Polyfusiors - The Truth

[spencerc]

Hello All,

I just wanted to make sure the "bad rap" some people have given polyfusiors doesn't go on without people hearing the truth - and not just believing what is shown for instance on a "home" test demonstration video.

Acutal quote from "Master Handbook of Acoustics" by F. Alton Everest

Page 286 - Under the paragraph header "Convex Surfaces: The Poly"

"One of the most effective diffusing elements, and one relatively easy to construct, is the polycylindrical diffusor."

Some would argue that poly's are bad because of the "concave" surface they create. Firstly, you can create monocylinders, so that there are no concave surfaces, and space them out in the room. Secondly, you would NEVER put a microphone in the concave portion of a bicylinder poly. Everyone knows microphone placement is crucial to getting a good sound. Diffusors are meant to diffuse sound a few feet away from them (which is where the mic should be...not right next to the diffusor).

If anyone wants to add to this thread, please do. My intention is only to educate and set the record straight with Poly fusiors.

If you wonder what caused me to start this thread, PM me and I'll send you a link.

[Ethan Winer]

Originally Posted by spencerc

Acutal quote from "Master Handbook of Acoustics" by F. Alton Everest

Yes, but the kind of rooms Everest refers to and shows are much larger than the rooms most Gs'ers are using to record and mix in. Page 212, Figures 9-26 and 9-28 (4th edition) show photos of a poly wall in a theater size room. Diffusion requirements in a large room like that are very different than for a bedroom size space!

Some would argue that poly's are bad because of the "concave" surface they create. Firstly, you can create monocylinders, so that there are no concave surfaces, and space them out in the room.

Yes, that someone would be me. If you try to solve the concave problem by spacing the ploys apart, you no longer have a continuous diffusing wall. You have only half a diffusor.

If you wonder what caused me to start this thread, PM me and I'll send you a link.

No need for PMs, and that defeats the whole point of a public forum. Here ya go:

All About Diffusion

As clearly explained in the video, the recording microphone was placed very close to all the surfaces to exaggerate their effect, making it easier for viewers not present in the room to hear what each surface sounds like.

I'll also add that "argument from authority" by quoting Everest is not productive. Clearly Everest was an authority, and his work advanced acoustics and made the topic accessible to many people who would not be able to get through formal books filled with math. But that book was written in another time and place, and much of what he wrote does not apply today. For example, nowhere in that book will you see bare 4-inch thick rigid fiberglass panels straddling corners! Time marches on, and the state of the art advances as we learn new things.

--Ethan

[spencerc]

Originally Posted by Ethan Winer

Yes, but the kind of rooms Everest refers to and shows are much larger than the rooms most Gs'ers are using to record and mix in. Page 212, Figures 9-26 and 9-28 (4th edition) show photos of a poly wall in a theater size room. Diffusion requirements in a large room like that are very different than for a bedroom size space!

Ok, yes I can see some truth to your point, but from your video, it makes it seem like poly fusiors are far inferior to your QRD's. Secondly, if your bedroom sized space is THAT small, I'd say you should be using mostly absorption rather than diffusion. Diffusion is meant to work a couple of feet away from from the diffusor, and so of course you will get skewed resluts if you are too close to the diffusor.

Originally Posted by Ethan Winer

Yes, that someone would be me. If you try to solve the concave problem by spacing the ploys apart, you no longer have a continuous diffusing wall. You have only half a diffusor.

Ok, but by putting a bunch of the same QRD's in a row to form a continuous diffusion wall, you diminish their ability to diffuse because of the repetivite nature of the sequence. That to me = a waste of money (espeacially at $500 per 8 sq feet). So in both cases, we are not looking for a totally diffusive wall (nor did I ever state that I wanted a totally diffusive wall). That is not the point of the post - The point is that a poly can be used as a great diffusor when implimented correctly.

Originally Posted by Ethan Winer

All About Diffusion

As clearly explained in the video, the recording microphone was placed very close to all the surfaces to exaggerate their effect, making it easier for viewers not present in the room to hear what each surface sounds like.

That is totally irrelevant - microphone placement has such a huge impact on the sound. Why on earth would you mic a guitar with the mic pointed in the concave surface of the poly?

