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| Re: D.I.Y. Diffusers [message #93401 is a reply to message #93398 ] |
Tue, 27 September 2005 11:12   |
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You can certainly make your own, but to work properly they must be built according to certain acoustic principles related to the laws of physics as they relate to sound waves (remember science? some here seem to be ignoring it).
Surely someone here knows of a good book whioch relates such things.
Egg cartons won't do it.
http://www.acousticsfirst.com/articles/diskmakers/index.htm
Attachment: egg.pdf
(Size: 186.88KB, Downloaded 294 time(s))
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| Re: D.I.Y. Diffusers [message #93462 is a reply to message #93398 ] |
Tue, 27 September 2005 15:04 |
 Dave @ D D
Messages: 508
Registered: May 2004
Location: Toronto |
Gold Member |
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If it's a small room then diffusors won't help as much as absorbers. What size of room is it ?
Dave T.
D&D Music
www.d-dmusic.com
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| Re: D.I.Y. Diffusers [message #93507 is a reply to message #93398 ] |
Tue, 27 September 2005 17:51 |
Bill Mueller
Messages: 2824
Registered: April 2004
Location: Joppatowne Maryland |
Platinum Member |
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Rich,
Very simple, very effective and very cheap diffusors are also some of the oldest designs, dating back fifty years or more. I have seen these for years in top recording studios and film houses. They do not look like what you would consider a diffusor however, but when used properly, they work very well at both diffusion and low frequency absorption. A good book to read is F. Alton Everest's book on Building a Recording Studio. Good stuff in there.
Ok, the structures I am talking about are called polycylinders. I have made these things for thirty years. The simplest way to make them is to mount verticle strips of 1"X3"X8' oak, 44" apart, to the wall with heavy duty wall anchors. I like to make a length wise cut in the strips creating a V between the strip and the wall to capture the panel. Then take a 1/8" X4'X8' Oak Luan panel (I like to finish them with Polyurethene) and wedge it between the verticle strips. It will bow out a few inches from the wall and create a nice poly surface. If you make the distance between the strips shorter, the bow will be deeper and it will be a bit harder to get them in, but I find it is better to slightly vary each one so they don't all resonate at the same frequency.
Because they resonate, they also act as a bass trap. You can calculate the exact F0 if you buy the book but I find them to be very effective bass traps no matter what spacing is between the strips. I further recommend that you staple raw fiberglass to the wall in between the strips. It will add absorption and effectiveness to the unit and of course will be invisible after the panels are up.
I usually mount them about 24" up the wall from the floor. This uses up less floor space, does not cover the AC outlets and gives you a convenient place to store your guitar amps. If you ceiling is not 10' then cut them down to 6' height.
If you have a large recording room, stagger them on either side of the parallel walls. You probably don't need them on both walls and they are very effective at breaking up standing waves. In a control room I put one dead center on the back wall with one or two on either side, depending of course on the width of the room. I also like to place them on the rear side walls to create a "live" end of the room. They are great for adding a live component to a Reflection Free Zone design.
They are very easy to take down when you move, and don't permanently damage the wall. They also look stunning and can give a very professional flavor to a room.
For the rest of the room, (front wall and side walls back a foot or two past the listening position) I recommend absorptive panels like Ethans RealTraps.
Hope this is helpful.
Best Regards,
Bill
"Don't take it personally. But this shit is a science." J.J.Blair
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| Re: D.I.Y. Diffusers [message #94266 is a reply to message #94038 ] |
Fri, 30 September 2005 12:45 |
BR audio
Messages: 9
Registered: September 2005 |
Member |
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Hey there,
I'm in the process of building some diffusors for a studio and I have to tell you that it is not as cheap as you think. Even if the R&D is done for you. I was doing the math on the QRDs from RPG and they would cost me in parts (wood, paint and stuff) about $350 to $400 each. That is not including labor. So I actually started to think that what they are chargin is not as horrendous as I originally thought. Even though they are producing them in greater quantities.
The problems with home made diffusors such as bamboos, plants, books in big book case and other objects, is the fact that you can't have any accuracy on what frequencies they are affecting. Not to say that it won't work, but it is just harder if not impossible to taylor them to your room's need.
I saw a repply that mentioned that you also need to consider your room size, and I agree. If your room is too small (bedroom size), you will be better of worring about absorption. The biggest problems with smaller rooms are in the low frequency range. Anywhere below 200hz. I would recomend taking care of room modes in that area before worrying about diffusion.
If you trying to stay in budget, don't even think about QRDs or Diffractals. Maybe the polys are your best choice..
my2cents
 Gil
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| Re: D.I.Y. Diffusers [message #94333 is a reply to message #93398 ] |
Fri, 30 September 2005 18:48 |
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Bill B
Messages: 139
Registered: July 2004 |
Active Member |
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| rdolmat wrote on Tue, 27 September 2005 11:59 |
Hi all!
Anyone have good tips or suggestions on DIY diffusers?
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I built some 'skyline' diffusors using the prime number theory posted on the BBC website. As you build more of these they fit togother to create a bigger diffuser, kind of a fractal thing. Here's a pic: (I hope)
BB
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