The sound of diffusion

[Ethan Winer]

Originally Posted by myfipie

Well with the mike that close to the wall I would say it's not the "true" sound but more of the diffusor. I think it is worth pointing out that I don't think Ethan is trying to be all scientific with this test (Ethan correct me if I am wrong). All Doug (the guy jamming the blues) would need to do is move to the left or right, just a little and the sound would have changed. But I think it is great Ethan went through all of this to show the different sounds.

Yes Glenn, exactly. In fact, Doug suggested that I try moving the microphone while he played, so people could hear how the sound changes. But I wanted to keep it simple, since my main goal was to give folks some way to hear what diffusion does and how it sounds.

--Ethan

[miqer]

Thanks! 2 questions:

1. Is the mic pointed to the wall (diffusor, absorber) or the guitar? (Sorry, a bit blind here)

2. What is on the other side, on the wall we are not seeing?

thanks,
miq

[Ethan Winer]

Originally Posted by miqer

1. Is the mic pointed to the wall (diffusor, absorber) or the guitar?

The microphone was pointed at the guitar, as explained in the text to the left of the video links.

What is on the other side, on the wall we are not seeing?

That's a sheet rock wall filled with insulation - one of the side walls in my studio room. On the other side is a staircase.

--Ethan

[Glenn Kuras]

Quote:
Originally Posted by myfipie
Well with the mike that close to the wall I would say it's not the "true" sound but more of the diffusor. I think it is worth pointing out that I don't think Ethan is trying to be all scientific with this test (Ethan correct me if I am wrong). All Doug (the guy jamming the blues) would need to do is move to the left or right, just a little and the sound would have changed. But I think it is great Ethan went through all of this to show the different sounds.

Yes Glenn, exactly. In fact, Doug suggested that I try moving the microphone while he played, so people could hear how the sound changes. But I wanted to keep it simple, since my main goal was to give folks some way to hear what diffusion does and how it sounds.

--Ethan

Note to self: It is spelled MIC not MIKE.

Glenn

[Ethan Winer]

Originally Posted by Glenn Kuras

Note to self: It is spelled MIC not MIKE.

Depends who you ask.

[Jason Jones]

Originally Posted by SpiderM69

So, Ethan, a few questions.

How would you compare your diffusors to the Auralex SpaceArray, other than the obvious difference of bass trapping included?

For the smaller room version (<6 ft), how much distance is needed for the diffusor to be effective?

The auralex SpaceArray doesn't do much until 1500-2000hz. (http://www.auralex.com/testdata/test/mastertable.pdf)

As to the minimum distance from a diffuser: Bryan, if you are out there, let's hear your thoughts on that after the RMAF show.

Jason

[Koed]

Hi Ethan,

Great video as always, I think realtraps and yourself are probably the single point of information about acoustic treatment that makes any sense to me. I've had a lot of 'yes, ofcourse' moments after your videos thumbsup

It's a shame you don't sell the diffusor without the bass trap.
My room has plenty of bass trapping and what I'm really looking for is an affordable diffusor.

[bpape]

We had the sweet seat set about 5-6 feet from the diffusors (an array of 4 on the rear wall of the room). In the past, that wall has always been an issue. This year was a different story. They made a ton of difference.

Moving up farther presented even more benefit as they had room to really work but even at the shorter distance in the back row (3 feet or so), they definitely had an impact on the sound.

Bryan

[SpiderM69]

At the GIK site you talk about placing diffusion high up. Is this for slap/flutter echo only? My ceiling slopes up from 8' to 15' over a distance of 11', so I'm wondering if placing diffusion high up on the higher wall would be of greater benefit than lower, if the goal is to reduce boxiness and create a sense of greater space. (My guess is you're going to say place it low and high )

[Ethan Winer]

Originally Posted by Koed

I've had a lot of 'yes, ofcourse' moments after your videos thumbsup

Excellent, thanks!

It's a shame you don't sell the diffusor without the bass trap. My room has plenty of bass trapping and what I'm really looking for is an affordable diffusor.

It's impossible to make any room perfectly flat, so the more bass traps you have, the closer to flat you'll get. Or in other words, more bass trapping is always welcome. I can't help you with the "more affordable" part unless you want to buy ten of them.

But if our diffusor costs more than you're willing to pay, and you're willing to forgo the bass trapping, Glenn's (GIK) are worth a look.

--Ethan

[berettarsenare]

Hi Ethan, I saw your diffusers and there's something I really like: The wells are divided between them, I red the famous AES paper by D'Antonio and Konnert and there is a nice theoretical work but in all calculations, wells are supposed to be divided but you can find some RPG QRDs without that division (anyway skylines sound great).

And there's another thing I don't like: They are 1D, I think 1D are nice for big rooms but I prefer 2D for small ones, don't you?

As a technician I believe everything can be measured, now we have ISO-17497to measure sound scattering properties of surfaces and measurements seem to say v.g. policylindrical difussers work properly but they don't sound as good as a good difusser, what do you think about that?

