DIY Front Wall Diffuser Panel

[kratu]

I'm considering custom-making a diffuser panel that will go on the back of the speakers. I'm seeking information and advice so that I can avoid mistakes.

I see several types of these panels. Most of them are wooden blocks of various sizes and shapes.

While, some are more artistic.

Mono & Stereo © 2023: RDACOUSTIC ACOUSTIC PANELS

There are others which are essentially long bands/strips that cover the walls; ceiling to floor.

Which ones are the most effective? How does one go about choosing these?
With wooden blocks, is there a recommend size? (2" or 4"). I prefer smaller ones.
Are there specific wood types that work the best (rubber wood, neem, mango or pine)

DIY Video of standard blocks

3D?

 

[srinisundar]

Easiest and working diffusers at my place behind the speakers in wall. I have placed 8 no's of same.

Regards

 

[kratu]

Youtube showed up this video

The summary is that, it made no major difference. Probably, I should carefully consider the size & proportions. Or consider other types of diffusers.

 

[Yelamanchili manohar]

Youtube showed up this video

The summary is that, it made no major difference. Probably, I should carefully consider the size & proportions. Or consider other types of diffusers.

1. Diffusion needs a large area to work from. A 4x2 feet panel is a minimum starting point. The more the better.
2. The room has to be treated with absorption to a certain extent, before merits of diffusion can be heard. Adding 4 diffusers in a room, with no other treatment, will bear zero results.
2. Placement is key, the distance from ear to diffuser has to be minimum of 10 feet. I've heard diffusers placed at 6 feet, and they mess up the imaging big time. No diffusion is better than closely placed diffusion.
3. The depth and design of the diffuser, dictates the frequencies it works on. Minimum depth of 7 inches is required to start working from 1250hz upwards. Depth of 13 inches starts working from 700 hz.
4. Sound whose wave length is more than the width of the baffle, wraps around the speaker and reaches the wall behind the speaker. The diffuser on the wall has to be effective at this frequency, or its a waste of money. For narrow baffled speakers like most bookshelves, say one foot wide for example, sound below 1113 hz will hit the wall behind the speakers. Adding a 7 inch deep diffuser which only works above 1250 hz here will be absolutely pointless. Infact absorption works better here.
5. Quadratic diffusers are 2 dimensional, so they play on sound width and imaging. Skyline diffusers are 3 dimensional, so they also contribute to height and depth of the sound stage.
6. Both diffusion and absorption reduce RTA60 tines. So it is impossible to measure with REW or anything else to determine which works better. Only way is to temporarily place what you plan and then listen if you prefer diffuser or absorber in that position.

Above are a few things to bear in mind when planning on adding diffusion. All the best

 

[mail2sumanth]

I get confused with Absorbers and diffusers, and it is the same case with most of the people. Generally we get confused with where to place what. this topic was discussed in some threads by fellow FM's. it is easy to get carried away with the information but rewind back and stick to min basic requirements. Fun truth of acoustics is you will not know that you badly need to treat your room until you do it and find the difference.
I recently ran a calibration in one of the room with zero acoustics except carpet and sofa, changed the basic manual EQ in AVR. This itself improved the overall sound in that room. If we add some absorbers in 1st and 2nd reflection points and to the back wall may improve little more. But you never know how it sounds until it is done and re-calibrated. there is a little struggle in getting the bass well managed though

-Ram.

 

[tonedeaf79]

This should help

 

[Anurag]

I'm considering custom-making a diffuser panel that will go on the back of the speakers. I'm seeking information and advice so that I can avoid mistakes.

I see several types of these panels. Most of them are wooden blocks of various sizes and shapes.

While, some are more artistic.

Mono & Stereo © 2023: RDACOUSTIC ACOUSTIC PANELS

There are others which are essentially long bands/strips that cover the walls; ceiling to floor.

Which ones are the most effective? How does one go about choosing these?
With wooden blocks, is there a recommend size? (2" or 4"). I prefer smaller ones.
Are there specific wood types that work the best (rubber wood, neem, mango or pine)

DIY Video of standard blocks

3D?

Did you finish the project?

 

[Hari Iyer]

Follow the 1/3rd rule for room treatments. 1/3 should be absorbed - your curtains, soft sofa furnishing, cushions can do this if planned well, 1/3rd should be reflective - your walls, floor, ceilings and some furniture can do a decent reflection in your room, 1/3rd should be diffused. Getting this diffusion correct is the key to get a balanced sound in your room. Some artefacts at your home if arranged in a particular way can also aid diffusion - like soft toys, home plants, some dome lights etc and need not be always a DIY diffusion panel which have a poor WAF. You need to have roving eye to look at your room and search for objects already in your home to achieve this diffusion. Always first and second reflection points are a good starting points to diffuse sound rather than absorb them.

 

[kratu]

Did you finish the project?

