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monitor placement
Old 24th August 2019
  #121
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Quote:
Hey Stuart, I thought you understand that the stereo image is a product of the direct sound of the speakers in their equilateral triangle that the listener can enjoy. RFZ does not "create" anything.
You seem to be a little confused, or have a very short attention span, because I'm not the one making that claim! YOU are! My comment was pointing out how silly the claim is.

To clarify, you were the one that made the claim that the stereo image is a product of RFZ, not me! Here's exactly what you said, when you dissed nms:

Quote:
It seems that you don't understand the basic principle of the reflection free zone (RFZ) which is primarily responsible for the stereo image,
My comment was in response to that, and it points out that you do NOT need an RFZ design in order to have a stereo image, which is what you claimed. You said that the RFZ "is primarily responsible for the stereo image". That isn't true at all. There are MANY studios and other listening rooms out there that do not use RFZ, and yet have good stereo image.

It seems that you have suddenly come to realize that what I said is true, and now want to backtrack on your original claim!

If that's not the case, then maybe you could explain why you originally said that RFZ is responsible for creating he stereo image, yet now you say that RFZ does not create anything!

Quote:
The RFZ design ensures that the room will not interfere with the direct sound at listening position for mid range and high frequencies. Show me design concepts where this is not done.
Well, let's see now: Abbey Road Studio 2 control room isn't exactly RFZ, yet I've never heard complaints that there's no stereo image. Their Studio 1 control room isn't RFZ either, and ditto. Blackbird C isn't RFZ, very definitely, and nobody seems to be complaining about stereo imaging. I may be wrong here, but as far as I know Philip Newell doesn't build RFZ studios, and people don't seem to be complaining about lack of stereo imaging in his studios. Come to think of it, when I drove my car the other day and listened to some music in there, I got a pretty good stereo image... but I doubt that anybody would call my car an RFZ room!

You might want to do some research and find out what RFZ actually means: it doesn't mean what you think it means...

Quote:
There are only two ways to do it: absorption or redirection of reflections.
Well, no, that isn't true. A proper RFZ can only be created with reflection, not absorption. Now, before you run off the rails into crazy-land again, absorption in, of course, very much necessary in a true RFZ room, but the actual RFZ itself is created with reflection, not absorption.

Quote:
So room-in-room concepts are following redirection, no contradiction to the basic idea to avoid first and maybe second order reflections to the listening position
.Ummmm.... "room in room" has nothing at all to do with control room design philosophy. "Room in room" refers to isolation, not control room design.

And in a true RFZ room, there are no first nor second-order reflections: only direct sound, an ITDG, then a pseudo-diffuse decaying field.

Quote:
For the record: I found it important this morning to correct the flaw in your reasoning.
Ummm.... so now you are flipping your opinion yet again? Going back to saying that RFZ is necessary for creating a stereo image? Because you wrote that in reply this comment: "it is entirely possible to get a good stereo image without having an RFZ". If you are "correcting" that one, then you are going back to your original position again, that it is NOT possible to have a stereo image without RFZ..... Man, you flip and flop more than a fish out of water!


- Stuart -
Old 24th August 2019
  #122
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
You seem to be a little confused, or have a very short attention span, because I'm not the one making that claim! YOU are! My comment was pointing out how silly the claim is.

To clarify, you were the one that made the claim that the stereo image is a product of RFZ, not me! Here's exactly what you said, when you dissed nms:

My comment was in response to that, and it points out that you do NOT need an RFZ design in order to have a stereo image, which is what you claimed. You said that the RFZ "is primarily responsible for the stereo image". That isn't true at all. There are MANY studios and other listening rooms out there that do not use RFZ, and yet have good stereo image.

It seems that you have suddenly come to realize that what I said is true, and now want to backtrack on your original claim!

If that's not the case, then maybe you could explain why you originally said that RFZ is responsible for creating he stereo image, yet now you say that RFZ does not create anything!

Well, let's see now: Abbey Road Studio 2 control room isn't exactly RFZ, yet I've never heard complaints that there's no stereo image. Their Studio 1 control room isn't RFZ either, and ditto. Blackbird C isn't RFZ, very definitely, and nobody seems to be complaining about stereo imaging. I may be wrong here, but as far as I know Philip Newell doesn't build RFZ studios, and people don't seem to be complaining about lack of stereo imaging in his studios. Come to think of it, when I drove my car the other day and listened to some music in there, I got a pretty good stereo image... but I doubt that anybody would call my car an RFZ room!

You might want to do some research and find out what RFZ actually means: it doesn't mean what you think it means...

Well, no, that isn't true. A proper RFZ can only be created with reflection, not absorption. Now, before you run off the rails into crazy-land again, absorption in, of course, very much necessary in a true RFZ room, but the actual RFZ itself is created with reflection, not absorption.

.Ummmm.... "room in room" has nothing at all to do with control room design philosophy. "Room in room" refers to isolation, not control room design.

And in a true RFZ room, there are no first nor second-order reflections: only direct sound, an ITDG, then a pseudo-diffuse decaying field.

Ummm.... so now you are flipping your opinion yet again? Going back to saying that RFZ is necessary for creating a stereo image? Because you wrote that in reply this comment: "it is entirely possible to get a good stereo image without having an RFZ". If you are "correcting" that one, then you are going back to your original position again, that it is NOT possible to have a stereo image without RFZ..... Man, you flip and flop more than a fish out of water!


- Stuart -
Again, nice childish trolling attempt, but harmless.

Never did I say, the stereo image has to be created.

A NONDISTORTED stereo image has to be established by making the early reflections of the room disappear.
The stereo image is created by your speakers.