Thanks for reading my terrible english until the end, regards.
Berettar.

[Dzoing]

I too thought that 1D diffusors were more suitable for big sized rooms, and 2D (like RPG's) for smaller ones.

Any comment about this?

[Ethan Winer]

Originally Posted by berettarsenare

And there's another thing I don't like: They are 1D, I think 1D are nice for big rooms but I prefer 2D for small ones, don't you?

In rooms the size most of our customers use, 1D makes more sense because it doesn't "waste" the diffusion sending it up into the ceiling and and down into the floor.

--Ethan

[Scott@RealTraps]

Originally Posted by Glenn Kuras

Note to self: It is spelled MIC not MIKE.

Glenn

Actually, Glenn . . . Merriam-Webster's Dictionary (which is the only true DIRECT descendant of Noah Webster's Dictionary, and is deemed by most professional editors, etc. to be the most reliable, authoritative dictionary other than the Oxford English Dictionary) recognizes BOTH "mic" and "mike" as legitimate forms.

The word spelling "mike" has been in use since 1924, with the word spelling "mic" having only been in commonly accepted use since 1961.

The words "miking" and "miked" are generally deemed more correct forms than some of the other abominations such as "micing", "mic'ing", "mic'd", etc. These are actually rather improper contractions/abreviations of words, because the contraction leaves out a critical letter after the "c" (either a consonant or a vowel) that attributes the "c" with either a hard sound (like "k") or soft sound (like "s").

A little word trivia for ya there!

BTW, if you ever need to quickly look up a word in the dictionary, the most up-to-date version (sometimes more up-to-date than the latest print edition) of Merriam-Webster's Collegiate Edition can always be accessed at Merriam-Webster Online.

[berettarsenare]

Originally Posted by Ethan Winer

In rooms the size most of our customers use, 1D makes more sense because it doesn't "waste" the diffusion sending it up into the ceiling and and down into the floor.

--Ethan

I don't know why diffusing in the vertical axis is "wasting". Probably in large spaces where rooms are big, height is not and there's a lot of surface to cover with diffusers it's a good idea to use only 1D but in small ones you can get even more than -3dB in each reflection comparing 2D to 1D.

Thanks, Berettar.

[SpiderM69]

Originally Posted by Ethan Winer

In rooms the size most of our customers use, 1D makes more sense because it doesn't "waste" the diffusion sending it up into the ceiling and and down into the floor.

--Ethan

Ethan, what is the size you're referring to vis a vis your customers? Is that primarily small or larger rooms?

[SpiderM69]

I'm going to ask this question again.

The GIK site talks about placing diffusion high up. What are the benefits of this?

Another way to ask this question might be, is it better to diffuse the source, or is it better to diffuse the reflections?

[Jason Jones]

Originally Posted by SpiderM69

I'm going to ask this question again.

The GIK site talks about placing diffusion high up. What are the benefits of this?

Another way to ask this question might be, is it better to diffuse the source, or is it better to diffuse the reflections?

When you say, "diffuse the source" do you mean the direct early reflection points?

Clearly the early reflection points need to be dealt with in some fashion. But, remember that your speakers are hitting much of your walls just like it hits the early reflection points. The diffuser will redirect that to the listener in the same manner that it would from an early reflection point.

Diffusers can also help to even out the decay times in the room. There is a BBC paper that has a pretty good explanation of diffuser use on the ceiling and problems with differing decay times for vertical reflections vs. horizontal reflections.

Finally, diffusers set-up in these alternate spots can also help with low-frequency problems.

Jason

[Jason Jones]

Originally Posted by SpiderM69

At the GIK site you talk about placing diffusion high up. Is this for slap/flutter echo only? My ceiling slopes up from 8' to 15' over a distance of 11', so I'm wondering if placing diffusion high up on the higher wall would be of greater benefit than lower, if the goal is to reduce boxiness and create a sense of greater space. (My guess is you're going to say place it low and high )

We recommend covering the walls, ceiling and most of the floor with our products. Many people find that stacking diffusers to use as a chair also helps out.

Where to put diffusers depends quite a bit on room size and use? So, what are your room dimensions and what are you using it for?

Jason

[Ethan Winer]

Originally Posted by berettarsenare

I don't know why diffusing in the vertical axis is "wasting".

As I see it, you might as well use absorption rather than scatter sound off toward the floor and ceiling. But there's no hard and fast rules, so if you already have a preference for 2D I won't call you wrong.

--Ethan

[Jason Jones]

Originally Posted by Ethan Winer

As I see it, you might as well use absorption rather than scatter sound off toward the floor and ceiling. But there's no hard and fast rules, so if you already have a preference for 2D I won't call you wrong.

--Ethan

I think the issue is how strong of a reflection do you want. The closer you are to the reflection point, the weaker reflection you will want. Also, from the front of the room you tend to want weaker reflections.

A 2-D diffuser will give a weaker reflection and allow you to be closer than a 1-D. However, 2-D's do not have near the low-frequency effects of 1-D's (at least what is currently available).

