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Diffuser Wall Treatments That Aren't Ugly

watchnerd

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Anyone have any recommendations for diffuser wall treatments that aren't ugly?

I've seen a few that look like abstract sculptures, but not sure if they were custom or other.
 

Vincent Kars

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I have a couple on my website: http://www.thewelltemperedcomputer.com/HW/AcousticMaterials.htm

kvadrat_cloud.GIF
 

Jakob1863

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DonH56

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Note you can cover them with acoustic cloth at the cost of some HF signal loss. The cloth can be colored or printed with pictures, whatever. There are also thin membrane versions.
 

Fitzcaraldo215

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Just put some bookshelves, furniture, etc. They all scatter the waves and accomplish similar goals.
Yup. Ikea bookshelves with plenty of random books, LPs, CDs, other objects are both functional and practical. They do not need to cover an entire wall to be effective.

They can look surprisingly good and you don't notice the cheap flakeboard construction at all. I have never had their Billy shelves warp or distort in use.
 

Bjorn

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Just put some bookshelves, furniture, etc. They all scatter the waves and accomplish similar goals.
A diffuser distributes the sound evenly. Scattering doesn't.
http://www.lydogakustikk.no/?p=2137

That being said, a lot of so called diffusers in the market are simple scattering units. With RPG products, you'll see measurements of both diffusion and scattering.
 

amirm

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A diffuser distributes the sound evenly. Scattering doesn't.
http://www.lydogakustikk.no/?p=2137
I have heard the argument many times. What is lacking is controlled testing to show the audible preference.

Also keep in mind that those are theoretical arguments. In reality diffusers are not ideal devices and at any rate, are routinely misapplied. A broadband diffuser will be deeper than many people deploy and requires a healthy distance away from it for it to work like the textbook says. Those conditions are rarely met.

Here is the reality from Dr. Toole's book:
upload_2017-9-10_11-26-19.png


We see that the diffusion coefficient is frequency dependent.

In addition, speakers don't have same directivity at different frequencies. Here is a random example showing the same 4000 Hz per above:

https://tonefreqs.files.wordpress.com/2013/10/e-606-polar-pattern.jpg[/iimg]
What is delivered form the speaker is very different from forward to backward direction at that frequency. So if you put that diffuser on your front wall, it is not going to see an omni directional sound power as they do in lab testing.

And the angle hitting a diffuser may very well be different for each speaker (e.g. on a side wall). Or the secondary reflections.

Bottom advice is this:
1. If you are building a dedicated listening room that starts with an empty box, by all means use dedicated acoustic products.

Here is for example the side wall in our work theater while under construction (depth is about 12 inches)

Gallary Theater.jpg


2. For everyday listening spaces, products like above would be ugly and impractical. So opt for natural furnishings which accomplish the same thing.
 

Bjorn

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I'm well of aware that a diffuser doesn't exhibit a perfect polar. But it's still in another league compared to "books and furnitures". Obviously placement is important.

The picture you shows is an example of very poor treatment. Shallow diffusers, most with no proper diffusion and a combination of different types, thus leading to a completely chaotic response. And I agree, they look ugly too.
 

amirm

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I'm well of aware that a diffuser doesn't exhibit a perfect polar.
Not just polar but look at the alpha for each frequency. In addition they also have varying absorption. Nothing about them is "a diffuser distributes the sound evenly" as you said.
 

amirm

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The picture you shows is an example of very poor treatment. Shallow diffusers, most with no proper diffusion and a combination of different types, thus leading to a completely chaotic response. And I agree, they look ugly too.
The treatment there are for two parallel and independent multi-channel systems. Their speakers are mounted at different heights and hence the multiplicity of their types.

All of that was mounted behind fabric with a final look like this:

005K1644.JPG


With backlit LED to show what is behind them on demand:

005K1643.JPG


There are about $30,000 worth of acoustic products in there including some custom absorbers we have built. It was designed by Keith Yates and using computer modeling for low frequency and sub distribution:

f635d4_ececa2f44c11459c8ae0e27a21f595b9~mv2.jpg


So no, there is nothing ugly or chaotic about its implementation.

And those shelves are 12 inches deep so don't go by the illusion of the pictures thinking the products are shallow. They are not.

On the other hand, vast majority of diffusers sold to people are too shallow. People go by their pretty looks not realizing that they are not broadband.
 

Jakob1863

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Watchnerd didn´t give details or did ask what to do, so i tend just to provide some (hopefully) usefull information according to the explicite question. :)
But beside that, althought the technical meaning nor the usage of "scatter" and "diffusion" aren´t ultimately accepted, there is a difference between both.

Scattering with its redirection of energy might already help, given that there is enough furniture along the walls to break up "enough" regularity and a bookshelf could even provide sort of diffusion if the rows of books are arranged the same way as the wells of a diffuser.

But again, distribution of energy (as a diffuser does, although not perfectly) is something different than redirection of energy (which is what scattering provides) and so, as usual, it depends on the specific goals and conditions.
 
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