When you have established this, you get an RFZ, a (R)eflection (F)ree (Z)one.

How you create this, is up to you: absorption, redirection, or diffusion.
Do you wanna see a photo of my backwall?

Now regarding the blackbird studio ...

The blackbird studio C creates an RFZ using diffusion.


Look at their photo. Why do you think there are side wall diffusors?
To create a diffuse sound field, but the RFZ comes for free!
So you seem to confuse even the most basic principles.

cheers

ps: do you believe in quarter lenth rule or is it still "a myth"?
Do you believe in "acoustics of small rooms"?

Interestingly enough

https://www.sweetwater.com/insync/rfz/

https://www.sweetwater.com/insync/ess/

Sweetwater distinguishes between a strategy "RFZ" dedicated to absorption OR redirection
versus diffusion called "ESS" (early sound scattering).

Anyway, using diffusors is to make the reflection to appear as weak as possible.
This blackbird studio is quite unique anyway, given how much space is needed to
get convincing diffusion.
Attached Thumbnails
monitor placement-studio_c_main_image.jpg  

Last edited by Synthpark; 24th August 2019 at 09:28 PM..
Old 24th August 2019
  #123
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Luckly, the audiophiles and music lovers can enjoy a stereo picture without a treated room.
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Old 24th August 2019
  #124
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Synthpark's Avatar
Quote:
Originally Posted by dinococcus View Post
Luckly, the audiophiles and music lovers can enjoy a stereo picture without a treated room.
yeah yeah

https://gikacoustics.co.uk/articles/...oom-acoustics/
Attached Thumbnails
monitor placement-gik-acoustics-242-tritraps-derek-labian-510x340.jpg  
Old 24th August 2019
  #125
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Quote:
Originally Posted by Synthpark View Post
Never did I say, the stereo image has to be created.
So when you said that the RFZ is responsible for the stereo image, that didn't actually mean that you think the RFZ is responsible for the stereo image? Hmmm

And if the RFZ is not responsible for creating the stereo image, then what IS it "responsible" for?

Quote:
A NONDISTORTED stereo image has to be established by making the early reflections of the room disappear.
No it does not: you can still have a stereo image in a room with early reflections, and no distortion at all. Ask any audiophile...

Also, I did mention my car as having a decent stereo image. And y car seems to have a hello of a lot of glass surfaces around head height, which are highly reflective, so my head is definitely surrounded by many, many high intensity reflections... and yet I can hear stereo! How do you explain that?

Also, I sat in a performance hall a few days ago, where they were playing music over a pair of speaker up front, above the stage. It was a highly reflective room, with concrete and glass side walls,... and yet, I could hear the stereo image. How do you explain that?

Ever been to a concert in an old church, with reflective surfaces all around? Notice how you can still hear the stereo image? How do you explain that?

Ever heard a live orchestra in a good concert hall? According to you, there should be no possibility at all of hearing the musicians spread out across the stage in front of you, because of the very high level of early reflections... yet the "stereo image", or perhaps "sound stage" would be more appropriate here, is spectacular, and if you close your eyes you can pretty much point to the location of any instrument as it plays.... How do you explain that? (Yeah, I know, that's not strictly "stereo", but the same principle applies: You are basically claiming that the reflections trash your ability to form the image in your head, which is what the "stereo image" actually is, so it they trash it for just two sound sources, those same reflections should TOTALLY trash it for multiples sound sources.... ) )

Quote:
The stereo image is created by your speakers.
Ahh, so now it's the SPEAKERS that are responsible for the stereo image! Not the RFZ. Not our ears and brains. Hmmm.... OK, if you say so.... But please do make up your mind which of them has the responsibility, because you seem to be flipping and flopping again... So is it the RFZ that is responsible for the stereo image, or is it the speakers? It can't be both, in your black-and-white world.

Quote:
When you have established this, you get an RFZ, a (R)eflection (F)ree (Z)one.
Nope! You just keep right on digging yourself deeper and deeper into that hole, because you refuse to find out what the RFZ concept actually is. I already suggest that you should do that, to avoid embarrassing yourself even more, but you chose to ignore my advice. I repeat: it isn't what you think it is. Your room is not RFZ, neither is Abbey Road Studio 2, nor Blackbird C. None of those are RFZ. Nor are the majority of Philip Newell's rooms, nor the majority of John Sayers rooms. Nor any other room that isn't RFZ.

Go ahead: look it up then come back and admit how wrong you are. RFZ is very specific, and none of those rooms are RFZ.

Quote:
How you create this, is up to you: absorption, redirection, or diffusion.
Try again: you CANNOT create a true RFZ with absorption or diffusion. It can ONLY be done with reflection. Other room concepts can and do use absorption and diffusion successfully, but not with RFZ.

(And once again, to avoid you misinterpreting what I'm saying: Yes, RFZ rooms do use diffusion and absorption, but they do NOT use it to create the RFZ... let's see if you can figure that one out).

Quote:
Do you wanna see a photo of my backwall?
Sure! I'd love to! But your room isn't RFZ. We can see that from the images, and from the REW data you posted. It is far, far from RFZ.

Quote:
Now regarding the blackbird studio ... The blackbird studio C creates an RFZ using diffusion.
No it does not, because it is not an RFZ room! It's that simple. It is ambechoic, not RFZ. An entirely different design concept.

Quote:
Look at their photo. Why do you think there are side wall diffusors?
You do love putting your foot in it, don't you? If that were an RFZ room, there would be no diffusers on most of the walls... The fact that you see diffusers all over, is a dead solid give-way that the room is not RFZ. And the IR for that room is another dead give-away...