For example - a SM57 and a U87 both placed inside a saxophone will sound like crap. To do a real test to see which mic sounds better, mic the saxophone properly. That would be a relevant test. Diffusers are meant to diffuse sound away from them - and it takes a couple of feet before you will properly hear the sound that is meant to be heard from the diffuser. micing the diffuser (or the concave surface for that matter) gives TOTALLY skewed results.

I challenge you to do a true test with a microphone recording a guitar (micing the guitar and not the diffuser) while playing a few feet away from each diffuser. If the differences are really that small that you have to be "up close" to the diffuser to hear them, can that really justify spending a lot more money? After all, as you said yourself - these are for small "bedroom" sized budget project studios, not huge theater sized rooms with massive budgets.

Originally Posted by Ethan Winer

I'll also add that "argument from authority" by quoting Everest is not productive. Clearly Everest was an authority, and his work advanced acoustics and made the topic accessible to many people who would not be able to get through formal books filled with math. But that book was written in another time and place, and much of what he wrote does not apply today. For example, nowhere in that book will you see bare 4-inch thick rigid fiberglass panels straddling corners! Time marches on, and the state of the art advances as we learn new things.

Firstly may I just say, wow...you are shooting yourself in the foot among the professional acoustics community by discregarding this book. I don't know of a professional designer who hasn't read it or used it. Is Rod Gervais' book, "Home Recording Studio: Build it Like the Pros" irrelevant too?

Why are you so down on math Ethan? That's what acoustics is about...math and physics. You can't argue that.

If you plan and build a properly designed room from the start, bass trapping can be achieved without extensive use of fiberglass straddling corners. I'm not arguing that fiberglass doesn't work. I'm just saying it doesn't have to be the only option. If you want an example, talk to Avare...he can give you some details on how to properly design a room.

As far as "much of what he wrote does not apply today"...I just feel sad for you if that is what you truly believe. That book is a wealth of information - and I recommend anyone who is planning/designing a studio should read it.

I'm in no way trying to attack your product line Ethan - All I wanted to do was make clear that Poly Fusiors do work, and that QRD's arn't the only option (especially for us that are budget conscious).

-Spencer

[Ethan Winer]

Originally Posted by spencerc

from your video, it makes it seem like poly fusiors are far inferior to your QRD's.

Polys are inferior to QRD diffusors in smaller rooms. Look at pictures of any current state of the art studios designed by Wes Lachot, Fran Manzella, and the other "with it" big names, and you'll see a row of QRDs along the rear wall. Not a row of polys.

Why on earth would you mic a guitar with the mic pointed in the concave surface of the poly?

Between calling my company's diffusors a waste of money and saying you feel sad for me, it appears you're being intentionally combative and insulting. But I'll give you the benefit of the doubt for now.

I explained clearly in the video why I did that:

All diffusors create audible artifacts. Diffusors are usually placed at least 6 to 10 feet away from instruments, microphones, and listeners. For the purpose of this video we'll be much closer to the diffusors and other surfaces, to magnify their effect making the artifacts easier to hear ... Diffusors are not meant to be used extremely close to a performer, microphone, or listener, but even close up they're much better than a bare reflecting wall.

Most people have no way to hear what a real diffusor sounds like. When you stand directly in front of different surfaces - flat wall, QRD, curved, bookshelves - and talk into them, it's a real eye opener to hear how they reflect. The only way to impart that experience to people through a video is with a microphone close to each surface, to imitate your ears being close to each surface.

--Ethan

[Glenn Kuras]

Take a look at the following thread where we all talked about polys.

Sonotube Diffusor

[jayfrigo]

Thanks for your thoughts on the subject. There have been a few threads here discussing the pros and cons of polys vs. QRDs, and in what applications each is effective, and where each has shortcomings. Neither is perfect in all situations, and both have applications where they shine wonderfully.

I don't think they get a bad rap around here. I think both poly and QRD have had plenty of good AND bad things said about them. If a reasonable person reads the threads, I think they can see both sides of the story and learn quite a lot about proper use of each.