Jason

[Ethan Winer]

Originally Posted by Jason Jones

The closer you are to the reflection point, the weaker reflection you will want.

Good point.

--Ethan

[Glenn Kuras]

Originally Posted by Jason Jones

I think the issue is how strong of a reflection do you want. The closer you are to the reflection point, the weaker reflection you will want. Also, from the front of the room you tend to want weaker reflections.

A 2-D diffuser will give a weaker reflection and allow you to be closer than a 1-D. However, 2-D's do not have near the low-frequency effects of 1-D's (at least what is currently available).

Jason

Just FYI - Jason is the person who designed our new D1 diffusor. So if any of you have any diffusion questions, now would be the time to ask while we have his attention.

Glenn

[Bob Ross]

Originally Posted by greatgreatriver

The dolls made me scared - first I thought it was real people but they didn't move to the music so I was forced to think again and after a while the camera zoomed in on the dolls and I could see it was not real people.

Wow. That is a cool sentence.

I would love to use that sentence verbatim as a response to...well, to almost any question that came up on an internet forum or message board!

EG,

OP: "What do you think of the Alesis compressor?"
ME: "The dolls made me scared - first I thought it was real people but they didn't move to the music so I was forced to think again and after a while the camera zoomed in on the dolls and I could see it was not real people."

Or

OP: "The New York Times is making a mockery of evangelical christians!"
ME: "The dolls made me scared - first I thought it was real people but they didn't move to the music so I was forced to think again and after a while the camera zoomed in on the dolls and I could see it was not real people."

[Zuewi]

Do you use the diffusion panels also on vocals? does it sound good? Or is absorber panel better there?

[Glenn Kuras]

Originally Posted by Zuewi

Do you use the diffusion panels also on vocals? does it sound good? Or is absorber panel better there?

Sure, but again it depends on rooms size. You would not want to use diffusion in a vocal booth.

Glenn

[jayfrigo]

Originally Posted by Glenn Kuras

Sure, but again it depends on rooms size. You would not want to use diffusion in a vocal booth.

Glenn

Big enough booth or small enough diffusor and you could.... OK, I'm being tweaky! But diffusors can be designed in a multitude of ways to cover different frequency ranges and fit into whole room plans to satisfy a number of conditions. RPG's flutter free is a diffusor, albeit a very small one that works only at pretty high frequencies by comparison to the traditional, commercially available ones. Still, it could have use in the proper size booth if you take other steps to control the frequencies below its range and plan enough absorption in other areas. But your point I think is that you wouldn't put something like the typical QRD in a 4x5 booth, and that's certainly true!

[Glenn Kuras]

Originally Posted by jayfrigo

Big enough booth or small enough diffusor and you could.... OK, I'm being tweaky! But diffusors can be designed in a multitude of ways to cover different frequency ranges and fit into whole room plans to satisfy a number of conditions. RPG's flutter free is a diffusor, albeit a very small one that works only at pretty high frequencies by comparison to the traditional, commercially available ones. Still, it could have use in the proper size booth if you take other steps to control the frequencies below its range and plan enough absorption in other areas. But your point I think is that you wouldn't put something like the typical QRD in a 4x5 booth, and that's certainly true!

I see your point, MR TWEAKY. But I would recommend in a 4x5 vocal booth to just absorb. Diffusion would be of little use or room left for it. But if you want to tweak that far then hey I ain't stopping you.

Glenn

[SpiderM69]

Originally Posted by Jason Jones

When you say, "diffuse the source" do you mean the direct early reflection points?

Clearly the early reflection points need to be dealt with in some fashion. But, remember that your speakers are hitting much of your walls just like it hits the early reflection points. The diffuser will redirect that to the listener in the same manner that it would from an early reflection point.

Diffusers can also help to even out the decay times in the room. There is a BBC paper that has a pretty good explanation of diffuser use on the ceiling and problems with differing decay times for vertical reflections vs. horizontal reflections.

Finally, diffusers set-up in these alternate spots can also help with low-frequency problems.

Jason

Jason, thanks for the response.

I do mean diffuse the early direct reflection point(s), and I'm referring to tracking (the original subject of this thread).

A very basic way to put this is if I'm recording an acoustic guitar, and becasue I can't afford to put diffusion on all walls (which may not be desirable anyway), is it best to "point" the guitar at the diffusor, albeit from a few feet back, or is it best to point the guitar away from the diffusor (therefore a cardiod mic recording the guitar would be pointed generally in the direction of the diffusor)? Bass trapping is assumed.

This is what I mean by diffusing the source vs diffusing the reflections (later early reflections?). I would think that the purpose of diffusion, when used in small/smaller rooms and attempting to achieve less boxiness/greater perception of space/better frequency balance, what's important is diffusing the early reflections but not the initial direct reflection?

Hopefully this makes sense, I'm interested in the general principal.

Thanks,

[sleestack]

Stupid question, but how are thse dedicated diffuser and bass traps etc. better than hanging up some carpets? For the poor folk