Quote:
So you seem to confuse even the most basic principles.
Nice try! And that comes from the guy who said that NMS doesn't understand the principles either, so I'll take it as a huge compliment! If you want to put me in the same category as NMS, then who am I to argue?

Quote:
ps: do you believe in quarter lenth rule or is it still "a myth"?
What "quarter length" rule would that be?

Quote:
Do you believe in "acoustics of small rooms"?
Of course not! Small rooms have no statistical acoustic response, so how could they have any acoustic?.... (Have fun with that one... I like to throw out bones every now and then, for you to chew on. It's fun to watch... )


- Stuart -
Old 24th August 2019
  #126
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
So when you said that the RFZ is responsible for the stereo image, that didn't actually mean that you think the RFZ is responsible for the stereo image? Hmmm

And if the RFZ is not responsible for creating the stereo image, then what IS it "responsible" for?

No it does not: you can still have a stereo image in a room with early reflections, and no distortion at all. Ask any audiophile...

Also, I did mention my car as having a decent stereo image. And y car seems to have a hello of a lot of glass surfaces around head height, which are highly reflective, so my head is definitely surrounded by many, many high intensity reflections... and yet I can hear stereo! How do you explain that?

Also, I sat in a performance hall a few days ago, where they were playing music over a pair of speaker up front, above the stage. It was a highly reflective room, with concrete and glass side walls,... and yet, I could hear the stereo image. How do you explain that?

Ever been to a concert in an old church, with reflective surfaces all around? Notice how you can still hear the stereo image? How do you explain that?

Ever heard a live orchestra in a good concert hall? According to you, there should be no possibility at all of hearing the musicians spread out across the stage in front of you, because of the very high level of early reflections... yet the "stereo image", or perhaps "sound stage" would be more appropriate here, is spectacular, and if you close your eyes you can pretty much point to the location of any instrument as it plays.... How do you explain that? (Yeah, I know, that's not strictly "stereo", but the same principle applies: You are basically claiming that the reflections trash your ability to form the image in your head, which is what the "stereo image" actually is, so it they trash it for just two sound sources, those same reflections should TOTALLY trash it for multiples sound sources.... ) )

Ahh, so now it's the SPEAKERS that are responsible for the stereo image! Not the RFZ. Not our ears and brains. Hmmm.... OK, if you say so.... But please do make up your mind which of them has the responsibility, because you seem to be flipping and flopping again... So is it the RFZ that is responsible for the stereo image, or is it the speakers? It can't be both, in your black-and-white world.

Nope! You just keep right on digging yourself deeper and deeper into that hole, because you refuse to find out what the RFZ concept actually is. I already suggest that you should do that, to avoid embarrassing yourself even more, but you chose to ignore my advice. I repeat: it isn't what you think it is. Your room is not RFZ, neither is Abbey Road Studio 2, nor Blackbird C. None of those are RFZ. Nor are the majority of Philip Newell's rooms, nor the majority of John Sayers rooms. Nor any other room that isn't RFZ.

Go ahead: look it up then come back and admit how wrong you are. RFZ is very specific, and none of those rooms are RFZ.

Try again: you CANNOT create a true RFZ with absorption or diffusion. It can ONLY be done with reflection. Other room concepts can and do use absorption and diffusion successfully, but not with RFZ.

(And once again, to avoid you misinterpreting what I'm saying: Yes, RFZ rooms do use diffusion and absorption, but they do NOT use it to create the RFZ... let's see if you can figure that one out).

Sure! I'd love to! But your room isn't RFZ. We can see that from the images, and from the REW data you posted. It is far, far from RFZ.

No it does not, because it is not an RFZ room! It's that simple. It is ambechoic, not RFZ. An entirely different design concept.

You do love putting your foot in it, don't you? If that were an RFZ room, there would be no diffusers on most of the walls... The fact that you see diffusers all over, is a dead solid give-way that the room is not RFZ. And the IR for that room is another dead give-away...

Nice try! And that comes from the guy who said that NMS doesn't understand the principles either, so I'll take it as a huge compliment! If you want to put me in the same category as NMS, then who am I to argue?

What "quarter length" rule would that be?

Of course not! Small rooms have no statistical acoustic response, so how could they have any acoustic?.... (Have fun with that one... I like to throw out bones every now and then, for you to chew on. It's fun to watch... )


- Stuart -
... hm you talk kinda crap. The stereo image is entirely created by your speakers and needs to be rescued from early room reflections causing it to be distorted, that is to sound different than originally meant, more or less (depending on wall distances of course). This can be achieved in different ways, read here:

http://arqen.com/acoustics-101/reflection-free-zone/

this will hopefully help your confused mind. You see, I can only repeat myself, because anything else is waste of time.

In your car you will hear some sound, it doesn't have to be bad, also hearing reverb gives your brain the abilty to get an idea of sources being far away and near. Still, the sound created by speakers in a an RFZ is totally different. If you would have heard this just once in your life, you would understand.

Once again: you cite "Acoustics of small rooms" by Kleiner/Tichy; but do you believe in quarter length rule or not?
Old 24th August 2019
  #127
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something with attention *****s and so. Please stop it.
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Old 25th August 2019
  #128
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Quote:
Originally Posted by Synthpark View Post
The stereo image is entirely created by your speakers
Actually, no. It's created by your ears and brain. If a tree falls in the forest, and there's nobody there to hear it, did it make any "sound"?

Quote:
and needs to be rescued from early room reflections causing it to be distorted,
You seem to be confused about the technical term "distortion". As I have said many times, early reflections do not produce distortion. Nor do they destroy the stereo image. Anybody can prove this, simply by setting up a pair of speakers in their bathroom, garage or other place with reflective walls: can you still hear in stereo? Yup, you sure can! QED: Reflections do not destroy stereo. Nor do they cause distortion.

