe in it) and will give you a lot of misinformation.
It's so easy it sad that most fight it. I heard a great quote by an attorney today. "If you can't fight the Science, you fight the man" -J.J.
And that's exactly what goes on here. :duh:
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Well I may have found a local source. No Jason I'm fully on board with you there. It's just I'm getting ready to buy a motorcycle next month though so Dual Core (measure-er) will have to wait. Any large audio purchases are on hold for a few months and least I can do this cheaply and just fiddle with them.
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Dont use glue, use foam in the can to glue them together.
As for the why bother part....well, you might enjoy it and even get some gratification
by building something with your own hands. For the $ involved you have very
little to loose.
Try a roofing or stucco supply house for your styro.
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They're gonna be pretty ugly, but I can at least get a feel. I'd like to build 7" depth, 3 of them at 2ft by 4 ft, for 8ft of coverage behind my Maggie's. I'm yonna see if I can't get this done on my next day off. It's gotta be local as shipping is ludicrous
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Home Depot's got 2" by 2ft by 4ft styro for $6.29 a sheet. I'm all over it.
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Home Depot's got 2" by 2ft by 4ft styro for $6.29 a sheet. I'm all over it.
Don't blame you. You might also think about sewing and craft stores, like Michaels (I believe they're nationwide) as they might come in different colors.
Nothing at all wrong with DIY room treatments. I suppose it is okay for DIY electronics, but not room tx...
Jim
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Don't blame you. You might also think about sewing and craft stores, like Michaels (I believe they're nationwide) as they might come in different colors.
Nothing at all wrong with DIY room treatments. I suppose it is okay for DIY electronics, but not room tx...
Jim
Yeah, it's pretty soft stuff, shouldn't be hard to make nice clean cuts, maybe paint em with something textured for some extra diffusion. They should be good for 300hz and up.
I'm just excited to kill that back wave. Should be able to do this pretty cheap, and make some simple stands for em, all that. At least to start.
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Also check into a hot wire foam cutter, Amazon has them pretty cheap. If weight isn't an issue, making the diffusers out of wood may be easier.
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Rclark:
It is more than just helping the 300hz and above, it will improve the soundstage by eliminating smear.
Let us know how it turns out. BTW, I did the same thing as I got some remnants from a recording studio (acoustic diamond shaped foam) that I used behind the Maggie's, this coupled with media storage on the front wall between the panels did wonders and made my room sound much larger.
Jim
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I believe it. I've read enough stuff on diffusers and Maggies, they seem to really like each other. No reason why I can't place these behind and push them around till I get something pleasing to the ear, then I can fine tune and measure later. I'm very very excited to take my Maggies further.
@JK, thanks, I'll probably just pick one up at Home Depot. Hoping to pick up the materials next Wed.
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The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.
BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV... :roll:
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The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.
BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV... :roll:
That works for me....
Jim
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The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.
BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV... :roll:
Nice.. thanks for the tip. My plan is to shove them as far back as possible against the back wall, as far from me as I can (and take away some toe in on my speakers and more straight on, to where that full back wave is hitting the diffusers). But, this is all new frontier type stuff.
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So is your plan to build one large panel or 2 separate ones.
You probably know about QRDude calculator, if not you do now..... :wink:
I work with styrofoam and used a hot wire table to cut mine, but
you would be better to cut it with a saw, a table saw would be best.
Youve prob seen this, but if not, heres a few shots of when I built mine.
There may be a tip or two in for you in there......HAVE FUN!! thats the main thing.
http://www.audiocircle.com/index.php?topic=96222.msg1035197#msg1035197
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So is your plan to build one large panel or 2 separate ones.
You probably know about QRDude calculator, if not you do now..... :wink:
I work with styrofoam and used a hot wire table to cut mine, but
you would be better to cut it with a saw, a table saw would be best.
Youve prob seen this, but if not, heres a few shots of when I built mine.
There may be a tip or two in for you in there......HAVE FUN!! thats the main thing.
http://www.audiocircle.com/index.php?topic=96222.msg1035197#msg1035197
Always thought your listening space looked awesome. Yeah, that's about what I have pictured as far as the diffuser. I think I want to build 3 seperate panels and mess with them, place them all together, space them out, try all sorts of configurations.
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The effective low frequency cut-off for the diffusor is as much about it's geometry as it is about the material it is made from. Typical QRD diffusors are really only effective to around 500hz for about 8" deep channels, so you're right to want several layers of foam glued up. Picts or it didn't happen....
Greg
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If I ever get the ambition....
http://www.youtube.com/watch?v=qFeM2uWuMZI
Jim
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From what I understand, the ideal diffuser type for Maggies is the QRD type that spreads horzontally, not both horizontal and vertical. To 500hz is fine, the eventual Dual Core and some bass traps will take care of below that. The Maggies don't load the room very hard, at least compared to anything else I've ever used, there's lots of bass, but the room doesn't bloat up like it always had before.
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From what I understand, the ideal diffuser type for Maggies is the QRD type that spreads horzontally, not both horizontal and vertical. To 500hz is fine, the eventual Dual Core and some bass traps will take care of below that. The Maggies don't load the room very hard, at least compared to anything else I've ever used, there's lots of bass, but the room doesn't bloat up like it always had before.
Not according to Josh358 who advised me to go with both horizontal and vertical diffusion.
Jim
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Always thought your listening space looked awesome. Yeah, that's about what I have pictured as far as the diffuser. I think I want to build 3 seperate panels and mess with them, place them all together, space them out, try all sorts of configurations.
Another thing you can try is placing an absorber/bass trap panel dead center on the front wall, between the diffusers which would be placed at the mirror points described above. Lots of folks on the MUG recommend this and of all the bass traps and absorbers I have placed so far in my room, the center absorber seemed to make a big improvement with my MMG's sound.
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Not according to Josh358 who advised me to go with both horizontal and vertical diffusion.
Jim
I'd try and keep the sound energy in the horizontal plane rather than sending it towards the ceiling and the floor. Psychoacoustically I feel that is better because it gives you more sound energy arriving from lateral angles which improves perceived soundstage spaciousness. The exception to this would be towards the rear sides and back of the room where vertical and horizontal scattering / diffusion can be useful especially with surround sound systems.
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I'd try and keep the sound energy in the horizontal plane rather than sending it towards the ceiling and the floor. Psychoacoustically I feel that is better because it gives you more sound energy arriving from lateral angles which improves perceived soundstage spaciousness.
Maybe for conventional box speakers, for planars which are Dipole, you need to breakup the standing back waves both sideways and up and down.
Jim
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Yeah I've never seen 2D diffusers recommended for Maggies before, that's a first. Every Maggie system I've come across in treated rooms has 1D diffusers in the back, and are recommended.
@Nyall, thanks for stopping in. I think I'll do the QRD type. I haven't checked into a calculator yet. Is there one you can recommend or are they all the same?
Also, if I cut a pattern for an 8' * 4' diffuser, but in three sections that can be seperated, is that bad? Or should I have three seperate smaller diffusers with their own complete QRD pattern? Does that question even make sense?
@JK, thanks for the tip, I'll look into that.
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That is a very cool and simple arrangement. In the past, I have experimented with acoustic tiles(2 per panel), and made a sort L shaped piece that could be hinged, allowing multiple angles. Placement was wherever it needed to be around the speakers with VERY good results when placed in the correct spot. Maybe I will try it again.
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Yeah I've never seen 2D diffusers recommended for Maggies before, that's a first. Every Maggie system I've come across in treated rooms has 1D diffusers in the back, and are recommended.
@Nyall, thanks for stopping in. I think I'll do the QRD type. I haven't checked into a calculator yet. Is there one you can recommend or are they all the same?
Also, if I cut a pattern for an 8' * 4' diffuser, and but in three sections that can be seperated, is that bad? Or should I have three seperate smaller diffusers with their own complete QRD pattern? Does that question even make sense?
@JK, thanks for the tip, I'll look into that.
Rclark:
Go to the planar porn thread, see post 10.... (http://www.audiocircle.com/image.php?id=32858)
There are many more with similar tx.
Jim
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Oh thanks Jim. That's an interesting setup, I'd love to see all the different measurements he or she took to arrive at that. Most of the setups I've seen have the 1D QRD type, and from what I can remember reading from those who've tried both, they preferred the 1D qrd type for Magnepans.