Though Everest is a great source, there are several other sources, several more recent and detailed, that discuss both styles of diffusion, and others as well. A single quote, however useful, is only a small part of the story. It does seem odd that this thread would come out of nowhere. Polys undeniably have shortcomings, as do QRDs. That's nothing to get upset about. Knowing what the shortcomings are, and how to properly implement installations to minimize the shortcomings is the education I prefer to focus upon.

Originally Posted by spencerc

Hello All,

I just wanted to make sure the "bad rap" some people have given polyfusiors doesn't go on without people hearing the truth - and not just believing what is shown for instance on a "home" test demonstration video.

Acutal quote from "Master Handbook of Acoustics" by F. Alton Everest

Page 286 - Under the paragraph header "Convex Surfaces: The Poly"

"One of the most effective diffusing elements, and one relatively easy to construct, is the polycylindrical diffusor."

Some would argue that poly's are bad because of the "concave" surface they create. Firstly, you can create monocylinders, so that there are no concave surfaces, and space them out in the room. Secondly, you would NEVER put a microphone in the concave portion of a bicylinder poly. Everyone knows microphone placement is crucial to getting a good sound. Diffusors are meant to diffuse sound a few feet away from them (which is where the mic should be...not right next to the diffusor).

If anyone wants to add to this thread, please do. My intention is only to educate and set the record straight with Poly fusiors.

If you wonder what caused me to start this thread, PM me and I'll send you a link.

[spencerc]

Originally Posted by Ethan Winer

Look at pictures of any current state of the art studios designed by Wes Lachot, Fran Manzella, and the other "with it" big names, and you'll see a row of QRDs along the rear wall. Not a row of polys.

I totally agree Ethan - and I never said QRD's are a bad choice. I am simply wanting to state the fact that Poly fusiors arn't all bad. If I had the money, I would be using QRD's all over the place (because they DO sound great!) But Poly's can work too - if implemented right.

I never said Poly's were a good choice for the rear wall of a control room - and thats not what your home test shows them as. I am saying they can be a good cost effective choice in a tracking room setting (but not BETTER or WORSE than QRD's, simply another choice that will work).

Originally Posted by Ethan Winer

Between calling my company's diffusers a waste of money and saying you feel sad for me, it appears you're being intentionally combative and insulting. But I'll give you the benefit of the doubt for now.

--Ethan

Ethan, I did not at all intend to make it seem like your company's diffusers are a waste of money. I think your product line is great! and your diffuser did sound awesome in your test. I have a high respect for your Traps as well...they are an awesome product that sound and look great. All I wanted to do is make it known that Poly fusiors arn't as bad as you made them out to be (especially as a DIY option). By the way, I never mentioned your product line once in my posts...

And yes there have been many updates in acoustics since "Master Handbook of Acoustics" - but I think that you honestly can't regard that book as something that doesn't apply to today. In the 4th version (the one you referred to), there is a whole chapter written by Geoff Goacher of Acoustisoft about room measurement. Is this something that is considered obsolete along with the book? Besides, most of this book is about physics, which haven't changed over time (back to the Math and Physics again). Also, you are forgetting that Everest has a whole chapter on QRD's right after the chapter on Poly's....how can one chapter be obsolete, but not the other?


Jayfrigo, my basis for starting this post was just because I wanted people who are budget conscious, (like myself) to know that Poly fusiors can be a cheap means of diffusion if properly implemented. This is not (in my opinion) how Ethan portrayed it in his video and so that is why I started the thread.

As you stated in your last sentence, "Knowing what the shortcomings are, and how to properly implement installations to minimize the shortcomings is the education I prefer to focus upon" was my motive for this post as well - to educate that poly fusiors can be a great option when used properly.

-Spencer

[Glenn Kuras]

I never said Poly's were a good choice for the rear wall of a control room - and thats not what your home test shows them as. I am saying they can be a good cost effective choice in a tracking room setting (but not BETTER or WORSE than QRD's, simply another choice that will work).

I would say you could use then on the back wall if you have enough room between you and the back wall. So don't think you can't use them there. Also in the control room there is no reason they can not be used in the back 1/3 of the side walls. All and all I myself like the concept of polys when used correctly. Heck we use the poly concept in our new QRD that is coming on the market very soon. Did you see it in the thread that I posted up top?