Quote:
this can be achieved in different ways, read here:
... and once again you still fail to find out what the RFZ concept is, and instead provide a link to something about reflection free zones...

Quote:
I can only repeat myself, because anything else is waste of time.
Repeating a false statement over and over does not make it true.

Quote:
In your car you will hear some sound, it doesn't have to be bad, also hearing reverb gives your brain the abilty to get an idea of sources being far away and near.
But my car is not an RFZ room, and yet I can hear stereo in there, which is impossible according to you, because "RFZ is responsible for the stereo"...

You also have not explained the performance space situation. You carefully avoided addressing that, because if falsifies your claim.

You also have not explained the old church music conscert situation. You carefully avoided addressing that, because if falsifies your claim.

You also have not explained the concert hall situation. You carefully avoided addressing that, because if falsifies your claim.

You also have not address the simple fact that Abbey Road Studio 2 control room, Blackbird Studio C control room, your own room, practically all of Philip Newell's rooms, many of John Sayers rooms, and many other control rooms around the world are not RFZ rooms, yet they have stereo images. You carefully avoided addressing all of those issues, because they falsify your claim.

And amazingly enough, I just took an old boom-box into my bathroom, which is highly reflective (tiled on all walls and the floor, drywall ceiling), and guess what? I head a stereo image! Incredible! So unless you want to claim that my bathroom is an RFZ room, your claim has been well and truly falsified, and debunked. It is not necessary to have an RFZ room in order to have a stereo image. Because the RFZ is NOT "responsible" for the RFZ in any manner whatsoever.

Quote:
Still, the sound created by speakers in a an RFZ is totally different. If you would have heard this just once in your life, you would understand.
And yet, I design and build RFZ-style control rooms for a living... and other rooms too... While all you have to go on is your own room, which isn't even RFZ!

Quote:
but do you believe in quarter length rule or not?
One more time, since you seem to have a reading comprehension issue: What is this "quarter length rule" to which you refer? I already asked you that the last time you posted your question, and you didn't respond: instead you posted the same question again...

And why would I have to "believe" in something to make it true or not true? Science works DESPITE what you happen to believe (or don't believe), not because of it! So whatever this mysterious "rule" happens to be, it matters not if I "believe" in it (or don't). What matters is if it can be shown to be true, or not true, in the real world.

But whatever this "rule" might be, it does seem to be rather off-topic for the thread, so perhaps you should start a new thread about your religious beliefs and the mythical rules that apparently govern them....

- Stuart -
Old 25th August 2019
  #129
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
Actually, no. It's created by your ears and brain. If a tree falls in the forest, and there's nobody there to hear it, did it make any "sound"?

You seem to be confused about the technical term "distortion". As I have said many times, early reflections do not produce distortion. Nor do they destroy the stereo image. Anybody can prove this, simply by setting up a pair of speakers in their bathroom, garage or other place with reflective walls: can you still hear in stereo? Yup, you sure can! QED: Reflections do not destroy stereo. Nor do they cause distortion.
Pointless to convince the blind that the sky is blue, ok.

Quote:
Originally Posted by Soundman2020 View Post
And amazingly enough, I just took an old boom-box into my bathroom, which is highly reflective (tiled on all walls and the floor, drywall ceiling), and guess what? I head a stereo image! Incredible!
- Stuart -
hehehe
If you listen in supershort distance, direct sound will still largly dominate. To what degree your soundstage is distorted you cannot judge if you never heard the real thing.

Quote:
Originally Posted by Soundman2020 View Post
You also have not explained the concert hall situation. You carefully avoided addressing that, because if falsifies your claim.
Because there is nothing to explain, since it is a different topic. Heard of precedence effect?

https://en.wikipedia.org/wiki/Precedence_effect

Now if you put a stereo mic at this position this is the room impression, the orchestra at this position, what you wanna encode into the recording and reproduce in the listening room. But if the listening room puts his own character onto the recording with its early reflections, you will never get the impression back what you originally heard in the concert hall, so the listening room has to "disappear", but your untreated bathroom will not disappear.

Quote:
Originally Posted by Soundman2020 View Post
And yet, I design and build RFZ-style control rooms for a living...
- Stuart -
... dream on. Have you read the article I showed you? Its not about calling some designed room "RFZ" but establish an RFZ zone. It's all in the article, it's all there. You just have to read it. It's waiting for you. So here once again, this trivial topic just for you:

http://arqen.com/acoustics-101/reflection-free-zone/

Quote:
Early reflections can butcher your soundstage

You want the soundstage in your room to faithfully reproduce the soundscape encoded in your media. This means you want to hear spatial cues coming from your speakers — not from your room!

But early reflections from your room can overpower the spatial cues in your media. They throw off your imaging, destroy your soundstage and mask fine details like the sense of depth and width in a recording. This is called auditory masking.
Do you get it now? No? Continuing to write your untreated bathroom has no effect on stereo image (soundstage?)? You dont know what stereo image is? Then read here: https://en.wikipedia.org/wiki/Stereo_imaging

Look at the diagrams: RFZ by absorption, diffusion, redirection. Nothing mysterious. Nothing worth writing endless postings.

Quote:
One more time, since you seem to have a reading comprehension issue: What is this "quarter length rule" to which you refer? I already asked you that the last time you posted your question, and you didn't respond: instead you posted the same question again...
Short memory?

