[Sonny]

I have been looking for an affordable or simply DIY solution for some diffusers and ran across this, any thoughts:

https://www.2modern.com/products/acoustic-weave-tiles-set-of-12

Made of recycled paper and seems like the designs would diffuse sound waves, but wasn't sure if the material had to be of a certain sturdiness...

[Bob2]

Those look like they may be very good but there are many, as I'm sure you know that are cost effective.

I built several of these, on a 2X2 foot oak ply base using cedar siding and feel they do a decent job of diffusion for a ridiculous low cost.

[Sonny]

Bob, those look great!  I don't have the tools to cut the siding in the angles like you.. so that would be an obstacle for me.

[rodge827]

Bob,

I bet they smell good to 

What are the dimensions of the triangles?

 Chris

[Rob Babcock]

I have been looking for an affordable or simply DIY solution for some diffusers and ran across this, any thoughts:

https://www.2modern.com/products/acoustic-weave-tiles-set-of-12

Made of recycled paper and seems like the designs would diffuse sound waves, but wasn't sure if the material had to be of a certain sturdiness...

The design is attractive but there's very little solid info on their site.  My suspicion is that they're too lightweight and too small to really offer great diffusion.  Maybe at very high frequencies but I suspect that most wavelengths will pass through them with very little effect.

[FullRangeMan]

Its cheaper than wood?

[JLM]

Simple physics versus wishful thinking:

1.)  To be effective diffusors must be made of acoustically opaque and reflective material (so you can dismiss thin plastic, cardboard, or paper) and of varying depths (to cover a range of frequencies, the deeper the lower frequency they will cover).  The product can't diffuse if the sound is absorbed or doesn't reflect across the entire frequency range in question.

2.)  Frequency covered = speed of sound divided by twice the depth.  Example:  13,200 inches/second (speed of sound at sea level) divided by 2 divided again by say 3 inches = 2,200 Hz.  So most commercial diffusors could (if acoustically opaque/reflective) only be effective for the highest 3 octaves of human hearing.  And the depths should vary randomly to provide full coverage of the frequency range in question.


The best DIY diffusors I've found:  http://www.pmerecords.com/Diffusor.cfm  Being made of blocks of wood mounted to plywood, they are very heavy in large panels (roughly 10 pounds per square foot).  Painting the blocks would increase effectiveness (just visit a room before and after drywall is painted and slap your hands to test this idea).


According the Floyd Toole's "Sound Reproduction" diffusion works best on side walls.  And don't expect a tiny panel (like a 2ft x 2ft) to provide much benefit.  I use 3 tall randomly filled bookcases along the side walls (like Toole uses at home) that are aesthetically pleasing and functional.

[rodge827]

According the Floyd Toole's "Sound Reproduction" diffusion works best on side walls.  And don't expect a tiny panel (like a 2ft x 2ft) to provide much benefit.  I use 3 tall randomly filled bookcases along the side walls (like Toole uses at home) that are aesthetically pleasing and functional.

JLM, can you post a pic of your bookcases and mention positioning in the room?

Thanks,

Chris

[Bob2]

Seems like there was a previous thread regarding this material.. The consensus was, as JLM mentioned not ideal for acoustic purposes.

[Sonny]

Thank you all, I thought that was what the consensus would come back with...  I was just trying to put off building diffusers...looks like I am going to have to build some! 

I assume for the front and back walls, nothing less than say 2x4 feet panels would be effective, right? 

And for first reflection, should it be absorption or diffusion?

[JLM]

Chris,

My bookcases are nice looking but cheap 30" x 72" x 12" cherry 5 shelf units containing books, papers, and some odds & ends.

[usp1]

Would those paper tiles work if the backside was filled with spray insulating foam? They seem like a very attractive design and if there is a cheap way to enhance their acoustic properties (either absorption or diffusion) they could be a very eye pleasing design and would not require as much work.