Glenn

[Jason Jones]

Originally Posted by jayfrigo

It does seem odd that this thread would come out of nowhere.

He is responding to Ethan's video comparing QRD's to Polys. While I understand what Ethan is trying to do, I have to agree that the video is misleading.

To make a fair comparison, Ethan would have to place the microphone inside the well of a QRD. This would make it a valid comparison. However, it would be irrelevant since nobody puts microphones inside acoustical panels when recording. I read Ethan's reasoning on this. But, the acoustical disturbances inside of the panel are not the same as those a foot or two away...it is not merely a matter of decreasing intensity with distance.

Explaining some of the finer points of diffusion can be frustrating and difficult. I know that I have personally bored people into comas (now I stop when their eyes glaze over).

The real nitty gritty of a poly vs. a qrd is going to be related to a whole host of factors: budget, size of the room, overall acoustic plan, personal taste in sound, personal taste in aesthetics, etc. The question is not QRD vs. Poly which is better or worse. The real question is given the factors I mentioned above which panel do you want at spot A on the wall. The use of polys and QRD's in a room together (coexisting in harmony ) is going to be a good solution for lots of people.

Jason Jones

[Ethan Winer]

Originally Posted by spencerc

I never mentioned your product line once in my posts

Actually you said:

Originally Posted by spencerc

That to me = a waste of money (espeacially at $500 per 8 sq feet).

Whose "$500 per 8 sq feet" diffusors did you have in mind as a waste of money if not RealTraps? And why the "PM me" stuff? This is a public forum, not a place to arrange private conversations to set the record straight on "the truth" about someone or something.

I think that you honestly can't regard that book as something that doesn't apply to today.

I said nothing of the sort. What I said was:

much of what he wrote does not apply today. For example, nowhere in that book will you see bare 4-inch thick rigid fiberglass panels straddling corners!

Perhaps I could have said "some" rather than "much," though I don't think "much" is really wrong. The basics are all correct, of course, but studios these days are much smaller than studios back then. There is a lot of new thinking on how to approach small rooms since Everest wrote that book. That's the main reason I wrote A New Approach to Small Room Acoustics for Electronic Musician magazine a few years ago. Because so many people - including professional acousticians - overlooked the unique requirements of small rooms. Before this and other recent articles and videos of mine, the prevailing wisdom was that all peaks and nulls are due entirely to room modes. Now we know that modes are but a subset of the larger issue of comb filtering, and peaks and nulls are just as likely to happen at frequencies unrelated to modes.

In any case, I do not agree that polys are as good as QRD, at least not in small rooms. Even in large rooms QRDs are arguably better. When I was in Studio A at the Hit Factory Criteria in Miami last year I noticed that the entire ceiling was covered with a continuous (repeating BTW) pattern of RPG brand QRD diffusors. That is one of the livest and most natural sounding rooms I've ever been in.

Whatever, thankfully we can now put this behind us.

--Ethan

[Ethan Winer]

Originally Posted by Jason Jones

While I understand what Ethan is trying to do, I have to agree that the video is misleading.

Heh, I don't know how many other ways I can say "Intentionally exaggerated so you can hear what it sounds like close up."

the acoustical disturbances inside of the panel are not the same as those a foot or two away...it is not merely a matter of decreasing intensity with distance.

I don't know why a well resonance a few feet away would be different than a well resonance close up, other than intensity. I do understand the scattering nature of diffusors (duh), but it seems to me the larger benefit in a small room is from the staggered reflection times. This breaks up the coherence of the reflections coming back at you, independent of any scattering.

Explaining some of the finer points of diffusion can be frustrating and difficult. I know that I have personally bored people into comas (now I stop when their eyes glaze over).

Yeah, I freely admit I'm a seat of the pants empirical guy, and my eyes glaze over with this stuff every time. So let's cut it out already, okay?

Thanks Jason, your posts are always valuable.

--Ethan

[spencerc]

Originally Posted by Ethan Winer

Actually you said:

Whose "$500 per 8 sq feet" diffusers did you have in mind as a waste of money if not RealTraps? And why the "PM me" stuff? This is a public forum, not a place to arrange private conversations to set the record straight on "the truth" about someone or something.