Master handbook of acoustics: glass fiber absorption

"That's because the "quarter wavelength rule" is a myth!"
Attached Thumbnails
monitor placement-reflection-free-zone-first-reflection-points-treatment-w620.jpg   monitor placement-172472371cf59197b5e6ae48e4d1d525.jpg  

Last edited by Synthpark; 25th August 2019 at 03:07 AM..
Old 25th August 2019
  #130
Lives for gear
 

There is no point in continuing this attempt to educated someone who is blindly, willfully, ignorant, that thinks he knows everything, ore than all the experts here combined, but has proven over and over that they know nothing at all (not even the basics). He doesn't even know enough to realize that he doesn't have a clue. And he refuses to address the very things that prove him wrong, avoiding, evading, and slithering around. "troll" is the right word here.

As a wise man once said: don't cast your pearls before swine.

For the record of those whoa are interested: RFZ is a trademark for a specific design concept, with a very rigid set of specifications. If a room does not meet those specifications, it is not RFZ. Period.

And the signal suffers no distortion from reflections (he doesn't even know what "distortion" means!) And the stereo image is not destroyed by early reflections, nor even harmed at all. It can, in fact, be enhanced by early reflections, as has been pointed out repeatedly. Sigh! (Oh, and the "quarter length" rule is not the same as the "quarter wavelength rule"... which is, in fact, a myth, as pointed out by none other than F. Alton Everest himself, and Andre Vare too. Among others).


I'm out.
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Old 25th August 2019
  #131
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
There is no point in continuing this attempt to educated someone who is blindly, willfully, ignorant, that thinks he knows everything, ore than all the experts here combined, but has proven over and over that they know nothing at all (not even the basics). He doesn't even know enough to realize that he doesn't have a clue. And he refuses to address the very things that prove him wrong, avoiding, evading, and slithering around. "troll" is the right word here.

As a wise man once said: don't cast your pearls before swine.

For the record of those whoa are interested: RFZ is a trademark for a specific design concept, with a very rigid set of specifications. If a room does not meet those specifications, it is not RFZ. Period.

And the signal suffers no distortion from reflections (he doesn't even know what "distortion" means!) And the stereo image is not destroyed by early reflections, nor even harmed at all. It can, in fact, be enhanced by early reflections, as has been pointed out repeatedly. Sigh! (Oh, and the "quarter length" rule is not the same as the "quarter wavelength rule"... which is, in fact, a myth, as pointed out by none other than F. Alton Everest himself, and Andre Vare too. Among others).


I'm out.
Very nice last posting!

Maybe you should read those books first, before referrring to them. And you know what? Its not about only reading, it is actually about understanding what is written, especially the math. Take care!

Everest 5th edition, page 184:

Quote:
Mounting of Absorbents
The method of mounting the test sample on the reverberation chamber floor is intended to mimic the way the material is used in practice. Table 12-1 lists the standard mountings, both in the ASTM form, and in the older ABPMA form.
The mounting method has a major effect on the absorption characteristics of the material. For example, the absorption of porous materials is much greater with an airspace between the material and the wall. The quarter-wavelength (λ/4) rule dictates that a porous absorber for normal incidence must be at least a quarter-wavelength thick at the frequency of interest. For example, for a frequency of 1 kHz, the minimum absorber thickness should be about 3.4 in. Tables of absorption coefficients should always identify the standard mounting or include a description of the way the material was
mounted during the measurements. ...
Kleiner/Tichy
page 133:
Quote:
... that a porous absorber for normal incidence must be at least a quarter-wavelength thick at the frequency of interest. For example, for a frequency of 1 kHz, the minimum absorber thickness should be about 3.4 in. Tables of absorption coefficients should always identify the standard mounting or include a description of the way the material was mounted during the measurements.
page 340:
Quote:
The function of porous sound absorbers is generally poor for frequencies where the distance to the hard back wall is shorter than one-quarter wavelength: for a 0.7 m long wedge, it will be about 70 Hz. The lower cutoff frequency ...
Old 25th August 2019
  #132
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Ignorance knows no bounds....



Like a good troll, since he can no longer respond to the actual subject of the thread, the only recourse is to attempt to distract, avoid, evade, and by any means possible not actually answer the multiple questions, or respond to the multiple challenges.

Anybody else notice that he never, ever attempted to answer even one of the issues that proved him wrong? :=)
Old 25th August 2019
  #133
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
Ignorance knows no bounds....



Like a good troll, since he can no longer respond to the actual subject of the thread, the only recourse is to attempt to distract, avoid, evade, and by any means possible not actually answer the multiple questions, or respond to the multiple challenges.

Anybody else notice that he never, ever attempted to answer even one of the issues that proved him wrong? :=)
The clever reader will understand who is the troll here.
You just described your own behavior very well, avoiding any examination with the RFZ article.

Quote:
Originally Posted by Soundman2020 View Post
...
You seem to be confused about the technical term "distortion". As I have said many times, early reflections do not produce distortion. Nor do they destroy the stereo image. Anybody can prove this, simply by setting up a pair of speakers in their bathroom, garage or other place with reflective walls: can you still hear in stereo? Yup, you sure can! QED: Reflections do not destroy stereo. Nor do they cause distortion.
...

- Stuart -
Quote:
Originally Posted by Soundman2020 View Post
No it does not: you can still have a stereo image in a room with early reflections, and no distortion at all. Ask any audiophile...

- Stuart -
What if someone made a studio without walls?

Quote:
Originally Posted by Soundman2020 View Post
Exactly! Which is why control rooms are designed to attenuate the early reflections as much as possible, so as to not create a false extension of the stereo image (for one reason among several), but pure listening rooms are the opposite, with deliberate attempts to extend the stereo image by using early reflections from the side walls and ceiling to improve the sense of "space" and "envelopment". As you point out, that is NOT desirable for control rooms, which are supposed to just tell the truth, neutrally, but IS desirable for other rooms where listening pleasure is wanted, rather than clinical precision.

