Is diffusion dead?

On this forum? Is it just a matter of school, or thought? Not many likers here Lets start a debate

Diffusion takes up valuable absorption areas. Most studios on this forum are small and need maximum bass absorption, so that why there not many takers. I don't think it's dead, it just compromise.

I agree with Lilith: It's not dead, just not very useful in small studios. Larger places sure can make good use of it. IMHO - Stuart -

Even in larger designs of John he doesnt use any diffusion, I think in his case its just a matter of "school". Am i wrong?

Even in larger designs of John he doesnt use any diffusion,

Well, I may be wrong here, but I recon that John's famous slot resonators will provide a bit of diffusion in the room, even though they aren't really diffusors in the normal sense. The front faces of the slats and the "wells" in the slots have to have some kind of diffusing effect, I reckon. On the other hand, John's designs don't really need traditional diffusion, since they provide a great balance of reflection and absorption anyway. I'm sure I'll get flamed for saying this, but to me it seems that diffusion in a studio is a kludge to fix a problem that shouldn't have been there anyway! If the studio had been designed right to start with (as is the case with John's designs), then you just don't need any additional diffusion. - Stuart -

Good discussion. Don t know if it s a matter of "school" but I think that many studios were I ve been are too dead for me. This is why I go with a control room "the old way". it s a small CR (6mX4) but it will be kind of "LEDE" dead in front (till 1m behind the good mixer position) & live behind. But it s more work ... especially when you come from music and want to do a diy rec stud. Zen :D

jbassino wrote:

Not many likers here

The more I play around with diffusion, the more I like it. Small rooms benefit greatly too. Probably more than many realize. I recently decked out a bedroom size space with a ton of diffusion, and IMO it sounded much better than using only absorption. You can listen and decide for yourself with this video: Hearing is Believing There's also this video which lets you hear diffusion used close up: All About Diffusion --Ethan

When you say small room...your referring to one with a 16 foot long dimension? Your video uses that number as a base. I think it is common to accept that 12 feet is the boundary marker isn't it?

Soundman2020 wrote:

I agree with Lilith: It's not dead, just not very useful in small studios. Larger places sure can make good use of it.

+1. In addition, as has already been presented in this thread, many small studio designs here do have diffusion. It is just not achieved with Schroeder type diffusors. John's excellent absorbers with slat fronts a perfect example. Andre

xSpace wrote:

When you say small room...your referring to one with a 16 foot long dimension?

Sure, that's a small room.

I think it is common to accept that 12 feet is the boundary marker isn't it?

It depends on the depth of the diffusor. But I've seen QRD diffusors used in very small spaces to good advantage. If you watch my video All About Diffusion you'll see diffusors placed very close to acoustic instruments on purpose at Skywalker Sound. --Ethan

Well. Its still in debate ! Ethan says it sounds good even in small rooms (thing that I've heard before as well) Some others says it doesnt. Once I heard a guy that designs acoustic eviroments here in CHile that EU and the US had different schools for aproaching acoustic treatment. Some like diffusion and others absorptions. Either way I think you can get to the same results. If you ask me, I still believe its a matter of school Actually, as a matter of fact, There is one studio here in Santiago that was designed by Eastlake . Its beautifull but its 100% absorption. Either the Control Room and the Live room are covered 90% by cloth walls. IMO I think it sounds too damn dead

jbassino wrote:

Well. Its still in debate !

What debate? As I erote in my first post in this thread. Diffusion is present in most room designs on this site. The diffusion is not acheived by methods that are recognized by many for diffusion, but it is clearly used. Andre

In that case diffusion its achieved just "by chance" since you can't predict what kind of frecuencies will be diffused, plus my guessing is that it will be mostly on high frecuencies.

jbassino wrote:

In that case diffusion its achieved just "by chance" since you can't predict what kind of frecuencies will be diffused, plus my guessing is that it will be mostly on high frecuencies.

??? Graduate and advanced under-graduate level acoustics texts detail diffusion at hard edges as a function of the wavelength.