Ethan, I never mentioned that the $500 was relating to your products. There are many companies that produce QRD, and most of them cost around $500 - it was meant to be a general estimate. If you want to take it personally, that is your choice.

For example, GIK's new QRD is being released at $599 - but they have implemented poly surfaces within the QRD - a justifiable reason for the extra $99.

By the way, I never said your products were a waste of money - what I said was "Ok, but by putting a bunch of the same QRD's in a row to form a continuous diffusion wall, you diminish their ability to diffuse because of the repetitive nature of the sequence. That to me = a waste of money (especially at $500 per 8 sq feet)". By no means does that mean your diffuser is a waste of money (it is a great product, as I have mentioned before - one which I might be buying myself in the near future for my studio if I can't make my own QRD's) - it simply means that if you were to get to the point where you are loosing sound quality of the diffuser (by the repetitive nature of the sequnce) but still dishing out $500 per 8 feet square feet, you have reached the point of diminishing returns. That is what is a waste of money in my mind.

I wanted to do the PM stuff, because I did not want to try and make your video (or your name) look bad in public - AGAIN, all I wanted to do was make the point that Poly Fusiors can be a great choice if implemented right. The only reason was, as I wrote "If you wonder what caused me to start this thread, PM me and I'll send you a link". This was just in case people though this thread would have come out of nowhere.

Originally Posted by Ethan Winer

I said nothing of the sort. What I said was:



Perhaps I could have said "some" rather than "much," though I don't think "much" is really wrong. The basics are all correct, of course, but studios these days are much smaller than studios back then. There is a lot of new thinking on how to approach small rooms since Everest wrote that book. That's the main reason I wrote A New Approach to Small Room Acoustics for Electronic Musician magazine a few years ago. Because so many people - including professional acousticians - overlooked the unique requirements of small rooms. Before this and other recent articles and videos of mine, the prevailing wisdom was that all peaks and nulls are due entirely to room modes. Now we know that modes are but a subset of the larger issue of comb filtering, and peaks and nulls are just as likely to happen at frequencies unrelated to modes.

I do agree small rooms have unique problems, but I do not agree that this book is outdated. In the words of Ron Burgandy "Well, Agree to disagree".

Originally Posted by Ethan Winer

In any case, I do not agree that polys are as good as QRD, at least not in small rooms. Even in large rooms QRDs are arguably better. When I was in Studio A at the Hit Factory Criteria in Miami last year I noticed that the entire ceiling was covered with a continuous (repeating BTW) pattern of RPG brand QRD diffusors. That is one of the livest and most natural sounding rooms I've ever been in.

That is your choice Ethan, but what facts other than your own personal experience do you have to back this up? ....what about math and physics?

Personal taste is HIGHLY subjective. Also, a room sounding great can not be simply accredited to the QRD's on the ceiling.
[/quote]

Originally Posted by Ethan Winer

Whatever, thankfully we can now put this behind us.

--Ethan

If you want to stop debating about this topic, that is fine. But I want to make sure my point is made, and hopefully it will cause you to take another look at this topic.

Poly diffusers are another option of diffusion that can sound great if implemented right. Not BETTER or WORSE than QRD's, but another option.

I think you'll find most people who have posted so far are in agreement with this view.

- Spencer

[spencerc]

Originally Posted by Ethan Winer

Heh, I don't know how many other ways I can say "Intentionally exaggerated so you can hear what it sounds like close up."

Your missing the point Ethan, you are not exaggerating the true effect of what the Poly diffuser sounds like. As Jason stated:

"To make a fair comparison, Ethan would have to place the microphone inside the well of a QRD. This would make it a valid comparison. However, it would be irrelevant since nobody puts microphones inside acoustical panels when recording. I read Ethan's reasoning on this. But, the acoustical disturbances inside of the panel are not the same as those a foot or two away...it is not merely a matter of decreasing intensity with distance."

I seriously request that if you have time Ethan, to make a video comparing the two diffusers with proper micing technique, and with a proper spacing away from the diffuser. This will show the true differences between the two diffusers (instead of being falsely exaggerated). Hopefully this will help you see that one diffuser can not be considered better or worse than the other.

