# diffusors



## nineballg (Jan 19, 2008)

i am ready to by material for my diy 2"x2" block style diffusors.
i have already built a couple using wood and the final result was about 30lbs for a 18"x18".
i asked here before if packing styrofoam would work instead of wood, provided that i paint and seal them.

the response i got on here was yes they will work but not quite as good as wood for the lower frequencies.
i was at the hardware store yesterday and came across two different foams. 

the first foam is your standard white packing foam.
the second was a much denser harder foam. owens corning made the hard pink foam and dow made the hard blue foam.

obviously, i would like to use the hard foam but at a cost of 2.5 times as much as the standard white foam, i would like you save quite a few bucks since im planning on building a number of these panels.

does anyone know if the couple hundred bucks extra spent on the denser foam will privide that much of a difference over the standard foam. if it helps , the longest blocks on my panels will be about 7" long which would mean a few 7" deep wells.

thanks all


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## collo (Dec 23, 2006)

I don't know the answer directly, but may have a suggestion...

Xenon built some 1D diffusers using blue foam and faced the wells with thin ply.

I'm wondering if you could use the same trick on your 2D unit, using the cheaper white foam and face the well bottoms with squares of thin ply in the same fashion.

With a block style diffuser that has no fins, there is so much energy leakage around the blocks that the most important surface becomes the bottom of the wells. Just making that part rigid should be enough.


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## PepAX7 (Mar 11, 2008)

I'm not sure about the blue/pink foam as far as STC (sound transmission Coef's) value! The higher the number, the better blockage @ given freqs. If your lookin' to diffuse, this may not be appropriate, but... I've been looking into a company called "Roxul" especially their AFB and Cavity Rock brands. I don't think these are foam, but they may have something available on there website.

A builder friend of mine turned me on to this stuff and said it was very inexpensive compared to the Dow Corning products.

I'm working on some bass traps for a House of Worship and I'm planning on using the AFB 6-8" material. Haven't got local prices yet... still in designonder:

Check it out!

Pep


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## markbrightuk (Jun 16, 2010)

I made a set of 3 wall diffussers which not only work well but look great. Basically a wooden frame backed with hardboard which I packed quite loosely with cut to fit pieces of old nylon duvet (also the advantage of fire proofed) covered with speaker cover material. I used black material but it's also available in various colors so your studio doesn't have to look so obvious. They are 24" x 16" & 2" thick. I used 2" by 1/2" wooden batterns for the frame as I had it already. I've made some larger ones for a friend and used a darker shade of beige to match his walls. I also buy Auralex style foam which is £35.00 for 12 -12" x 12" panels either flat or egg carton style and now always mount on thin MDF board using spray adhesive. This enables them to be hung on the wall or from the ceiling instead of sticking direct to the walls. I've made my own bass traps for the corners packed with light rockwool again covered with speaker cover material. When you consider how expensive the main manufacturer of foam accoustic panels, making my own cost a fraction of what they cost.

I'm now making larger free standing panels for isolation with the shiny side of hardboard on the back so they double as reflection panels.

After much trial and error and reading I feel very confident in treating any recording rooms now. My tip is too make sure your room isn't very dead as some are. carpet on all walls isn't the best solution. Room accoustics is about trapping, diffussing and reflecting sound, not just have a dead room. Proof of this is when engineers place mics outside the live room down the corridor and leave the door open to help create a real sound and some natural reverb.

Years ago I thought engineers were full of mystical powers and i was scared to turn a switch on a mixer and just play my guitar. I now know that this is untrue and what engineers say to keep us musicians in the dark. They also spent hours experimenting with mic positions, mutiple mics and rooms to record to find their best way. I now know the best mics & positions to record guitar through an amp. Another tip if combo amp has ab open back is to place one mic at the rear of the amp along with one or two in front. Hope this helps any begginners and i welcome any feedback or ideas. cheers mark :T:bigsmile:


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## maikol (Nov 7, 2008)

collo said:


> I don't know the answer directly, but may have a suggestion...
> 
> Xenon built some 1D diffusers using blue foam and faced the wells with thin ply.
> 
> ...


Interesting idea to fill the wells with styrofoam and then just glue thin plywood on it, thanks for the link!


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## markbrightuk (Jun 16, 2010)

I've made them using foam I purchased as a mixed set of 36 12"x12" panels which I mounted to thin MDF & hardboard using spray adhesive and then framed using 22x1" wood I happen to have. The foam is grey so painted the frame a black / silk finish and then hang on the wall. The foam I purchased from a company who cut foam to order and had ready made accoustic foam panels. The 1st order cost £35 or $50 with any mutiple orders of the same only being £10.00. It's a UK company but there are many in the states as well. The foam is slightly softer than the same Auralex make but much cheaper. I've also painted some as they are easy to paint either with a brush and regular emulsion or spray paint. The diffussors I made were based on DIY studio panels I found on the net. I friend of mine is a proffesional engineer in a well known london recording studio and most of the accoustic treatment they have was made to order by a carpenter.


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