I think it had to do with the 2D type dispersing too much energy, or something like that. Usually what you find is a QRD type, and they are either dead center in a broad line, or they are smaller, and placed directly behind the panels.
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That is a very cool and simple arrangement. In the past, I have experimented with acoustic tiles(2 per panel), and made a sort L shaped piece that could be hinged, allowing multiple angles. Placement was wherever it needed to be around the speakers with VERY good results when placed in the correct spot. Maybe I will try it again.
What sort of accoustic tiles were you using?
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Try this one, it will do what you want.
http://www.subwoofer-builder.com/qrdude.htm
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thanks!
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Check out SLR Acoustic:
http://www.srlacoustics.com/diffusers/
The grid diffuser is $100.00 per 2' x 2' pair.
Chris
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Yeah, they are the company I'm most interested in for this stuff. That 8*4 foot diffuser for $600 shipped seems to be the best retail priced large diffuser going. Goal is to try and approximate that thing.
Probably going to be harder than I'm imagining it to be.
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Good choice. :thumb:
Allen is studio engineer and has tuned many of the studio's in and around Nashville.
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Good choice. :thumb:
Allen is studio engineer and has tuned many of the studio's in and around Nashville.
Rodge:
Do you by chance know Rick Vito, he's a killer guitarist and lives in Franklin....
Jim
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I don't think EPS will really be reflective for frequencies under about 500 Hz or so. 300 is too low an estimate I would think.
Even 6" deep wood diffusors won't work lower than 700 Hz - ish, though, so you should be okay with any regular size diffusor. I wouldn't go designing an 18" deep EPS diffusor.
If you do paint them, PAINT THEM WITH WATER BASED PAINT ONLY! Other paints will eat away the EPS.
Edit: And no, you don't need to use the mirror trick to place diffusors.
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I was only using 2'X3' ceiling tiles. Didn't expect much, but was very surprised at the outcome. I forget the cost, but they were relatively inexpensive.
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Rodge:
Do you by chance know Rick Vito, he's a killer guitarist and lives in Franklin....
Jim
No I don't know him. :dunno:
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I think Gik's are also eps, and when I asked about them was told they were useful to 300 hz. Has to do with the depths of the wells, not the material, right.
That big 4•8 also goes pretty low says the guy from SRS.
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I think with my crude understanding of things so far, I decided I'm not going to build a modular 4*8 that can seperate into three, I'm just going to build 2 seperate, 4' * 4' diffusers and put one each behind a speaker.
Nothing stopping me but the time to do it. So yeah, Wed is when I start on this.
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No I don't know him. :dunno:
He has worked with Bonnie Raitt, Fleetwood Mac, to name a few, as well as a solo artist and has done some studio work in Nashville....maybe not as much as Brent Mason or Johnny Hiland. He moved his family from Los Angeles after the big Earthquake in 1994....
Thanks for getting back on the question,
Jim
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I think Gik's are also eps, and when I asked about them was told they were useful to 300 hz. Has to do with the depths of the wells, not the material, right.
We have EPS diffusors and we have wood diffusors. However, none of them diffuse down to 300 Hz, and certainly not the GridFusors. The wooden Q7ds scatter down to 400 Hz or so I believe, but the GridFusors won't go much below about 800 Hz if memory serves me correct. The problem is most other companies list the scattering coefficients as the upper and lower limit of the diffusors instead of the actual useful diffusion coefficient. So in order to compete we list both, but we do at least distinguish that 350 Hz is not the actual lower diffusion coefficient. Diffusors would need to be well over one foot deep and you would need to be incredibly far from them to get real diffusion at 300 Hz.
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Well the gridfusors are very shallow and I don't think anyone would expect them to diffuse very low. but your QRD diffuser, the eps one, I inquired about that one and was told it would diffuse down to 3-500 hz.
Either way, no big. I would still consider successful diffusion to 700 hz quite an accomplishment. I'm going for 7" depth and so should be good and into 500hz at least.
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(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001870_zpsa2ff423f.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001870_zpsa2ff423f.jpg.html)
Well I ended up having the time to get these early. I can just spend Wed cutting. Anyway, it's a VERY large stack of foam, and these diffusers are going to be quite a bit larger than I was thinking.
Hopefully I've just turned my small room into an auditorium.
Well, time to download a calculator and read, plan this out. Definitely out of my element here. Wish me luck. :thumb:
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:thumb:
Rclark,
I used 4 2" layers (4'x8') and used DSA 20 adhesive between them (not going anywhere) and covered with wife pleasing Khaki fabric with a similar set up in all three of our homes!
Only took a wee bit of tweaking with the exception of the lake home. Ended up only applying to rear walls on the 1.6. May have been due to area rugs over quarry tile for wet feet!
Best,
Tom
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good luck,
keep the photos coming. I may go down the same route vary soon.
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Thanks. :thumb:
I have about 5 different pages/sites open, reading the finer points on this stuff. There's quite a lot to consider. The QRDude software looks to be very robust though. If I'm successful with it, then I'll make some smaller 2D types for my front wall.
Pretty excited. These QRD's are going to completely dominate the back wall. Which is what I was after I guess.
I suppose I should rename this thread.
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Wait. The QRDs are going on your back wall? The wall behind you? And then you might make 2D diffusers for the front wall (the wall behind the speakers)?
I must have missed your reasoning for this. I'll have to go back and look through the thread.
In any case, good luck. :thumb: Projects like this can be so rewarding.
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thanks :green:
think like these, only uglier:
(http://i44.photobucket.com/albums/f17/iostream1/diffusion_zps8acc4571.png) (http://s44.photobucket.com/user/iostream1/media/diffusion_zps8acc4571.png.html)
(http://i44.photobucket.com/albums/f17/iostream1/diffuser3_zps7c138599.jpg) (http://s44.photobucket.com/user/iostream1/media/diffuser3_zps7c138599.jpg.html)
(http://i44.photobucket.com/albums/f17/iostream1/diffuser2_zps9983eef3.jpg) (http://s44.photobucket.com/user/iostream1/media/diffuser2_zps9983eef3.jpg.html)
(http://i44.photobucket.com/albums/f17/iostream1/imagesCA10JN6Q_zps996731aa.jpg) (http://s44.photobucket.com/user/iostream1/media/imagesCA10JN6Q_zps996731aa.jpg.html)
I'll be looking at them, past my speakers, on the back wall.
Thinking small 2D diffusers for the wall I'm on, up above my listening position.
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Well nothing to it but to do it. Going to take me a few days, I only have 4 clamps.
First off comes the foil backing
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001871_zps50742171.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001871_zps50742171.jpg.html)
Oh look, the front label comes off too. Who knew.
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001872_zps082346a9.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001872_zps082346a9.jpg.html)
So using contact cement. The hot knife suggestion, well nobody has one I can just go pick up, not for less than $100. This adjustable, fine toothed saw seems to go through the foam like butter, and I can adjust the blade to make accurate cuts to depth. I guess some sandpaper will take it from there..
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001873_zpsfde6264e.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001873_zpsfde6264e.jpg.html)
First panel clamped up, CD placed to show the size. So far so good!
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001875_zpsa0b0ced6.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001875_zpsa0b0ced6.jpg.html)
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Either way, no big. I would still consider successful diffusion to 700 hz quite an accomplishment. I'm going for 7" depth and so should be good and into 500hz at least.
Yes, absolutely.
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I don't understand why they are being glued face to face in full sheets... please elaborate on what you are going to do to make this?
Thought would have been cut to length before glue-ing.
-Tony
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Because I'm just going to cut into the face of these, rather than slice them into pieces and glue them to something.
Lots of reading yet to do, and fiddling with QRdude, which looks like a very nice piece of software. Surprised it's free.
But I feel confident that I'll be able to cut finely and make some good higher freq diffusion too. I'll just go slow.
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Sorry. I still don't think I understand what you are going to do.
You are going to cut cavities into the what is now "block" of 4 layers of foam?
If so, with what? And why this way instead of something like PDR showed for his process?
Just curious.
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Sorry. I still don't think I understand what you are going to do.
You are going to cut cavities into the what is now "block" of 4 layers of foam?
If so, with what? And why this way instead of something like PDR showed for his process?
Just curious.
I'm pretty much shooting in the dark. This is all experimental.
PDR has a fabulous looking diffuser, and it's a one piece. What I was hoping to do was make this diffuser with very thin walls so I can have a lot of wells, and diffuse to a low range but also up higher, but also be modular so that it can be seperated.
