Wooden Ceiling Diffuser

mep · Jan 10, 2013

All,
I am trying to find information on how to build ceiling diffusers and where on the ceiling they should be mounted in reference to the speakers. What type of wood should be used, how thick, what width, and what angle should the diffusers be run on are all questions I have. My room is approximately 15' W x 23' L x 9' H. My room is an "L" shape room with the "L" portion going off to the left of the listening positioning which adds another 4' to the width of the room at the listening end. I would like to know how big the diffuser should be and some construction methods and where on the ceiling it should be mounted in reference to the front wall and the side walls. I'm not coming up with much info on my web searches.

Any help would be much appreciated.

Mark

microstrip · Jan 10, 2013

I have been considering some ceiling treatment, but still did not take any decision. I find acceptable the aspect of the Rives type blades, and hate the ceiling QRDs. As my room is only 8' I can not afford more than 1/2' for the diffuser depth.

mep · Jan 10, 2013

I still don't know what the ratios should be. How wide? How long? How deep? How many diffusers, what angle and how closely spaced? These are the questions I would love to have answers to.

DonH50 · Jan 10, 2013

Check the DIY Forum at AVS. There are a number of different types using different ratios (QRD, PR, etc.), and the size and depth is related to how large an area you want to cover and how low in frequency you want to go. Everest's text also has info on diffusers, as do other texts. There is not a simple answer.

Ceiling diffusers are often placed at the reflection point between speaker and listener, typically about half-way between.

Denser wood works better but is harder to hang (and support); light woods such as Balsa are OK for mid- to HF-diffusers (I think). You can also make them from dense foam blocks etc.

Does Toole's book describe them, or Ethan's book? I have them but not handy. I know my old grad text describes them, but using advanced math (4D calculus, ugh).

Ethan Winer · Jan 11, 2013

DonH50 said:
Does Toole's book describe them, or Ethan's book?

My book doesn't include formulas for designing diffusers, but it does list this site that has more information about diffusers than most people would ever want:

Diffusor Calculator

Scroll down the page to find links to other pages with technical info.

--Ethan

Nightlord · Jan 11, 2013

microstrip said:
I have been considering some ceiling treatment, but still did not take any decision. I find acceptable the aspect of the Rives type blades, and hate the ceiling QRDs. As my room is only 8' I can not afford more than 1/2' for the diffuser depth.

Most of all you need to break up the reflection. I'm using interleaved wood panels from speakers towards listeners, that doesn't take more than an inch off you height.

NorthStar · Jan 11, 2013

-- Ethan, I'm happy to see you; I always think of you. :b

rbbert · Jan 11, 2013

ted b (here and several other forums) had a ceiling diffusor built for his room a year or two ago

jfrech · Jan 11, 2013

mep said:
All,
I am trying to find information on how to build ceiling diffusers and where on the ceiling they should be mounted in reference to the speakers. What type of wood should be used, how thick, what width, and what angle should the diffusers be run on are all questions I have. My room is approximately 15' W x 23' L x 9' H. My room is an "L" shape room with the "L" portion going off to the left of the listening positioning which adds another 4' to the width of the room at the listening end. I would like to know how big the diffuser should be and some construction methods and where on the ceiling it should be mounted in reference to the front wall and the side walls. I'm not coming up with much info on my web searches.

Any help would be much appreciated.

Mark

Something like this? http://cgim.audiogon.com/i/vs/s/f/1356034357.jpg

Mine is just pine, with some trim around stained to match room and owens corning fibre board on the back side (you can't see that in this pick. Rives Audio worked out the dimensions for me...to me it is exponentially worth their fee (which costs about what good power cord cost or)

mep · Jan 11, 2013

jfrech said:
Something like this? http://cgim.audiogon.com/i/vs/s/f/1356034357.jpg

Mine is just pine, with some trim around stained to match room and owens corning fibre board on the back side (you can't see that in this pick. Rives Audio worked out the dimensions for me...to me it is exponentially worth their fee (which costs about what good power cord cost or)

Now we are talking! I like that design.

NorthStar · Jan 11, 2013

jfrech said:
Something like this? http://cgim.audiogon.com/i/vs/s/f/1356034357.jpg

---- Sumptuously/acoustically sound indeed.

mep · Jan 16, 2013

I'm starting to move further down the design path and I think the dimensions are going to be 10' wide by 12' long. It will look something like the design that MikeL has in where you look at it from the bottom you will have four separate compartments with the diffusers in them. There will be a 12" wide border of wood around the outside edges and the center line that will define the four compartments. I'm looking for suggestions for what type of lights and how many I should build into the bottom of the diffuser. I don't want it to be too bright in my room. I thought about using these:

http://www.lotusledlights.com/led-r...content=text&utm_campaign=RecessedLEDLighting

microstrip · Jan 16, 2013

jfrech said:
Something like this? http://cgim.audiogon.com/i/vs/s/f/1356034357.jpg

Mine is just pine, with some trim around stained to match room and owens corning fibre board on the back side (you can't see that in this pick. Rives Audio worked out the dimensions for me...to me it is exponentially worth their fee (which costs about what good power cord cost or)

Jeff,
I have seen that Mike Lavigne ceiling, that is also based on a Rives Audio design, uses the same type of slabs, but oriented towards the listener, not to the sides. Do you know why Rives choose not to follow his usual trend in your room?

mep · Jan 16, 2013

I thought the diffusers were supposed to be oriented towards the speakers and not the listener.

microstrip · Jan 16, 2013

mep said:
I thought the diffusers were supposed to be oriented towards the speakers and not the listener.

I have seen them used both ways!

mep · Jan 16, 2013

microstrip said:
I have seen them used both ways!

Maybe it doesn't really matter.

NorthStar · Jan 16, 2013

-- Mike, and Rives would know fo sur.

Mike Lavigne · Jan 16, 2013

mep said:
I thought the diffusers were supposed to be oriented towards the speakers and not the listener.

The bottom leading edge is aimed at the speakers. The idea is that the first reflection is deflected upward into some sort of absorption above. The room energy is then reflected back down into the room minus the first reflection.

mep · Jan 16, 2013

Mike Lavigne said:
The bottom leading edge is aimed at the speakers. The idea is that the first reflection is deflected upward into some sort of absorption above. The room energy is then reflected back down into the room minus the first reelection.

That is the way I plan on having them installed-facing the speakers. It makes sense to me.

Mike Lavigne · Jan 16, 2013

to the right is the speaker position.

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