Originally Posted by Ethan Winer

I don't know why a well resonance a few feet away would be different than a well resonance close up, other than intensity. I do understand the scattering nature of diffusors (duh), but it seems to me the larger benefit in a small room is from the staggered reflection times. This breaks up the coherence of the reflections coming back at you, independent of any scattering.

Acoustics is a highly complex subject, and is very counter intuitive. I myself have only BARLEY scratched the surface of the vast knowledge about acoustics that is out there. If you don't understand something, that's what acoustic books are for. thumbsup

- Spencer

[spencerc]

Originally Posted by Glenn Kuras

I would say you could use then on the back wall if you have enough room between you and the back wall. So don't think you can't use them there. Also in the control room there is no reason they can not be used in the back 1/3 of the side walls. All and all I myself like the concept of polys when used correctly. Heck we use the poly concept in our new QRD that is coming on the market very soon. Did you see it in the thread that I posted up top?

Glenn

Thanks for you post Glenn. I totally agree! And yes I saw your new QRD...it looks fantastic! I can't wait to see one in real life! (and hear it )


I just want to point out that I was basing this thread on Ethan's video about diffusion - where he uses the Poly in a tracking setting. That is why I was confused when he brought up the comment about Poly's being a bad choice for the rear wall of a control room.

I never said you couldn't use Poly's in the control room. I simply wanted to point out to Ethan that he was trying to refer to something that I never wrote.

- Spencer

[spencerc]

Originally Posted by Jason Jones

He is responding to Ethan's video comparing QRD's to Polys. While I understand what Ethan is trying to do, I have to agree that the video is misleading.

To make a fair comparison, Ethan would have to place the microphone inside the well of a QRD. This would make it a valid comparison. However, it would be irrelevant since nobody puts microphones inside acoustical panels when recording. I read Ethan's reasoning on this. But, the acoustical disturbances inside of the panel are not the same as those a foot or two away...it is not merely a matter of decreasing intensity with distance.

Explaining some of the finer points of diffusion can be frustrating and difficult. I know that I have personally bored people into comas (now I stop when their eyes glaze over).

The real nitty gritty of a poly vs. a qrd is going to be related to a whole host of factors: budget, size of the room, overall acoustic plan, personal taste in sound, personal taste in aesthetics, etc. The question is not QRD vs. Poly which is better or worse. The real question is given the factors I mentioned above which panel do you want at spot A on the wall. The use of polys and QRD's in a room together (coexisting in harmony ) is going to be a good solution for lots of people.

Jason Jones

I couldn't agree more Jason!

-Spencer

[Ethan Winer]

Spencer, I'm not going to drag this out further with an extended back and forth, point by point, with you. If you want to argue you're welcome to do it all by yourself. However, I will address this:

Originally Posted by spencerc

I seriously request that if you have time Ethan, to make a video comparing the two diffusers with proper micing technique, and with a proper spacing away from the diffuser.

I already did my homework and gave my best shot at an educational diffusion video. I think it'd be great if you made the follow-up. Then you can do it exactly as you think is best.

--Ethan

[jayfrigo]

Originally Posted by Jason Jones

Explaining some of the finer points of diffusion can be frustrating and difficult. I know that I have personally bored people into comas (now I stop when their eyes glaze over).

I hear ya. It seems that as I have posted in the past that both have pros and cons, some on one side say, "no, mine is perfect," and I'll let you guess what some on the other side say...

It comes down to choosing the right one for the job, and implementing it properly. Some internet users prefer simple rules to complex interactions, and that can cause confusion.

As for Ethan's video, it's just a folksy demonstration showing where he feels his QRDs are useful. No problem there. It is presented from his perspective. If it were a strictly scholarly documentary, then I'd expect more info on other forms of diffusion, and under different conditions. Of course others can pick up the discussion where he leaves off, or even make a more complete video of their own. I give him points for the effort nonetheless.

[spencerc]

Originally Posted by Ethan Winer

Spencer, I'm not going to drag this out further with an extended back and forth, point by point, with you. If you want to argue you're welcome to do it all by yourself.