- Stuart -
Look at that! WTF???!!! In the other thread you claim the opposite of what you claim here.
You are such a troll its not even funny.

Last edited by Synthpark; 25th August 2019 at 10:41 AM..
Old 25th August 2019
  #134
Gear Maniac
 

For beginners, these kind of threads are golden. Usually in forums when people are going back and forth like this, bickering over small unimportant stuff like semantics or who said what first, threads never seem to end. More and more people join and over time so much information is shared. It's the same with the SBIR thread and several other threads. Goldmines!
Old 25th August 2019
  #135
Lives for gear
 

Quote:
Originally Posted by Synthpark View Post
Look at that! WTF???!!! In the other thread you claim the opposite of what you claim here.
I'm so sorry that you are not capable of reading and discerning two similar threads at the same time. That's a great pity. You'll never manage to learn like this. There is no contradiction there, as every intelligent person can see. They both say the same thing.

And no, I'm not going to get this thread dragged off topic, (which you seem to like doing all over the place). The thread is about monitor placement, not the myth that porous absorption only works at the quarter wavelength mark. If you want to talk about that, start your own thread. The OP was asking about how to place his speakers in his room, and get the best results: I have explained that, several times over, and so have several other expert acousticians and studio designers, but you keep on muddying the waters for him. So I'll continue explaining it as much as is needed, since that's what the OP's thread is about. Thus, I'm not going to comment further on your deep, gross misunderstanding of acoustics, except to correct all of your false statements about monitor placement, every time you make them.

OK, to get the thread back on track: the correct and best placement for speakers in a small room, is tight up against the front wall. Or rather, that's the second best: the best placement is actually to have them flush-mounted in angled sections of the front wall, as is always done in true RFZ rooms, or rooms designed following the RFZ style, or similar styles of rooms, and it can also be done in rooms based on other design concepts. Flush mounting can be done in pretty much any size room (I have done it successfully in rooms as small as 10m2), so it's a good possibility even for home studios. And if you do decide to flush mount, then following the RFZ specs for that and the rest of the room is a good idea... You can't actually achieve those in a small room, of course, but you can aim for that goal and get as close as you can.

If you can't flush-mount (sometimes also called "soffit mounting") that, or don't want to do that for whatever reason, then put the speakers against the front wall.

Placing the speakers against the front wall does not destroy the stereo image, it does not cause distortion (it's actually impossible that it could do so, if you think about it a bit... ), and is the location recommended by the world's leading acousticians, studio designers, and speaker manufacturers for typical speakers and small rooms. In large rooms, it is better to have them far away from the front wall (if they are not flush mounted), but the room has to be very large for that to happen, since you need a distance of about 3m or so from speaker to front wall, plus another couple of meters from speaker to mix position, plus another 8m or so from the mix position to the rear wall, in order for that to be possible. So the room ideally needs to be about 13m long, minimum, then have appropriate width and height as well, if you want to have the speakers away form the walls... That's way beyond the room dimensions that most home studio builders could even dream about! Thus, for home studios, the speakers go against the front wall, on stands (never on the desk, never on the console meter bridge), because that's the spot where you get the best stereo image, the least SBIR artifacts, and in general the most favorable arrangement.

Then, when you have your speakers and mix position set up in the correct locations, you should treat the first reflection points on the side walls and ceiling to minimize early specular reflections as much as possible, because those early reflections can cause the stereo image to seem wider than it should be. That extra width is fine for pleasure listening rooms, such as audiophile rooms, home theaters, and suchlike, but not for a control room. Why? Because a control room should tell you the truth, not coloring or changing the sound in any way. It should be neutral, merely transmitting the sound directly from the speakers to your ears without modifying it at all. If the side walls are allowed to produce early reflections at a level that is too high, or too specular, then the room is not “neutral”: it is adding something to the sound that wasn't supposed to be there, and that can fool your ears and brain (the things that actually create the stereo image....) into thinking that the stereo image and sound stage are wider than they should be, spread over a (mental) distance that is greater than the real distance between the speakers.

Those early reflections are the key to having a "spacious" or "enveloping" sound, that seems to extend a around you, beyond what it should be, and that's nice if you just want to watch a movie and feel like you are part of the action, or if you want to listen to a symphony orchestra and feel like you are right there, in the performance hall, but its not good for a control room, for one simple reason: If the mental image your brain produces of the stereo sound stage is wider than the real sound stage/stereo image, the subconscious tendency is to pan instruments too close together, or too far apart, depending on the person. That mix then sounds either all cramped up when played elsewhere, or it sounds too spread out: it doesn't sound "natural" and normal. Which leads back to the reason WHY control rooms have to be neutral in every sense: so that the mix "translates" to all other playback situations, regardless of acoustics. In a properly designed and executed control room, the mixes will always translate well, naturally and with less effort on the part of the mix engineer than would be needed in a room that is not neutral.

Thus, strong specular early reflections should be suppressed in a control room. In a true RFZ room, there are no early reflections at all, at the mix position: And that’s the source of the famous ITDG, which is a hallmark of RFZ rooms, but is NOT seen in most other design concepts (ambechoic, rooms for example, have no ITDG at all, which is their hallmark... or part of it).

That's not to say that all reflections in the entire room have to be eliminated! Not at all. That isn't even desirable, ever, for a control room or listening room, and is only possible in an anechoic chamber. Your ears and brain do need some "ambience" in order to feel comfortable in the room, and that ambience is caused by having late, non-specular reflections, outside of the Haas time: hence, the importance of the "termination" following the ITDG in true RFZ rooms (and to a lesser extent in some other room concepts). In all good control room concepts, even ambechoic, there's still a "diffuse" sound field that dies away slowly, at a rate that is smooth and even across the entire spectrum, and consistent with the size of the room. Those later reflections (and to a certain extent SOME low-level early non-specular reflections) are all part of the "diffuse" ambient field.