In that case diffusion its achieved just "by chance" since you can't predict what kind of frecuencies will be diffused,

I don't think it is "by chance" at all, and it can be predicted. Acoustics is far more science and far less art than it used to be. I'm not really up to speed on the math (although I'm sure André is!) but it doesn't look like it would be too hard to figure out what happens, in terms of diffusion, on John's "slot wall" design. Hard surfaces with sharp edges, known dimensions, etc. For someone with better math skills than mine, it shouldn't be too hard to predict what happens. Then again, for math-challenged folks like me, we can just go listen in such a room, and hear what is going on! The proof that it works, and is broadband, is right there in your ears. Your own live room is a case in point, Javier: it sounds so good mostly because of the diffusion coming of John's slot wall design. If it wasn't for that diffusion, it would not sound anywhere near as good. I guarantee that if you took off a few of those slats, the sound would change dramatically, for the worse: It would end up muddy and dead. Probably just taking off less than half a dozen slats would already cause some serious damage to the diffusion. I don't think John achieved that design by chance. I'm just guessing here, but I reckon he came up with that design partly from his years of experience and knowledge of rooms, but mostly from calculation. There's a reason for those measurements, and it isn't just aesthetics, I imagine! - Stuart -

I don't mean to mean that I don't agree with everything you just have said Stuart. But in the other hand. its like saying that Panel Absorbers are diffusers as well because of the hard edges from the wooden frame. Everything that is just not flat will diffuse in any or another way. The intention about this post was to talk about devices intented to do diffusion like QRD ,skylines, the ones that Ethan sells, which lacks of use on this forum. Thats all!

"I don't think it's dead, it just compromise." Grounds for divorce if I recall;) I am not even going to act like I know something about acoustics...but: The small rooms that we are all so used to seeing (less than 1500 cubic feet) here @JS are most likely, based on what those of you strong in acoustics have pointed out supported with strong acoustical data, the reason why diffusion as a practice does not get much support. Everything that is attempted here, at least that I have come to appreciate and learned at this site, the splaying of walls, inclined ceilings, pain in the butt attention to ratios of rectangular rooms...help me out here, ..it's all about creating as diffuse a field as possible. So that being part of the process..it seems that diffusion is being forsaken, but it is not, it is given a different shape. I still do not think that a typical small bedroom (a wall of less then 12 feet in length as part of the dimension) can achieve anything that remotely resembles a diffuse environment especially, as Lilith brought to our attention, when the space for absorption is required so desperately.

xSpace wrote:

..it seems that diffusion is being forsaken, but it is not, it is given a different shape.

+1 :!: Andre

Ethan, How do your diffusors act as absorbers under 800hz? Forgive me if I'm asking for a trade secret. :oops: But if you don't ask....you're certain to never find out.

grits wrote:

How do your diffusors act as absorbers under 800hz?

The exact materials are a "trade secret" but the general idea is not. In fact, you can even see some diffusors being built in our factory tour video: Made in Connecticut Basically, the wells are made of reflecting but thin material, and rigid fiberglass is behind that. --Ethan

Thank you Ethan. All your vids are time well spent for me.

Ethan one question why did you design your diffusers too have absorption to such a high freq 800hz or 600hz is way too high in my opinion could you please explain this decision

valentin wrote:

why did you design your diffusers too have absorption to such a high freq

The "crossover" frequency is determined mainly by the lower limit of the diffusors. It's not a hard transition, and I promise you they sound great. Besides the video All About Diffusion I mentioned above, our Hearing is Believing demo also lets you hear them in action. Even more important, look at how much more uniform the RT60 decays become with our diffusors versus bare walls. I'm not trying to brag about my company's diffusors! But you did ask. --Ethan

i don't mind you bragging about your product i think you have done a great job in promoting better acoustics all over i have followed you for quite some time and yes i did ask i am very much in pro of a diffuse sound field ( or what can be accomplished in a small room "not much") something you didn't promote with products in the beginning but now you do and i am glad of it and believe you that diffusion helps i support it but i also think you need diffusion to at least 300 hz to create as much envelopment as possible just a point of view :) slat absorber also can also produce a "diffuse sound field" , Les efficiently than other systems but thy do in less space

valentin wrote:

but i also think you need diffusion to at least 300 hz to create as much envelopment as possible

Another issue is that very deep diffusors that work to that low a frequency cannot be shipped economically. FedEx can deliver our diffusor anywhere in the US for about $50 or less. Going even a little larger increases the shipping cost a lot. Regardless, the results shown in our Hearing is Believing video show how effective even six inches of depth can be. Even our "near" model, with wells only three inches deep, sounds infinitely better than a bare wall. --Ethan