Sounds good! I doesn't seem like I'm arguing with anyone else on this thread but you, so there is no arguing to be had.

Poly's are a great diffusive option when implemented right. Not better or worse than QRD's.

Originally Posted by Ethan Winer

I already did my homework and gave my best shot at an educational diffusion video. I think it'd be great if you made the follow-up. Then you can do it exactly as you think is best.

--Ethan

If I had one of your diffusers, I gladly would. Would you care to send me one so that I could do a test? ...Don't worry I'm kidding - I don't expect to get your product for free. If I end up ordering some of your diffusers, I will do a test and make a video of it.

That being said...

Your name has a big pull on the acoustics community Ethan, and that's why I think it would be beneficial if you made the video. Many people respect your opinion and look up to you. Who am I to do an acoustic test? Who would watch my video or listen to me? I don't have an acoustic company and I hardly have a name that is even remotely known amount acousticians. How would people take it seriously?

Honestly the test wouldn't be that hard to make. Just set up your diffusers a few to several feet away from your guitar, mic the guitar properly, and hit record. If you don't have the time I completely understand as many of us are very busy these days. I just think it would benefit everyone in the acoustic community to see it coming from you.

I do highly respect that you took the time to make the first video on your own time and money.

- Spencer

[Glenn Kuras]

As for Ethan's video, it's just a folksy demonstration showing where he feels his QRDs are useful. No problem there. It is presented from his perspective. If it were a strictly scholarly documentary, then I'd expect more info on other forms of diffusion, and under different conditions. Of course others can pick up the discussion where he leaves off, or even make a more complete video of their own. I give him points for the effort nonetheless.

I think that is very well said.

I just want to point out that I was basing this thread on Ethan's video about diffusion - where he uses the Poly in a tracking setting. That is why I was confused when he brought up the comment about Poly's being a bad choice for the rear wall of a control room.

I never said you couldn't use Poly's in the control room. I simply wanted to point out to Ethan that he was trying to refer to something that I never wrote.

Gotcha or should I say You Betcha

Really I understand what you are saying and agree with a lot of your points. I am sure Ethan is sitting there reading your comments saying "Well if you don't like it then test it yourself". Ethan is a great guy (had dinner with him in NY) but just like anyone else does not like to be called on his hard work. And TRUST me he has put a LOT of hard work into his videos. Which BTW if you do the test and it comes out well I would be more then happy to post it on our website for people to learn. No we don't sell polys as we are talking about in this thread, but then again it might give me the itch to rethink it. Hell thinking about it maybe we should just do it. lol lol

Glenn

[spencerc]

Originally Posted by Glenn Kuras

I think that is very well said.



Gotcha or should I say You Betcha

Really I understand what you are saying and agree with a lot of your points. I am sure Ethan is sitting there reading your comments saying "Well if you don't like it then test it yourself". Ethan is a great guy (had dinner with him in NY) but just like anyone else does not like to be called on his hard work. And TRUST me he has put a LOT of hard work into his videos. Which BTW if you do the test and it comes out well I would be more then happy to post it on our website for people to learn. No we don't sell polys as we are talking about in this thread, but then again it might give me the itch to rethink it. Hell thinking about it maybe we should just do it. lol lol

Glenn

Well if I ever get a professionally made QRD then I will definitely do the test and I would really apprecaite you guys posting it on your website!

And your right - Ethan did work very hard and he definitely deserves credit for all the hard work he puts into his videos. I watched them all and they helped me understand the basics of acoustics back when I didn't even have an idea of what acoustics were!

I think GIK should make Poly's....there's a completely open market for them because I don't know of any other acoustic company that produces them!

- Spencer

[jayfrigo]

Originally Posted by spencerc

I think GIK should make Poly's....there's a completely open market for them because I don't know of any other acoustic company that produces them!

- Spencer

And while we're at it, remember, there are poly shapes other than cylindrical. There's another can of worms...

[Glenn Kuras]

Originally Posted by jayfrigo

And while we're at it, remember, there are poly shapes other than cylindrical. There's another can of worms...

[Glenn Kuras]

I think GIK should make Poly's....there's a completely open market for them because I don't know of any other acoustic company that produces them!

crazier things have happened!!