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There's some info on diy foam diffusers here:
http://www.avsforum.com/t/1312919/diy-sound-diffusers (http://www.avsforum.com/t/1312919/diy-sound-diffusers)
Also this is a good source:
http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/ (http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/)
(http://i296.photobucket.com/albums/mm170/PDRCanada/QRD4.jpg)
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Well, let me ask, does anyone think my approach at construction is a mistake? I've only glued four panels and can always go buy 4 more. They're cheap.
What's wrong with cutting into a stack? I'm not seeing the problem. It will still be a 4*8 diffuser.
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Rclarck, have you decided what your going to use yet as far as well
width?
The picture above is the one I made, I chose 1 1/2" wide wells so
I used 1 1/2" sheets. You can see I have them all numbered on the ends.
If you are going to try and cut them out of a solid block, I would try it
before gluing any more together, especially if your going with narrow wells.
This stuff cuts very well on a table saw....but I'm curious to see what you have in mind.
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You think that would be better? cut strips and glue them to a backing? I might just take a step back and consider that. Gik has a QRD diffuser that is just a solid piece of EPS and so that was my inspiration. And I'd have four of them I can place together for one large pattern or pull them apart and have four 2*4 diffusers.
I can visualize the cuts, and if I take it nice and slow I think I can be very precise. Haven't decided on wall thickness yet, maybe half an inch?
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The issue that I foresee as a possibility is that, depending on the tool and technique you use, some of the cuts from the solid block might be kinda awkward to execute.
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Well the knife is very slim, it's basically a hacksaw blade. If I can go slow I think I'll be alright. I hope. No maybe you're right.
..reappraising.
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Seems to be it would be easier if you cut the separate parts first. What do I know? I haven't tried to build my own.
Are you doing the fins to separate the wells too?
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I think I am going to change course and just cut the pieces and glue them to boards. I'll go buy some new foam and maybe some 2*4 cardboard pieces for backing. I still want to be able to seperate it rather than have it be one permanently large, single diffuser.
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I think I am going to change course and just cut the pieces and glue them to boards. I'll go buy some new foam and maybe some 2*4 cardboard pieces for backing. I still want to be able to seperate it rather than have it be one permanently large, single diffuser.
Seems like a decent plan.
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You are going to have to be pretty crafty to do this modular approach.
On one hand you would need a large # sequence for a large diffusor. But if you break the sequence in half, from what I gather, performance suffers dramatically.
But if decided to make a large diffusor composed of a repeating sequence, I think this leads to lobing and performance suffers...
- Well, then I guess if above is true, it would mean you need should do a mix of sequences as smaller diffusors and put together into the large diffusor. This way you could later separate...
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I think I read that if you have multples, say 4 like I'm going to do, you would have 3 the same, and 1 with a different pattern.
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"This topic is covered in the chapter entitled The curse of periodicity in the book : Acoustic absorbers and diffusers: theory, design, and application By Trevor J. Cox, Peter D'Antonio, considered to be the bible when it comes to QRD diffusers. They advise that the excessive lobing can be offset by modulating the sequence via the introduction a second style of panel, positioned as per the Barker code.
Barker codes - based on info from Wikipedia
Where there is a +1 in the sequence, use your standard panel.
Where there is a -1 in the sequence, use a different panel, which has a different set of diffusion angles to the others"
http://www.subwoofer-builder.com/qrd.htm
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Ok, back into the fray, 4 oak hardboard panels
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001879_zps5ee7bf9c.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001879_zps5ee7bf9c.jpg.html)
And some extra tools to hopefully make this go nicer.
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001880_zps0c9b5d84.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001880_zps0c9b5d84.jpg.html)
I can just take the stack I've already glued together and just cut into it for fins too, so no waste.
A benefit of going this route is the diffusers will be a bit more photogenic, hopefully. Thanks for steering me right fellas.
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Temporarily detoured. Just put my foot through my laptop.
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Temporarily detoured. Just put my foot through my laptop.
:duh:
This is like one of those moments where you see something in your Facebook feed and you're not sure if you should "Like" it or not.
Sorry to hear that! Hope it was an inexpensive laptop!
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:green: VGA port still works and I just pulled down my 37 in LCD tv. All good. It was the screen I broke. It's an ASUS and I will buy another. Great stuff when you don't step on them.
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"They Don't Make Em Like They Use To"
:lol:
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:lol:
Well, using this big screen is definitely nicer, but it sucks to have to lug it around. Oh well, at least I can get this done now.
So one thing I've noticed, and was confusing the HELL out of me, was this thing about fin width and well width. I just thought they were the same thing.
But then you see on these wooden diffusers that they have very thin fins and wide wells. Styro diffusers are just fins. Or, rather it's almost like they are just wells.. no real "fins" on a styro one.
Anyway, I think I'm going to just set it to 1" fin, 1" well, 23 wells per diffuser and just go to town. Going to get busy slicing up all my pieces into 4" long, one inch strips and then glue them to the height need per well.
I have to do it this way since I bought 2" thick panels. I suppose I could have read all this first.
Anyway, it appears that with 1" fins and wells, I can get a scatters-at-250hz and works up to around 7000Khz diffuser. Seems pretty good. And I have a feeling this project will break me in and I can do some more treatment type stuff.
(2D's for my front wall)
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What are viscous losses?
I am torn between a 1" well, which the calculator says I get good performance across the board with about a 7Khz cutoff, and a .5" well, which gives more like a 13Khz cutoff, but says "viscous losses" likely.
Is that because you are trying to do too much at that point? Is it best to keep it in the 500-7khz range, and then use a different sort of diffuser for ranges above 7khz?
Or should I go for it and build one that does 500-13Khz and dare the "serious viscous losses", whatever those are?
Data for One Dimensional QRD (Quadratic Residue) Diffuser
Advanced N47+2,0 panel: Shifted down 2 depth units
Design frequency 500 hz
Number of wells: 47
Deepest well in inches: 12.71
Fin width in inches: .51
Width of wells in inches: .51
Ratios 2 3 6 11 18 27 38 4 19 36 8 29 5 30 10 39 23 9 44 34 26 20 16 14 14 16 20 26 34 44 9 23 39 10 30 5 29 8 36 19 4 38 27 18 11 6 3
Well depths in inches: .57 .86 1.73 3.17 5.2 7.8 10.98 1.15 5.49 10.4 2.31 8.38 1.44 8.66 2.88 11.27 6.64 2.6 12.71 9.82 7.51 5.77 4.62 4.04 4.04 4.62 5.77 7.51 9.82 12.71 2.6 6.64 11.27 2.88 8.66 1.44 8.38 2.31 10.4 5.49 1.15 10.98 7.8 5.2 3.17 1.73 .86
Block heights in inches: 12.13 11.84 10.98 9.53 7.51 4.91 1.73 11.56 7.22 2.31 10.4 4.33 11.27 4.04 9.82 1.44 6.06 10.11 0 2.89 5.2 6.93 8.09 8.67 8.67 8.09 6.93 5.2 2.89 0 10.11 6.06 1.44 9.82 4.04 11.27 4.33 10.4 2.31 7.22 11.56 1.73 4.91 7.51 9.53 10.98 11.84
Phase shift in degrees 15 22 45 84 137 206 291 30 145 275 61 222 38 229 76 298 176 68 337 260 199 153 122 107 107 122 153 199 260 337 68 176 298 76 229 38 222 61 275 145 30 291 206 137 84 45 22
Scatter 250 Hz Diffuse 500 Hz HF cutoff 13230 Hz
Period width 48.02 inches
Minimum distance to seating position 81.25 inches (3 times wavelength of lowest diffusion frequency)
Good result: Period width of 48.11 inches is not less than the design wavelength of 27.16 inches
Poor result: The well width less than the minimum .98inch to avoid viscous losses - Serious viscous losses may be encountered
Good result: Plate frequency of 23500 hz is higher than HF cutoff of 13230 hz, so it has no effect
Good result: The HF cutoff frequency of 13230 hz is 26.4 times the design frequency of 500 hz
True diffusion frequencies: 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 12500 13000 hz
Current strategy for recommending well width of .98 inches: Recommend well width so that wells are at least .51 inches wide to minimise viscous losses
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Slight update
Well I just decided the heck with it, I'll go ahead and build to 1". Now that I'm all tooled up, these won't be the last diffusers I build, etc.