I put "diffuse" in quotes here, because it is actually not possible to have a true diffuse field in a small room, and that's also why I'm using the term "ambient field" here, rather than the more common "reverberant field": because there is no reverberant field in a small room either, for the same reason (“diffuse” and “reverberant” refer to the same thing, basically). That's also why it isn't appropriate to speak of the “RT60 time” for a small room: it does not have one! You can talk about decay times in frequency bands, yes, but that's not RT times. However, people still do use the term, even though it isn't technically correct... so... "whatever". Call it RT60 if you want, but its not correct. “Decay time”, or “decay rate” are more accurate, technically.

So, that's the goal for a control room: neutral, no coloration, no falsely wide or narrow stereo image; just the plain truth. Transmit what comes out of the speakers to the engineer's ears, unchanged. That’s easy to say, but not easy at all to implement! There are many ways of achieving that, with different design concepts, each of which has its pros and cons. RFZ, CID, LEDE, NER, MR, ambechoic, FTB, are just some of them. When newcomers to the world of acoustics look at all that, and see the different specs for each, they think that there must be some type of major contradiction, since different specs can say the exact opposite thing regarding one specific parameter! They assume that at most must be “wrong”, and that there’s only one “right” way that gets perfect results… But that's not really true: The various design concepts are not in conflict when each one is taken as a whole. Only if you compare individual specs from them, out of context: that’s when you can get the wrong picture.

That can be confusing for folks who don't really understand acoustics (but think they do), and insist that there is only one "right" way to build a control room. But as they learn more, they will eventually come to realize that there's no such thing as a "perfect" control room to start with! All rooms are "imperfect" in one or more ways. The various design concepts all attempt to minimize the imperfections based on some priority or other, but in reality each one is just a trade-off: as you improve one thing, that automatically messes up another thing. Therefore, all of these design concepts just represent different balances in the numerous parameters that go into studio design. None is "the best" and none is "the worst". They are just "different", with varying pros and cons. Personally, I prefer the RFZ concept, and most of my rooms are based on that, but I also don't go crazy about the ITDG and the strong termination, which as I mentioned above are key markers for a true RFZ room.... I do things a bit differently…. thus, my rooms are not true RFZ rooms in that sense, and I could not call them that even if they were! Because RFZ is a trade name. Mine are just based on the underlying concept, with variations. (Similar to the way RFZ itself is basically just an extension of LEDE, and fixes many of the issues with LEDE.)

Now, having said all of that, there are still some fundamental truths that do not change between these design concepts. Since they are all aiming for the same goal ("neutral"), they all do have some things in common. Those never change. And since they are all based on producing a clean, clear, accurate stereo image inside the head of the mix engineer, all of these concepts must rely on the same psycho-acoustic effects. Starting at the most basic level with a full understanding of HOW human ears and brains actually produce that stereo image inside our heads! Thus, it is critical to understand things like early reflections, precedence, masking, HRTF, the consequences of variations in the perceived frequency response at the mix position, the effects of masking (both spatial and temporal), the effects of floor bounce, and comb filtering, and SBIR, and a number of other things. In order to design a studio, it is first necessary to understand how the engineer perceives sound, in order to ensure that you are getting the right clues to his ears at the right levels and with the right timing. Then you need to set up the speakers and the room around them to do just that: get the right clues to the ears of the engineer, such that his ears and brain can correctly form the stereo image, which only actually exists inside his head. The studio designer also must ensure that there are no false clues in the sound field that arrives at the mix engineers head, which could throw off his perception of the sound, such as frequency response variations in the high end that are similar to the clues produced in the pinna and that the ear uses to determine direction, or timing variations between the two ears that can also cause problems in identifying both true direction AND true frequency response, nor masking from strong early reflections, nor a whole bunch of other issues.

Some people seem to think that its simple to design a studio, and that they don’t need a studio designer or acoustician: that they can just read a few chapters in a book or two, look at a couple of websites, and they know everything there is to know! But it's not that easy at all. Which is why forums like this are so important, where real studio designers and acousticians are happy to share their expertise, helping out newcomers with pointed comments and advise, since newcomers don’t have the time or inclination to learn everything they need to now (it takes years). Those of us who do help out by replying to questions don't always have the time to explain in detail WHY we said to do one thing and not another in a specific room, but the reverse in a different room (and to be honest, it gets rather boring when you have to give the same explanation for the hundredth time, to the hundredth person with the same problem!), but we do it anyway. It's up the OP to then accept the expert advice that he got for free, or ignore it and go his own way. That's fine. I really don't care if a poster doesn't take my advice, or the advice of another studio designer: the OP is not paying me, the outcome of his studio is not on my head, and my rep won't suffer if he does something different in his place and it doesn't work (or does work!). But I'm happy to offer the advice, and even happier when the poster takes it, implements it, and his studio works out great. That's my only motivation in responding to questions on forums like GS: because I like to help people when I can. Which is why it’s very annoying when some vocal, arrogant, ignorant folks, who actually don’t have a clue about acoustics, but think they do, butt in and mess up the chances that the OP will actually end up with a good studio! It’s frustrating, and requires a response such as this.

In any case, for the OP on this thread: That's what I would suggest: set up your system based on the layout outlined for you above, then treat the room in the ways that small rooms need to be treated, as outlined here and elsewhere, then optimize the room by moving the speaker and mix position slightly, in small increments, to find the best final spot, and perhaps tweak the treatment.