Follow the 1/3rd rule for room treatments. 1/3 should be absorbed - your curtains, soft sofa furnishing, cushions can do this if planned well, 1/3rd should be reflective - your walls, floor, ceilings and some furniture can do a decent reflection in your room, 1/3rd should be diffused. Getting this diffusion correct is the key to get a balanced sound in your room. Some artefacts at your home if arranged in a particular way can also aid diffusion - like soft toys, home plants, some dome lights etc and need not be always a DIY diffusion panel which have a poor WAF. You need to have roving eye to look at your room and search for objects already in your home to achieve this diffusion. Always first and second reflection points are a good starting points to diffuse sound rather than absorb them.

@Anurag I've not attempted to make this particular diffusion panel. As indicated in one of the videos above, It requires large blocks of wood in specific sizes; around 4x4 inches. Else, it wouldn't be effective. And as @Hari Iyer mentioned, those large blocks aren't appealing. Instead, I might try other diffusers such as panels with vertical stacks of wood in varying proportions.

I'm using the usual furnishing such as large sofa, thick rug, a spare bed, foam panels and glasswoov-based absorbers on first-reflection points. The biggest issue is the corners where low-frequencies stagnate. This becomes a problem as I increase the volume. The room of 12x12' is small. I've used rolls of corrugated packaging paper as bass traps.

 

[amrutmhatre90]

Check this video out, some good technics.

 

[kratu]

Check this video out, some good technics.

Thanks for the reference.

I think for a better diagnosis, I need to have a technical assessment first. I've purchased the calibration mic mentioned in the video. I hope this also helps in making incremental improvements as I see in the video.

 

[amrutmhatre90]

Thanks for the reference.

I think for a better diagnosis, I need to have a technical assessment first. I've purchased the calibration mic mentioned in the video. I hope this also helps in making incremental improvements as I see in the video.

Yes, a control should be always used as a baseline and start measuring things from there on.

Good to have a mic to make even minor adjustments to the AVR and trust me it works.

 

[Anurag]

i haven't yet gone through all the links and videos given above, but from my experience of trying these generic small diffusers, only a set of 8 makes a difference that trying better stuff seems worth looking into

https://www.amazon.in/gp/product/B07WW79C84/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Analogous]

This could be a game changer if the tech matures…

Scientists create paper-thin speakers that could be used like wallpaper​

It could turn your walls into noise-canceling surfaces​

Scientists create paper-thin speakers that could be used like wallpaper

MIT researchers developed flexible, paper-thin speakers that are easy to manufacture and can turn entire surfaces into sound sources.

thenextweb.com

 

[0verkilled]

I have been contemplating on making the Skyline diffusor myself. And have done all kinds of research - like youtube videos, blogs etc

The best material you can use, which is also cost effective is pinewood. This is the lightweight and most effective for this kind of project.
With in this, you can buy
Brand new unused wood - sold in cubic feet
Used wood - sold per kg - they will help you remove the edges by running through their machine a couple of times and will be as good as new

And no matter what you use, you can ask the people selling wood to cut it according to your requirements - all 3 dimensions.
There is an online calculator that will give you exact dimensions based on the frequencies you like to address - http://www.mh-audio.nl/Acoustics/DiffusorCalculator.asp

PS. I am still doing research, have not done any of it. However, I have worked with that wood and made a couple of chairs (with arm rests for my kids) and few other items, its the easiest wood to work with for beginners.

 

[Amarendra]

I have been contemplating on making the Skyline diffusor myself. And have done all kinds of research - like youtube videos, blogs etc

The best material you can use, which is also cost effective is pinewood. This is the lightweight and most effective for this kind of project.
With in this, you can buy
Brand new unused wood - sold in cubic feet
Used wood - sold per kg - they will help you remove the edges by running through their machine a couple of times and will be as good as new

And no matter what you use, you can ask the people selling wood to cut it according to your requirements - all 3 dimensions.
There is an online calculator that will give you exact dimensions based on the frequencies you like to address - http://www.mh-audio.nl/Acoustics/DiffusorCalculator.asp

PS. I am still doing research, have not done any of it. However, I have worked with that wood and made a couple of chairs (with arm rests for my kids) and few other items, its the easiest wood to work with for beginners.

What about creating a book shelf on the front wall behind the speaker with books placed unevenly in depth ?

 

[0verkilled]

What about creating a book shelf on the front wall behind the speaker with books placed unevenly in depth ?

Yes lot of people actually do this, and it will work. Only thing is you will have to keep experimenting, until you find the right pattern. May be there is no end to this experimentation. I am sure this will have some positive effect. However, may be not for the people who want to go too deep with room measurement, graphs etc.

 

[Amarendra]

Yes lot of people actually do this, and it will work. Only thing is you will have to keep experimenting, until you find the right pattern. May be there is no end to this experimentation. I am sure this will have some positive effect. However, may be not for the people who want to go too deep with room measurement, graphs etc.

Yes this is a controversial topic. People like Paul from PS Audio talk of the benefits of simple things like bookshelves while some (Gik Acoustics) talk of bookshelves as just absorbers rather then diffusers.