But playing fast and loose is now costing me. Should have read QRdude first, now the 2" panels are too thick. So I have to cut all my panels into 1" strips, and stack them into my fin sizes.
I started this morning, making some marks, and using my new chalk line to mark off the lines to be cut
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001884_zps6e318759.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001884_zps6e318759.jpg.html)
my technique with the saw left a lot to be desired...
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001886_zps823d8f4a.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001886_zps823d8f4a.jpg.html)
So I pulled out my power sander to grind the few pieces I cut down to 1"
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001885_zps19a84bdf.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001885_zps19a84bdf.jpg.html)
So cutting with the hand saw is both slow and crappy, so needless to say, if I continued doing this to each piece of foam, I'd probably run out of fun points in a major hurry, so today I went out and upped my arsenal.
Nice Jigsaw.
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001888_zpsa0f07526.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001888_zpsa0f07526.jpg.html)
Now everything should go nice and speedy. The guided, powered blade will be far more accurate. Anyway, let this be a lesson to you all, use the calculator first before you buy your foam.
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No matter what the outcome......you have to respect a guy that just goes for it.
Its been my motto for years.....go Clark go!!..... 8)
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thanks! 8)
I'm still excited and hopeful for a very good outcome.
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Oh wow. The jigsaw is like magic. Project saved. I've just named this Skilsaw "Deus Ex Machina" for its as apt a name as could be.
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No offense, and kudos for taking the bull by the horns, but it just seems that with all the tools you have/had to buy, time involved, that it might have been better to go ahead and just buy the panels already made?
However, the feeling of accomplishment of building them yourself is priceless.
Jim
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Maybe, but when he's done he will still have the tools for the next job.
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I'm still doing alright. I haven't spent all that much at all. I just started backwards. We'll call these prototypes :lol:
And yes, I totally suggest buying retail if you can afford it. Gik, SRL, Realtraps, and more, have a lot on offer and can also provide all the advice you need.
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Maybe, but when he's done he will still have the tools for the next job.
True and I applaud him for taking it on.
Jim
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And you can never have too many tools.
This thread has also been great fun to read as it's gone on. The good advice, the rejection of said advice, the young folks proceeding as if a bull in a china shop, the looking around at the scattered remnants of best laid plans, the light bulb goes on.
“When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years.”
― Mark Twain
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And you can never have too many tools.
This thread has also been great fun to read as it's gone on. The good advice, the rejection of said advice, the young folks proceeding as if a bull in a china shop, the looking around at the scattered remnants of best laid plans, the light bulb goes on.
“When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years.”
― Mark Twain
I was always told, when you are young, you want to be old, when you are old you're just happy to be alive!
When I was 21, I was perfect, by 25 I was conceded!
Jim
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no idea what you wacko's are talking about... :) Just building some diffusers over here and couldn't be going smoother at this point
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001889_zps85617332.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001889_zps85617332.jpg.html)
The jigsaw also has a circle attachment I can buy. The Brahma 15's in my closet are starting to look useful again.
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(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001911_zpse59f35d2.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001911_zpse59f35d2.jpg.html)
Not much longer now, a few more days now till the raw QRD's without stands are done, and I have enough material left over to build 3 2'*2' 1500khz skyline diffusers for my front wall, or wherever, and will begin building them immediately after. This pic represents about 2/3 of it.
I'm at the point of choosing which finish I'd like, as I will be painting these.
Basstrapping will be next. At the minimum I can build some corner superchunks to start. Or I just might go Auralex. Imo Aurelex corner fitting basstraps and a DSPeaker Dual Core will probably be more than sufficient.
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3 of these
As you can see these are almost a foot deep.
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001907_zps602e670d.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001907_zps602e670d.jpg.html)
1 of these
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001906_zps25f8527e.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001906_zps25f8527e.jpg.html)
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Finished cutting today. Ready to begin sanding and then assembly, followed by paint and finish. The idea of an 8*4 diffuser sounds smaller than it actually looks when you have all the pieces cut. This will be quite a substantial device. I'll have to figure out some simple stands as well, probably just some low, broad bases. Because even at their raw height they match the height of my speakers, that is to say they're very tall and stands need only be a few inches in height, if that. I might get away with just a thick board.
Was only able to cut for a few hours at a time, and I did go back and buy some 1" panels at $3.58 a panel. Extremely cheap. Going forward with the 1" strips would have been agonizing. There are a lot of panels here. I also would have not been able to build this without a jigsaw, so I don't recommend going at it with hand tools. I'm not normally a diy'er, and in my mind, this being styrofoam, it seemed intuitive that it would be an easy job with hand tools. Even with the proper size panel to cut from, and power tools, this is slow work, and requires a mask and a lot of cleanup, and I'm still not done. Be ready to put your vacuum cleaner to work... have spare bags. A shop with a table saw is the only real way to get faster results, but I live in an apartment.
Anyway, I have enough material, as I said, for some 2D's, and will detail their build as well. I am anticipating a tremendous difference in my room.
Although I am enjoying this whole process, tremendously, for those with more money than spare time, I highly suggest buying retail. I now understand at this point that retail products in this category carry a lot of value for the money spent. Especially that SRL (I hope I'm getting that right) 8*4 for $600 shipped. That's a bit more than I'm spending here, but all you have to do is click a mouse button, and pow, diffuser. So. That's worth something for sure. All of the products I see now, the diffusers and other stuff from Realtraps and GiK as well, definitely appear to be worth the price.
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I highly suggest buying retail.
Why bother? Just buy the proven diffusors from GIK or Real Traps and be done.
http://www.audiocircle.com/index.php?topic=116052.msg1214625#msg1214625
:wink:
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I'll have a nice set of diffusers here, but given the time spent to build them the retail products look to be well worth the price.
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Just went to Home Depot to look at the various colors to choose from as I just finished sanding today. Sanding was a breeze with my big power sander. Just clamped all fin groups together and took all the ripples down.
Sanding went quickly, but the cleanup was even worse than from cutting as now I had this fine powder, just everywhere, up the walls, everywhere. Took an hour to clean and filled a bag just about.
Anyway, about to pop a bottle of zinfandel and start gluing. Should be able to listen tonight.
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(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001937_zps72293ab2.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001937_zps72293ab2.jpg.html)
Ok, so even the gluing process is excruciating. You can see my improvised method of books and clamps to keep everything steady.
(http://i44.photobucket.com/albums/f17/iostream1/Mobile%20Uploads/WP_001936_zpsf7755366.jpg) (http://s44.photobucket.com/user/iostream1/media/Mobile%20Uploads/WP_001936_zpsf7755366.jpg.html)
Ended up only having time to build 2 of them. I'll build the 3rd +1 and the inverse panel today.
So.. right now I have 1 behind each speaker. They completely match my speakers in size and are of course, wider. They're extremely large, but very very light and easy to move. I have them all the way back against the wall, aiming each speaker now head on with back waves going directly into the diffusers several feet behind them.
The effect is quite something! I'm listening to Duke Ellington, Live at Newport, and the effect is everything you've heard about diffusers. It's now obvious just how much the rear wave was reinforcing and also cancelling off the back wall. I no longer feel like I'm listening to both my speakers and the room, it's much more speaker now.
I can't think of anything that hasn't improved. Everything that was great before is now fantastic, imaging is far more accurate, drums have more presence, vocals crisper, I even played some muddy mp3's and am now able to discern a lot of the words being sung. Highs are extremely crisp... The soundstage is now incredibly dimensional, much more than before, just everything is better.
Will report more when the final "array" is done. So far yes, right choice. Treat your rooms!
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Good stuff, dude. Some of those pieces are pretty deep, that thing is much deeper than I thought it might be. :o
Pics in place?
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Impressive. A lot of time and effort definitely went into this. I applaud you, sir.
What are the final dimensions of each diffuser? Depth, width, height. Or is that in a previous post of yours?
How far back from the speakers do you have these? You mention several feet, but is that 3 feet? 4? 10?
Inquisitive mind wants to know.
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Nicely done, knew you would nail it..... :thumb:
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Thanks guys :thumb:
I'll go into more detail tomorrow and answer those questions. I came home tonight and all I wanted to do was listen to album after album. Couldn't pry myself from the system long enough to build the last two. It's so good that if I stopped now with just these two diffusers I'd be totally thrilled and want everyone to have a listen. The changes are absolutely profound. I was really understating my previous comments because I'd only had about an hour with them. Now I can hear just the crazy amounts of clear, easy resolution, huge soundstage, 3D, definitely very very holographic now. Also, they've removed distortions I didn't even know were there... Really has me flabbergasted by my speakers and amps.