[spencerc]

Originally Posted by jayfrigo

And while we're at it, remember, there are poly shapes other than cylindrical. There's another can of worms...

Haha...The more I learn about acoustics, the more I realize I know almost nothing about it.

[Glenn Kuras]

Originally Posted by spencerc

Haha...The more I learn about acoustics, the more I realize I know almost nothing about it.

Once you stop learning you become dumb.

[johndykstra]

Hello,

A comment here from the ill-informed.

It seems to me, that a test done near a qrd, and a test done near a poly, are going to yeild negligible differences. There needs to be (as I understand it) at least 5% of room coverage with diffusion to make a noticable difference.

If a test is to be done, a whole room needs to be addressed, with absorbtion as well as diffusion. But then what? Some guy just did a test in a 10x23x12' room...great. Means nothing to me.

Having said that, I believe this is a ringing endorsement for polys.

Spec out the cost difference between polys and qrds to cover 5% of your room. (haven't done it myself, but even if you were to do both diy, I'd imagine the cost difference would be significant.)

Would a room (big or small) sound better/different with 5% coverage with qrds vs. 5% coverage of polys...maybe/defineatly.

But whats the return on investment? Is it even measureable once we throw in the caviat that we expect some amount of "different/defineatly"

Problem is, who's going to do such a test? I certainly don't expect Ethan or Glenn, or any manufacturer for that matter, to do it, as they don't produce a commercial poly...so why should they bother. Let's face it, properly treating a room is hard expensive work, and for anyone to come up with two independant acoustic systems just to test them has too much time & money on their hands. And as others have mentioned, I suspect that after an "all poly" test, and an "all qrd" test of the same room; given all of the materials now at hand, the end user is bound to use a combination of the two styles.

My point is, I suppose, that there are many proven methods of diffusion. To the end user: do your research, ask lots of questions, and in the end; do the best with what you can afford...and if that includes the cost of the help of a designer...fantastic.

Speaking of...

I really must tip my hat to the likes of Andre, Ethan, Glenn, Frank, as well as others I may have not run across yet. These guys make a living selling their products and knowledge. Yet come to this community and gladly give people thumbs up on their diy bass trap designs, and make suggestions on how to improve them. There's a thread on this site that people give away tangible pieces of recording equipment to less fortunate slutz, and it receives alot of well deserved praise. These cats do the same on every thread, every day.

[Glenn Kuras]

I really must tip my hat to the likes of Andre, Ethan, Glenn, Frank, as well as others I may have not run across yet. These guys make a living selling their products and knowledge. Yet come to this community and gladly give people thumbs up on their diy bass trap designs, and make suggestions on how to improve them. There's a thread on this site that people give away tangible pieces of recording equipment to less fortunate slutz, and it receives alot of well deserved praise. These cats do the same on every thread, every day.

Thanks man
It is only through education that we can all understand what really matters. Yes we loss a lot of sales do to DYI, but I would rather people treat there room then anything else.

Glenn

[spencerc]

Originally Posted by Glenn Kuras

Thanks man
It is only through education that we can all understand what really matters. Yes we loss a lot of sales do to DYI, but I would rather people treat there room then anything else.

Glenn

And that's what makes you guys first class acts! Your generosity and wealth of knowledge benefits everyone and you should all be given recognition for it!

[andrebrito]

We have had this discussion several times: to make it simpler, a single QRD has better temporal dispersion but worst spatial dispersion than a poly. This has advantages and disadvantages in terms of their applications and places to be applied.

The only papers I know about this matter are from Farina and Cox and are single tested units in lab and NOT in real rooms with diffusers placed in an array. When diffusers are placed in line they start creating lobbing be it QRDs or poly. This can be avoided by using more complex (and more expensive) diffusers

Please check

http://rpginc.com/news/library/tyndall_paper.pdf

[Trev@Circle]

Originally Posted by Glenn Kuras

No we don't sell polys as we are talking about in this thread, but then again it might give me the itch to rethink it. Hell thinking about it maybe we should just do it. lol lol

Glenn

So... rumour has it you came through on this Glenn. So how much and when are you gonna do them in your UK operation?