QRD Fractal Diffuser - Home Theater Forum and Systems - HomeTheaterShack.com

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post #1 of 8 Old 11-12-16, 04:25 PM Thread Starter
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QRD Fractal Diffuser

Saw these on eBay and wondered how effective they would be as they look like they are made of styrofoam.

http://www.ebay.com/itm/Skyline-QRD-...4AAOSwOyJX5FMA

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post #2 of 8 Old 11-12-16, 09:50 PM
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Re: QRD Fractal Diffuser

Took a good look at these... yup. Polystyrene.

Since they're supposed to diffuse sound by reflecting it rather than absorb sound, I feel like the material used only needs to have a fairly smooth and rigid surface, and polystyrene fits that bill pretty nicely. What I would worry about is mounting them, as it often tends to crumble when lower density material is used (as these appear to be). Also, they don't look like they're coated in any way... that could have pretty serious consequences cosmetically. Painting can be done, but you have to take care to avoid coatings that have any kind of base that will break the polystyrene down. Anything water-based should be fine, but aerosols could present problems.

The thing I'd be really concerned about is damage during shipping... but we'd finally get the answer to the age-old question: What do they back styrofoam in?
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post #3 of 8 Old 11-13-16, 10:30 AM
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Re: QRD Fractal Diffuser

If it's EPS, it can work down to the point where the material is not dense enough to deal with the frequency. If it's open stryrofoam, I'd stay away.

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post #4 of 8 Old 11-13-16, 05:24 PM
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Re: QRD Fractal Diffuser

Quote:
puukorva wrote: View Post
It's hard to say from the picture but the structure looks like it's not solid but expanded i.e styrofoam like. I'm actually thinking to order one piece just for kicks. If nothing else it can be used as a base for molding.
That's pretty much what I was thinking... at $40 and free shipping, it's a cheap experiment.
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post #5 of 8 Old 11-14-16, 01:44 PM
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Re: QRD Fractal Diffuser

That's a Leanfractal design.

Quote:
Tim Perry <[email protected]>
To
Quenten
Sep 23 at 9:03 AM

Hi Quenten
Everyone seems to love fractal diffusers, but to most of us they look ridiculously hard to build. I've tried to break it down for you with this modular fractal stepped diffuser.
I'd like to introduce you to my favorite diffuser design: the Leanfracal. You may have seen it featured on the Arqen.com homepage, or read about it in my diffuser design thesis (where it's known as A1-Frac).
Click "Display Images" to see me (señor Leanfractal).
The Leanfractal is my personal favorite because you can mount it using the same profiled modulations that are given for the Leanfuser. Mounted this way it can perform better than my other fractal diffuser design, the Stepfractal (B2-Frac).
The Leanfractal is also simpler to build! It's a straightforward extension to the Leanfuser. In fact, you can build an array of Leanfuser panels first, then upgrade them later to Leanfractal panels.
The very one I'm getting ready to build. I'll be using a combination of plywood & lumber. The guy that designed them offers his plans to everyone for free as long as you don't sell them commercialy. Those dispersion fields look exactly like the ones posted on his website. I'll link it over to him and ask his advice on how he thinks it will preform. He doesn't recommend altering the # of panels, he claims it has to built exactly that way to produce the desired effect.

Here's the link to his website. Some excellent reading.

http://arqen.com/?awt_l=4u1Q5&awt_m=...up&omhide=true
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Last edited by Tonto; 11-14-16 at 03:20 PM.
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post #6 of 8 Old 11-14-16, 11:00 PM Thread Starter
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Re: QRD Fractal Diffuser

I look forward to hearing what he has to say.
On a side note, I wonder if they have any flame retardant chemicals as styrofoam isn't good if it burns.

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post #7 of 8 Old 11-14-16, 11:31 PM
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Re: QRD Fractal Diffuser

Quote:
robbo266317 wrote: View Post
I look forward to hearing what he has to say.
On a side note, I wonder if they have any flame retardant chemicals as styrofoam isn't good if it burns.
At $40 with free shipping from Latvia, I wouldn't bet on anything fancy like UL Listings and such
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post #8 of 8 Old 11-15-16, 01:38 PM
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Re: QRD Fractal Diffuser

That's what I'm thinking. I post Tim's response when he responds.
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