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Looks great - are you able to place them closer to the back wall?
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Great job. Thanks for keeping us posted and glad you are happy with the results. More pics and info would be great.
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They are between 9 and 12 feet from me. I built the largest diffusers I could, basically. Have the day off and am meaning to go build soon but I simply cannot stop pulling down cd's. It's"wooooaaaah" all over again. That soundstage and detail is blowing my mind. Not to mention I suddenly have a very meaty midbass.. Lots of changes and a lot to take in. I'll snap some pics tonight too.
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thanks for the reply - I guess I meant how far from your front wall :duh:
I am wondering if I can get them closer to the wall with diffusion since I have a 14' length room and right now about 52" out from the front wall (in your terms) and sit out about 30" in my listening position - doesn't leave much room between my feet and the speakers.
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So what happened to all of those one inch strips I saw on a prior page? I can't recognize them in the pics of the finished project. Are they stacked up? They look like solid pieces in the pictures.
How much did you spend on the foam for the 2 or 3 you are making?
For those who follow a diy diffusor build for posterity...
I didn't want to throw it in the thread earlier, since you had bought quite a few tools by the time I noticed, but they do sell a specific tool for this called a foam cutter. It is a hot wire system. This would give you smooth cut ends. I think there would be no sanding step if this was used.
However, you would need some kind of jig to implement, and ensure straightness and consistency
http://www.amazon.com/Woodland-Scenics-Wire-Foam-Cutter/dp/B0006KSMEU/ref=cm_cr_pr_sims_t
there is bow guide option on this as well.
I planned to do a diffusor project this year and thought about foam, and found this. But have been leaning towards some other options.
-Tony
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I used a hot wire table....about 55" long and 30" wide...that we use at work when
I built my QRD. To be honest, I think I would just use a table saw next time, it would be
a chore to get straight cuts with a hand held device, I have a number of those as well.
RClark, its good to see that your happy with the results. I know it was a bigger task than
you first anticipated, but I bet you get satisfaction from knowing how well they work
and building them with your own hands. Or perhaps not..... :lol:
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Yeah, youre right, next ones will go twice as fast. :lol: 8). Now that I can build em, I can fine tune till cows come home and make different types as well.
And I will. The result has me utterly intrigued by room treatment. This has to be equal if not greater importance than your gear. As you well know, the results are pretty astounding. About to see how 4 of them work!
And now that I really can't hear my rear wall, my eyes are on the front..
Turns out these trap bass too, didn't know that... My Maggies are hitting hard on kickdrums, never would have thought it possible, Can't wait to see what full treatment does for that aspect.
The main thing I'm getting with the two is pinpoint imaging that is just all over my room now, and just incredible dimensionality. Used to be a certain cd that would bring it out but now everything is just like Imax 3D for the ears.
TraderXFAN, I'm ashamed to say most of those 1 inch strips went to recycling. I've saved 4 of the large 2" panels and they are about to become skyline's for my front wall.
Ok..more later. Back to "work" :thumb:
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And for the record, this is nowhere near the same as having some plants or a bookshelf in the way. We've all had plants and bookshelves in our room, this is a dramatically different, purposeful effect. I've never had a stack of random books do anything even remotely close to what these are doing.
If you want diffusion, you need diffusers. :D
Oh look! Videos!
http://www.youtube.com/watch?v=4nzmBhkR4JQ (those Realtraps diffusers look really really nice.)
and especially this one http://www.acousticsfirst.com/educational-videos-acoustic-sound-diffusion.htm :thumb:
Ok, almost time for a lunch break. Panel 3 is done.
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I'm jealous and impressed all at the same time. :lol:
What is the distance between the speakers and your diffusers (at least the ones directly behind the speakers)?
Looks like you built a 23 prime diffuser, correct? What is your well width? And what is the depth of your deepest well?
Thanks! I'm thinking of actually just buying some instead of building it. With a busted knee in rehab, dogs that need attention and a girlfriend that would prefer that I paid attention to her, I don't think I have much time or energy to be building stuff...
Nice work. :thumb:
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Thanks. :thumb:
Well width and fin width are both 1". Deepest well is 10.62 inches :o :lol:. About as deep as I can go in my room, according to the experts. The calculator says my listening position is good though, and all I hear is ear candy. I spent all morning listening for anything wierd and nope, all good.
Yes, buy them, the manufactured models are worth it, and on top of that your girlfriend will like them better than my diy model :lol:
realtraps.com
gikacoustics.com
primeacoustic.com
acousticfrontiers.com
..just off the top of my head. They are all ready to help you.
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What is the distance between the speakers and your diffusers (at least the ones directly behind the speakers)?
[/b] :thumb:
And don't worry, I'll get those measurements too. The best method is to calculate your room with a room measurement device. The only reason I'm going in feet first is it seems a pretty safe bet according to many other users that Magnepans + QRD's against the wall =awesome. Fine tuning will come later.
At this point I would say the speakers are about 3.5 to 4 feet away from the diffusers. It will all make sense soon.
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Ok, fine. You got me.
I'm jealous, impressed and impatient all at the same time. :lol:
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Well width and fin width are both 1".
RClark... if your diffusors are the ones pictured, you have no fins!
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Like I noted in a previous post, it's as though the styro models are just wells. Mine are this type of QRD:
(http://i44.photobucket.com/albums/f17/iostream1/foam_zps6137175e.jpg) (http://s44.photobucket.com/user/iostream1/media/foam_zps6137175e.jpg.html)
rather than this type:
(http://i44.photobucket.com/albums/f17/iostream1/wood_zpsd0257d3d.jpg) (http://s44.photobucket.com/user/iostream1/media/wood_zpsd0257d3d.jpg.html)
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Not criticizing, just trying to clarify, for others, they don't really match the info that was projected in the modeling screenshots for qrdude that you gave.
Glad they work for you. Congrats.
What thickness backer board did you use? I suspect that has helped your bass, assuming these are not mounted to the wall?
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I was curious about the backer board as well (.25"). But I don't see how backer board would be better than closet door or.. wall, which didn't have an effect on the bass like this before. Has to be the diffuser.
I can't see this on graph form yet, but it sounds like everything has been flattened out tremendously and this has to be what's improving my midass. Bass is stronger too, and it's that dipole, planar bass, fast fast fast. Found myself turning it down to not disturb my neighbors but found I was averaging under 60dB. Wow.
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60db is a mere whisper, less than normal conversation.
Jim
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Yeah I know I've mentioned how my system works well at low volumes before but now it's all even clearer. It sounds far louder than it is with these in place, especially the bass now, apparently, not measured.
Almost done. Been taking my time with these last two. The inverse panel is slightly more difficult with more very low walls meeting very tall ones.
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Oh boy am I tired. Stayed up late finishing these.
My room isn't quite ready for prime time and I need a better camera for that, but here's a shot of the full diffuser. As you can tell, it's monstrous.
(http://www.audiocircle.com/image.php?id=80649)
That's John Coltrane's "Giant Steps" for size reference, CD. Well, about to put on something relaxing and pass out.
Next up for these will be trimming the tops and sides, sanding, filling any cracks with some sort of hardening putty I guess, primer and paint. Once all that's done and I have a better camera I'll take a proper photo of my room.
They are 3.5 feet behind my speakers by the way, and nearly extend completely wall to wall.
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Great job! :thumb:
Next step, buy a measurement device. Seriously.
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Thanks Jason :green:
And roger that. Think I'll just buy a mic and a soundcard and do REW. Really interested in seeing this on paper. And for now, on to the skyline build.
I'll post more impressions of the full diffuser later, but nutshell: WOW! Go science!
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(http://www.audiocircle.com/image.php?id=80681)
Here's a better perspective of the raw, unfinished build, next to my right speaker. Am loathe to take room pics though until the room is finished and I have a better camera. This one simply does not capture the color and details in my speakers. and it's fuzzy.
Anyway, now you have a better idea of where things sit at the moment.
On listening, beyond what I've said before, the effect really is like being in a much larger (enormous) space. And whatever noise floor or distortions caused by the room itself have either been destroyed or greatly attenuated. I didn't think it was possible to lower the noise floor any further, but there's all sorts of "noise" it seems.