[JLM]

Would those paper tiles work if the backside was filled with spray insulating foam? They seem like a very attractive design and if there is a cheap way to enhance their acoustic properties (either absorption or diffusion) they could be a very eye pleasing design and would not require as much work.

Doubt if foam would make a big difference.  Lightweight concrete would be a better material IMO, but doubt it would adhere for long.  And you'd still have limited effective frequency range.

[JWL.GIK]

Looks like you're getting good information. One clarification, though, about well depths. If you are going for a QRD design, then the wells aren't random depths, but rather are precisely calculated to deliver diffusion, defined as even scattering in all directions. While things like bookcases can help scatter some sound waves, and are certainly better than a flat, reflective surface, you can't really say that a bookshelf provides actual diffusion.

There are several online QRD calculators to help you determine which sequence/pattern to use and depths of each well to get the results you are looking for. 

[rodge827]

Chris,

My bookcases are nice looking but cheap 30" x 72" x 12" cherry 5 shelf units containing books, papers, and some odds & ends.

Thanks JLM 

[Sonny]

Doubt if foam would make a big difference.  Lightweight concrete would be a better material IMO, but doubt it would adhere for long.  And you'd still have limited effective frequency range.

Jim,

Really, you don't think that the CRL foam, acoustic foam, designed for small or make shift studios would work?  I think they would, but maybe not as well as well designed wood diffusors or professional absorbers, right?

How about foam corner bass traps?  Sure they won't trap the low frequencies, but perhaps those in the 80hz and above?
https://www.amazon.com/Set-Acoustic-Studio-Soundproofing-Corner/dp/B012BJW9NI/ref=sr_1_1?s=musical-instruments&ie=UTF8&qid=1485803513&sr=1-1-spons&keywords=foam+bass+trap&psc=1

Something like this...
 https://www.amazon.com/Acoustic-Foam-2-1-24-18/dp/B0002ZPLP2

[Bob2]

"Really, you don't think that the CRL foam, acoustic foam, designed for small or make shift studios would work?"
I have tried some of the foam products. None of it seemed to do much. Those items that I purchased from Gik and the DIY units using Owens Corning 703 have worked quite well.

[Sonny]

"Really, you don't think that the CRL foam, acoustic foam, designed for small or make shift studios would work?"
I have tried some of the foam products. None of it seemed to do much. Those items that I purchased from Gik and the DIY units using Owens Corning 703 have worked quite well.

Thanks Bob!

[max190]

Sonny, I still use some Sonex 24x48x2 panels for my 1st and 2nd reflection points that do make a difference. I bought (11) of these http://www.thefoamfactory.com/acousticfoam/bassbroad.html and put (3) in each corner, and then straddled the corners with GIK 244's.

These corner units helped tighten up the bass and really cut down on slap echo. After adding the corner 244's, I mounted another 244 horizontal centered on the front wall, and another 244 directly behind the LP. Adding the GIK's took the room up a couple levels for the better. My next step is replace the Sonex with GIK 242's and add scatter plates to them.

[Sonny]

Sonny, I still use some Sonex 24x48x2 panels for my 1st and 2nd reflection points that do make a difference. I bought (11) of these http://www.thefoamfactory.com/acousticfoam/bassbroad.html and put (3) in each corner, and then straddled the corners with GIK 244's.

These corner units helped tighten up the bass and really cut down on slap echo. After adding the corner 244's, I mounted another 244 horizontal centered on the front wall, and another 244 directly behind the LP. Adding the GIK's took the room up a couple levels for the better. My next step is replace the Sonex with GIK 242's and add scatter plates to them.

Thank you for the information.  In reading the technical data on the corner bass absorbers, seems like they really only work from 125hz up to 4000hz, being most effective at 250-500hz, with a coefficient of 1.27 and 1.26, respectively....

http://www.thefoamfactory.com/acousticfoam/bassbroadNRC.html

Unfortunately, these are not the frequencies I am aiming to reduce...