Harmonies are so beautiful now. Vocals are a real treat. Now I can REALLY hear all the studio effects, and really really hear the differences in recording quality.
The effect on resolution is just incredible. I'm extremely familiar with my gear at this point. But last night I was listening to a song that had an electronic beeping in it. All this time it was a beep. Now with the diffusers in place, I can hear that that tiny delicate sound was no beep at all, it was a word being spoken, compressed and whatnot, but an actual word. You think you've heard as far as you can into the mix, but now more is unearthed. All the delicate little parts in the music are now so clear and dimensional, laid out in space before you all as though from their own source.
They must be absorbing some bass too, something's going on, because my bass is out of this world, and very stout. I can't see it in graph form yet but it's obvious to the ears that everything's been flattened out tremendously.
I don't think I can ever go back to an untreated room, this is way too cool, way too large a sonic improvement. Only forward now, more.
Before upgrading speakers or equipment, you all should give aggressive room treatment a consideration. Forget cables and wires, do this first.
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That diffuser looks like a lot of work. :o
And those Magnestands sure do look beautiful! Enjoy! :thumb:
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Thank you very much!
They really are very pretty and deserve a better picture with better lighting. Looking forward to making some nice recordings of them in action as well. Anyway, about the diffuser, I'm looking forward to finishing and painting it. But I think I'll wait another week or so because an artist friend of mine is in the middle of painting for me a 40 inch by 30 inch Jimi Hendrix oil painting and the background is a bright orange color so I'll want to see which color might go with it best and not draw too much attention.
Hopefully today I can begin the skylines, which shouldn't be anywhere near as hard to build.
And next month I want to rent a truck and buy basstrap materials.
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Ok, so in marked contrast, skyline's are incredibly easy to build
(http://www.audiocircle.com/image.php?id=80859)
I just built this whole thing from nothing in a matter of hours. 2' by 2' with 4" deepest well. It'll get sanded and cracks filled, painted. Another one built tommorrow. I didn't sand first, just wanted it built. It'll look much prettier.
Was a small fraction of the effort needed for that big qrd, and voila, skylines.
edit. glue's still wet so I was able to tighten up the lines. Looks nice.
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I had a lot of fun building a 'proof of concept' skyline diffuser out of 1x1 pieces of wood, glued to a piece of plywood. Came out looking awesome, but too small to be effective, and heavy as shit! I didn't use any kind of calculator, just made 1,2,3, and 4 inch sections and randomized as best I could.
Concept proven? Only that wood is too heavy.
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I had a lot of fun building a 'proof of concept' skyline diffuser out of 1x1 pieces of wood, glued to a piece of plywood. Came out looking awesome, but too small to be effective, and heavy as shit! I didn't use any kind of calculator, just made 1,2,3, and 4 inch sections and randomized as best I could.
Concept proven? Only that wood is too heavy.
Think Balsa Wood!
Jim
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Think Balsa Wood!
Jim
I believe I did consider balsa wood... until I looked into the price. :o
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The above diffuser cost less than $10 :)
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Holy. . Mackerel.
This stuff is so fun. Just got home from poker night and hung the single skyline a couple feet above my bed. Now, tomorrow night I'll have three of these.
The giant QRD is, as I said, providing huge dividends on that back wave, but I've been doing little tests as I go along and one of them is I clap my hands upon entering the room.
Even with my QRD, upon entering the room many feet from those and clapping my hands revealed some ringing.
I just clapped my hands with this single skyline added opposite the QRD, near me, and the clap sounded like it was coming much more from my hands, less from the echo. There is still some ringing, we'll see how that improves tommorow with two more.
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Holy. . Mackerel.
This stuff is so fun. Just got home from poker night and hung the single skyline a couple feet above my bed. Now, tomorrow night I'll have three of these.
The giant QRD is, as I said, providing huge dividends on that back wave, but I've been doing little tests as I go along and one of them is I clap my hands upon entering the room.
Even with my QRD, upon entering the room many feet from those and clapping my hands revealed some ringing.
I just clapped my hands with this single skyline added opposite the QRD, near me, and the clap sounded like it was coming much more from my hands, less from the echo. There is still some ringing, we'll see how that improves tommorow with two more.
Hi Rclark and all Audio Circle members.
Your project is super interesting for me and I am sure for other Audio Circle members.
Styrofoam here in Vietnam is inexpensive. (Super cheap)
Did you make the small styrofoam parts from a big board, let say 4' X 8' ?
Please let us know where you have hang up the diffusers in your room.
Guy 13
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RC, can you compare the QRDs with the same size of Skyline panels behind your Maggies?
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Rclark, you're inspiring DIY acoustics mania... my sub builds are next, as well as my tube preamp kit, but this thread has me stoked to do a few diffusers, too.
Speaking of, I just found the old thread where we were talking about building a skyline. I did not make 1", 2" cuts etc. I guess I found some dimensions somewhere, because I wrote this (in case anyone's thinking of doing one):
For a 2'x2' panel, the 2"x2" pieces are:
38 pieces - 1 7/8"
38 pieces - 3 3/4"
40 pieces - 5 5/8"
15 pieces - 7 1/2"
(This includes space for 13 blanks - 0").
http://www.audiocircle.com/index.php?topic=97780.msg981336#msg981336
Now I'm inspired to build a couple of foam ones, since they're so cheap and easy (although I'm not sure how easy painting will be...). Checked RPG prices and a 2'x2' is like $365!
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RC, can you compare the QRDs with the same size of Skyline panels behind your Maggies?
Hahahah hmmm no :lol:. Now that would be a different story, and would take some time to build. But would certainly look really cool.
You know what, maybe in the future, after I'm set up to measure, I could build a giant skyline and compare it vs a QRD behind the Maggie.
@ Neekomax, yes, that's true, but the retail products are still worth it out of sheer convenience, and default build quality. I threw that first Skyline together to see how fast I could build it. When I go slower on these next two, and take finishing and painting into consideration, then you see that the RPG is a little steep, but probably worth it.
Can't say that for sure because I haven't bought one. For QRD's, definitely. The Realtraps diffuser is built with wood, and so is probably a bit more durable if you've got kids or if that's just a concern, although for me it isn't, and has fins which I assume let's it go higher.
Yeah, foam's great. Btw, I've been using Elmer's Wood Glue. Was told to use contact cement, but that stuff is brutal, and didn't want fumes. Wood glue dries strongly.
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Hi Rclark and all Audio Circle members.
Your project is super interesting for me and I am sure for other Audio Circle members.
Styrofoam here in Vietnam is inexpensive. (Super cheap)
Did you make the small styrofoam parts from a big board, let say 4' X 8' ?
Please let us know where you have hang up the diffusers in your room.
Guy 13
Hi Guy :D, yeah for the QRD I built from 1" deep, 4' by 2' panels. For the skylines I am cutting from 2" deep, 4' by 2' panels, the one's I'd mistakenly purchased initially.
I will take pictures eventually. The skyline is above me, a few feet away. I just threw it up there, completely unscientifically, but when I can measure I will fine tune this.
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Oh, and to answer your question Guy, I did nothing more than hammer a couple tiny nails into the backboard of the skyline diffuser, tied some fishing line to those, and nailed a picture hanger into the wall itself, and hung the diffuser from it's wire onto that. It's extremely lightweight so I just needed one.
(http://www.audiocircle.com/image.php?id=80897)
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Cool project - I'm looking forward to seeing the measurements.
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Thanks Steve, me too. I'm going to look at inexpensive options to get REW up and running. And I will of course make sure to measure with everything removed as well.
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Absolutely amazing. I cannot believe how good this sounds. I finished a second skyline last night, and moved the two I have above me, directly in the path of each speaker. So big QRD way against the wall behind them, and now two skylines up front. The improvement with the two skylines added is just so cool. I noticed the effect before I even hit play. Was opening a popsicle and the crackling of the paper was loud, and this sounds were focused at the source rather than hearing the reflections as much. Very neat. The system sounds even better than it did.
Going to now build the last two of those for an 8' by 2' skyline array above me.
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WOOOOOOOOWW. Walked into my room after hanging the last two and spoke testing testing, etc, and my voice sounds very focused and close, not echoey at all. Playing some music and it all just sounds so good! I've run out of descriptors. Just incredible.
What I've gained with the skylines is just incredible focus. There's no impression of sound coming from the walls of my room anymore. It's a 3D, full bodied, eargasm with giant soundstage, resolution is increased, everything wow wow wow.
A further reduction in room-caused distorions, just an utter lack of any fatigue. It's all so organic and smooth. Bass is definitely being trapped by these. HIghs and cymbals are so crisp and decay in an instant. The bass is the most pleasant surprise of all. Definitely no need for a sub.
Here is a quick shot of the newly hung array. I rotated the faces to keep it random.
(http://www.audiocircle.com/image.php?id=81015)
The pieces for the skyline weren't as precise as the QRD. Imperfections in the 2" panels caused this. So there are some little gaps you can see here and there.
Bought expanding foam to take care of all that, and smooth out the faces. Then paint.
For those with Magnepan systems I absolutely recommend large scale diffusion. It's a huge, huge upgrade.
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Nice progress. So, you have diffusion behind the speakers and behind your head/ listening position. Do you have any treatments on the side walls?
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No I don't, and there is still ringing when I clap my hands. My speakers are dipoles, and don't really care about the sidwalls so much, but there are still improvement to be had for sure.
But if I don't touch my saw for a while or look at styrofoam panels any time soon I'll be good. In June I plan on building corner superchunks, and I think that will be a very easy, quick project.
Might also build some traps to pehaps build a cloud. I've heard that removing the ceiling accoustically brings some of the biggest benefits.
I also want, perhaps desperately, a Dspeaker Dual Core 2.0, but it's out of the budget for the time being. That should bring some good dividends on the bass.
Meanwhile I'll try and get a cheap soundcard and microphone soon, just to make some measurements, although, at this point they should just confirm what I'm hearing.
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I'm also considering a second 8' by 2' skyline above the one I have now. Why not? Also now considering completely sealing off my closet there and doing a floor to ceiling QRD. But, oh man, no more cutting styrofoam, not for a while.
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I like your concepts. I studied your pictures however and echo the previous observations that they are not matching the symmetry of standard diffusers. You may have had the offset wheel in QRD in a non standard position. Another thing is I have have found it is best in 8 or 10 foot width to make the diffuser one sequence, that is raise the prime number and play with the channel widths to optimize the design. To really impact the bass, make the depth 11 inches or greater. The material at Home Depot is low density EPS. Probably 1 lb or less. I use high density material ie 3 lb which makes for a sturdier unit with more mass. These type qrd units can be lined up and stacked floor to ceiling for fantastic effect. I am involved right now in making a 10 ft wide 40 feet tall qrd for a church sanctuary front wall. Good luck with your project, I hope to hear from you in the future!
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Hey :D
I kept the wheel at zero. And according to the reading provided by the calculator, 3+ panels and 1 - panel is okay, but since I am keeping it as one large one, I probably should have just made one sequence. But if you go back a few pages, you'll see that I kept the wheel at zero offset.
I'm at about 11 inch depth, so as you say, that must be what is impacting the bass. You're right though, it's fairly low density stuff.
I was about to make a post and say how nice everything is sounding. It sounds like the music is taking place in this giant ball of plasma around the system now, rather than reflecting from the walls. So they are definitely working. Will measure soon! There is definitely improved decay, improved everything.
Love your stuff! Hope to see you have more of a presence here.
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I appreciate your comment! Your observations are in line with my experiences. Nothing I have tried has improved room performance like large diffusers. In the past I have been handed my head around here for suggesting that bass standing waves can be mitigated with large enough diffusers. Now some of those naysayers are are preaching the same thing! The weight of the truth has more mass than hot air.....
I would be interested to see the outcome of your measurements. Your efforts reveal a real love for music and high performance audio!
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so......
I basically finished this project over a month ago. Since that time occurred.. I never think about gear, never crave the forum for information..
I just listen to music. I've definitely reached a nice plateau in audio nirvana. Constantly gobsmacked.
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That's kind of the Holy Grail! :thumb: It's great when you have a room that lets the music "breathe" a bit. The gear can get out of the way!
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BTW, RClark, would you like me to sticky this thread? Lots of good info here! :thumb:
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Go for it, that's great :thumb:. It's time for me to get serious again and buy more gear, a measurement rig, and start on basstrapping.
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so......
I basically finished this project over a month ago. Since that time occurred.. I never think about gear, never crave the forum for information..
I just listen to music. I've definitely reached a nice plateau in audio nirvana. Constantly gobsmacked.
Any final pictures?
Did you keep your prototypes, or did you make new sets?
Did you ever use Fins+Wells, or just the Wells as seen in your prototype pictures?
Did you coat them with anything or paint them?
TIA
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I have some more information for you...... I have painted styrofoam diffusers with high quality latex AND enamel paint. The enamel was actually very expensive, was designed to paint wrought iron fences, and I had NO problems with the "eating away" of anything. I had to use two coats to get the look I wanted, so now I start with a coat of Kilz original primer, then a finish coat of either latex or enamel. So really your finish options are larger than you thought.
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Any final pictures?
Did you keep your prototypes, or did you make new sets?
Did you ever use Fins+Wells, or just the Wells as seen in your prototype pictures?
Did you coat them with anything or paint them?
TIA
Hey! I've moved, and sort of went into other interests for a bit. The diffusers had put my system at pretty much the level I'd been dreaming of when I started this hobby. Now I'm in a smaller space, and will soon be focusing on bass trapping and room correction as this room is a bit tight.
Decided I'm not going to paint these. My plan is to slowly replace the large diffusers with fully built retail units down the road, or build large units from wood with fins, etc. These will last in the meanwhile though.
They are a massive upgrade and definitely helped the Maggies a lot!
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Curious, why replace with the retail units after you already did all that work?
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Oh it wouldn't be for a long time. Just to have something furniture grade rather than diy. This build was mostly to affirm whether they made a difference or not, and to not spend too much.
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On the subject of DIY diffusers--
I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/ (http://arqen.com/acoustics/acoustic-diffusers/)
Tim has come up with some very easy to build, quite inexpensive wood diffuser designs, particularly his "LeanFuser"s. I made a variation on these, varied because I'm in an "imperial unit" (inches) country with different nominal lumber sizes and wanted to use low-cost furring type lumber pieces. I used the AFMG Reflex evaluation program (as Tim suggested) to hand-optimize a 14-board wide diffuser based on his 7-board wide LeanFuser. I got all the wood pieces cut at Home Depot (cut for free!) and for under $100 got all the wood and panels to make 2.5 sets of 40" high by 35"wide diffusers. These are "step diffusers" which don't use the vertical wells of a QRD type diffuser and are less lossy than those types as well. And MUCH easier to assemble. With all the wood pre-cut, a little time beforehand marking up the ply panels with a pencil and ruler, and an electric 1.25" brad gun, it took under an hour to assemble them. Very fast to do and they look pretty nice, considering. They'd look better if I polyurethane'd them, but that's for later.
These covered an otherwise open section of concrete wall at the first reflection points of the loudspeakers. I was expecting an improvement to sound, but not this degree. It really made a great difference to the sound of the room. Previously it had been over-damped. I had filled in the beams in the (too low) ceiling above with absorbent covered with burlap. With the diffusers added, the sound became both more lush and much more detailed.
Highly recommended, if you have the freedom to put up something like these in your room.
edit: attached is a (crummy) phone shot of the basement listening room-in-progress, with the first-try diffusers set up. I'll be doing some floor-to-ceiling ones for the back of the room later.
(http://www.audiocircle.com/image.php?id=112127)
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On the subject of DIY diffusers--
I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/ (http://arqen.com/acoustics/acoustic-diffusers/)
Tim has come up with some very easy to build, quite inexpensive wood diffuser designs, particularly his "LeanFuser"s. I made a variation on these, varied because I'm in an "imperial unit" (inches) country with different nominal lumber sizes and wanted to use low-cost furring type lumber pieces. I used the AFMG Reflex evaluation program (as Tim suggested) to hand-optimize a 14-board wide diffuser based on his 7-board wide LeanFuser. I got all the wood pieces cut at Home Depot (cut for free!) and for under $100 got all the wood and panels to make 2.5 sets of 40" high by 35"wide diffusers. These are "step diffusers" which don't use the vertical wells of a QRD type diffuser and are less lossy than those types as well. And MUCH easier to assemble. With all the wood pre-cut, a little time beforehand marking up the ply panels with a pencil and ruler, and an electric 1.25" brad gun, it took under an hour to assemble them. Very fast to do and they look pretty nice, considering. They'd look better if I polyurethane'd them, but that's for later.
These covered an otherwise open section of concrete wall at the first reflection points of the loudspeakers. I was expecting an improvement to sound, but not this degree. It really made a great difference to the sound of the room. Previously it had been over-damped. I had filled in the beams in the (too low) ceiling above with absorbent covered with burlap. With the diffusers added, the sound became both more lush and much more detailed.
Highly recommended, if you have the freedom to put up something like these in your room.
What a great website, thank you for posting it. These look much easier to build and my understanding is the harder materials such at wood make much better diffusers.
Greg
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I'm in the process of painting some Styrofoam diffursors, having to do it via hand brushes and wanted to pass on a tip.
I've never been a fan of those cheap foam brushes, but have found them to work great in getting between and paint on the vertical sides of the fins, where a polyester bristle brush would have difficulties.
I just load up both sides of the brush, and can brush vertically and horizontally to basically "rub" the paint on. Then I finish up with a regular thin brush to smooth things out, catch any runs, and wick up any excess paint. Really a time saver.
(http://imagizer.imageshack.us/v2/640x480q90/538/0rwOys.jpg)
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And the finished product. These are "semi-diy" as the diffusers came as 2 x 2 units from SRL (bought over a year ago). Still, it was quite a bit of work to join, machine plum to fit the boxes, seal the edges and centers and paint. One coat of latex primer and three coats of latex flat wall paint (same color as the walls and ceiling of room). Got it down to two hours per coat per panel. Mounted in 1 x 8 diy oak boxes, on modified Sound Anchor stands (for Maggie MMGs) and casters.
(http://imagizer.imageshack.us/v2/640x480q90/633/X5SNLw.jpg)
Here's a pic of the room, with the finished diffusers and diy absorbers:
http://www.audiocircle.com/index.php?topic=128954.20 (http://www.audiocircle.com/index.php?topic=128954.20)
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And the finished product. These are "semi-diy" as the diffusers came as 2 x 2 units from SRL (bought over a year ago). Still, it was quite a bit of work to join, machine plum to fit the boxes, seal the edges and centers and paint. One coat of latex primer and three coats of latex flat wall paint (same as walls and ceiling of room). Got it down to two hours per coat per panel. Mounted in 1 x 8 diy oak boxes, on modified Sound Anchor stands (for Maggie MMGs) and casters.
(http://imagizer.imageshack.us/v2/640x480q90/633/X5SNLw.jpg)
Here's a pic of the room, with the finished diffusers and diy absorbers:
http://www.audiocircle.com/index.php?topic=128954.20 (http://www.audiocircle.com/index.php?topic=128954.20)
Nice project, wondering what they do for the sound. I'm looking at options for room treatment and would like your opinion if you get a chance.
Thanks,
Greg
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They made a big difference when I was running dipoles in the room (small Magnepans) They really helped tame the backwave of the speakers from over powering the small room. Comb filtering and such.
With the KEFs, they still seem to add a bit of depth to the sound stage, and add the highs back to the room after all the absorption panels were installed.
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I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/ (http://arqen.com/acoustics/acoustic-diffusers/)
Thanks for the link, Bill.
Look forward to the photo(s) of the back-of-the-room diffusers after you put them together.
Jim
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They made a big difference when I was running dipoles in the room (small Magnepans) I was even using an inverted QRD (basically the packing "opposite" that came with the SRL diffusers) in the center front wall, which also helped. They really helped tame the backwave of the speakers from over powering the small room. Comb filtering and such.
With the KEFs, they still seem to add a bit of depth to the sound stage. The center mounted unit didn't add much, so using an absorber there now.
Thank you for your input, I just got a pair of GR Research Super V's finished which are dipoles. You're the second person that I have read that said diffusers make a big different with dipoles. At what location(s) are you using them, the front wall or side walls?
Greg
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That's one heckuva speaker you just built. One thing I might mention is that when Danny was showing the SuperV's at the RMAF, he always used lots of diffusion, and those rooms always sounded great.
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Thank you for your input, I just got a pair of GR Research Super V's finished which are dipoles. You're the second person that I have read that said diffusers make a big different with dipoles. At what location(s) are you using them, the front wall or side walls?
Greg
Try them on the front wall, also at the first reflection points of the side walls. With my Maggies, I felt polycylindrical diffuser sounded best at the first reflect points on the side walls of my small room. But QRDs may be better there in your room. Polys are real easy to diy, unlike QRDs.
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Hey guys, I have built a lot of diffusers and tested them all with music. I recently had a customer from Texas that wanted a duplicate of one I sold him about a year ago. Amazingly I could not find his design but found another that was close in size that I had never made. In the process of covering it with Guilford of Maine cloth I was struck by it's performance. It absolutely sparkled and caused constant grinning as I readied it for shipment. I would like to point out that this design was created using Schroeder's equations in Excel and executed in high density EPS (unavailable from Amazon, Lowes, Home Depot etc.) And yes, it also enhances the bass in a very positive fashion.......
(http://www.audiocircle.com/image.php?id=134237)
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Srlaudio - did you mean "available" rather than "unavailable", or is this stuff different from what Lowes sells? How do you cut it without getting static-clingy styro particles all over the place? (hot wire?)
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All of the EPS panels sold at Lowes, Home Depot etc. are low density that is 1 lb or less per cubic foot. I use high density (3 lb per cubic foot) All my panels are made in a massive EPS factory with computer controlled cutting machines accurate to .001" accuracy. My AutoCad drawings are used to drive the machinery. I spec the density used and since they are cut from a solid block when I ship the bare ones I ship the whole block (the "negative" or inverse of the panel is included) this offers the best protection during shipping. I have never seen the high density material sold commonly because the low density has better R value for insulation application due to the air bubbles trapped in the material. Since my material is 3 times denser, it is of course more solid which improves it's acoustical performance.
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All of the EPS panels sold at Lowes, Home Depot etc. are low density that is 1 lb or less per cubic foot. I use high density (3 lb per cubic foot) All my panels are made in a massive EPS factory with computer controlled cutting machines accurate to .001" accuracy. My AutoCad drawings are used to drive the machinery. I spec the density used and since they are cut from a solid block when I ship the bare ones I ship the whole block (the "negative" or inverse of the panel is included) this offers the best protection during shipping. I have never seen the high density material sold commonly because the low density has better R value for insulation application due to the air bubbles trapped in the material. Since my material is 3 times denser, it is of course more solid which improves it's acoustical performance.
So, the EPS you use is more dense than the pink board insulation that HD sells? From the picture the product looks like the stuff they make coolers out of. It must be much more dense than that thou? So do people use the negative panel you send them as well? It seems like it would also work at diffusing the sound.
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Thanks for the link, Bill.
Look forward to the photo(s) of the back-of-the-room diffusers after you put them together.
Jim
Hi Jim,
I just saw your post (haven't come here very often in the past year), sorry for the late update. I've done several similar wood diffusers since then, including floor standers and a rather unique focusing diffuser arrangement (sounds like a contradiction, but isn't -- that one is the subject of an article soon to appear in Linear Audio magazine next year).
Bill
(http://www.audiocircle.com/image.php?id=134265)
There is more about these at http://www.diyaudio.com/forums/everything-else/269366-making-easy-diy-depot-sound-diffuser-panels-step-step.html (http://www.diyaudio.com/forums/everything-else/269366-making-easy-diy-depot-sound-diffuser-panels-step-step.html)
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Nice work, Bill. And appreciate the detailed description and explanation in the link.
Jim
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That looks great, Bill! :thumb:
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Thanks!
And happy 2016, everyone.
For anyone near a big hardware/lumber store in USA, that diffuser is almost silly easy to make, nearly all the wood pieces can be bought cheap and already in their needed dimensions, and need only a nail gun (or even hammer and nails) to put together. Biggest issue is whether you or your Significant Other can tolerate something that large in the room.
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Thanks Bill! I was familiar with Tim Perry's work at Arqen Sonic. But these look amazingly simple and easy to construct. On my list... Happy New Year to you
gab
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Thanks!
And happy 2016, everyone.
For anyone near a big hardware/lumber store in USA, that diffuser is almost silly easy to make, nearly all the wood pieces can be bought cheap and already in their needed dimensions, and need only a nail gun (or even hammer and nails) to put together. Biggest issue is whether you or your Significant Other can tolerate something that large in the room.
it might have a better WAF if it is covered with cloth - ask her what color and texture she prefers...