- Stuart -
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Old 26th August 2019
  #136
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Synthpark's Avatar
I have no idea when you have time to drop another 3000 words here. Usually, professionals in this field do not have that much of time or would never invest it and would try to come to the point. You seem to have good "friends" which support you no matter what kind of crap you are writing. Once again: the more you write, the less each sentence has impact.

First of all it is clear from the start that we have a control room here, so the aim of the control room is to reproduce the spectrum and sound stage as true to the recording as possible, any "enhancement" has to be avoided.

Whereas in the first half of the discussion the topic was the front wall which is behind the speaker, where the opinions might deviate, also because the selection of speaker matters, the second half was all of the sudden dedicated to RFZ, where opinions on the effect of ERs on the sound stage should not deviate, unless somebody is lacking the most basic fundamentals. I gave you a link to a good article, where is the thank?

Coming back to the front wall: There are people with a mindset like you who seem to believe in "hard rules", for example to place the speaker "in a small room" always(!) right against the front wall, even if people like me and the author in the SOS article will notice that this often comes with a flat sound stage. If there is a 100-150 Hz dip in the spectrum due to the distance it doesn't mean this cannot be tackled with a well designed front wall absorber.

In general, a discussion with people like you is completely pointless, because you seem not even to understand or appreciate the mechanisms of avoiding early reflections using redirection, absorption, difussion, and will insist to take a room like "blackbird studio C", where ERs are apparently resolved using diffusion, as a "counterprove", although this only show a lack of understanding what can be regarded as RFZ.

Remember the following:

https://www.soundonsound.com/sound-a...near-rear-wall

Quote:
One down side of placing the speaker very close to the back wall is the effect it has on stereo imaging and the perceived depth of the soundstage. In general, the further the speaker is from the back wall, the greater the impression of soundstage depth becomes. So there are lots of interacting aspects of the overall in-room speaker performance that have to be balanced — compromises are inevitable.
But this was not enough. Then you tried very hard to convince that stereo image (=sound stage) can be perceived undistorted even in untreated rooms. You now can try to delete those sentences, but remember that the system stores the date of the last edit.

So after all, despite your claims in this thread, you seem to have learned the lesson noticing in the other thread that control rooms avoid ERs as not to damage the stereo image (congratulations, what a trivial comprehension). Where is the "thank you?". Instead you try to attack again and again. Maybe you feel offended in your delusion to be a great acoustian, whatever ... If discussions stop at this low level, how anyone can ever have a discussion about something really advanced? The only interesting objection came from nms with his front wall absorber. But if the thread starter has a window in the front wall, what then? Goodbye.

So my recommendation to the thread starter: find the best position for your monitors, talking everything into account, do not follow silly rules as to place the speakers always directly at the front wall, because the guy learned this as a "hard rule" ignoring speaker off-axis response and other factors. Go for the best sound.

Last edited by Synthpark; 26th August 2019 at 03:47 PM..
Old 26th August 2019
  #137
Lives for gear
Hey Synthpark,

So this is your current setup where you claim to get excellent soundstage depth ? Seriously dude, that looks like a haphazardly improvised "ghetto" style CR that is still used as a living room by the wife and kids -- something that could be put together in 1-2 weeks with a $500 investment at Home Depot. It literally reeks amateur.

You have been asked to post your complete Mdat files here. But now looking at the photo, I can clearly see why you wont do that ! You'll be ripped a new butthole by the experts here and told to go back to the drawing board. You've still got a lot to learn and a long way to go my friend.
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Old 26th August 2019
  #138
Lives for gear
 
Synthpark's Avatar
Quote:
Originally Posted by sage691 View Post
Hey Synthpark,

So this is your current setup where you claim to get excellent soundstage depth ? Seriously dude, that looks like a haphazardly improvised "ghetto" style CR that is still used as a living room by the wife and kids -- something that could be put together in 1-2 weeks with a $500 investment at Home Depot. It literally reeks amateur.

You have been asked to post your complete Mdat files here. But now looking at the photo, I can clearly see why you wont do that ! You'll be ripped a new butthole by the experts here and told to go back to the drawing board. You've still got a lot to learn and a long way to go my friend.
Lol. Wanna be a snob? If you didn't know: it has to sound, not to look (although looks are about to be finalized as well).
This is the studio before applying slats on the sides, acoustic fabric to hide the sidewall absorbers, not showing the ceiling panel absorbers, not showing the diffusors in the back and left/right corners, corner bass traps. Yes it has excellent soundstage depth, indeed. Not so difficult to get once you get rid of placing speakers at the front wall. Shall I show faked curves like soundman which look almost better than the lab measurement of good speakers, that is measurements without any room at all? Where is the ground reflection in his graphs? Magic, isn't it?! So why should I provide mdat if I could easily fake the FG? It would only be about waterfall.

Did you notice the supplied ETC? Is good enough for an excellent sound stage.

My current investment without speakers and table is somewhere around 4500 Euro I believe. By the way the rockwool sidewall is 50cm thick. You must be a bit inexpirienced. The wood and metall stuff to hold absorbers costs 1000€ alone, it is real wood, not chipboard. There are also corner absorbers between walls and ceiling in three directions. But it is not about MY room here ... there are highly professionals here around, of course! But some are apparently in a completely different league than others.

You can come here and convince yourself (soundstage). I'll happy to post final results for shure, once some tuned absorbers are installed, treating the 1 0 0 mode and vertical mode. I am happy with what I get for the efford I wanna spend. I don't need a 1 million dollar studio to get a good stereo image.

Last edited by Synthpark; 26th August 2019 at 10:07 PM..
Old 26th August 2019
  #139
Lives for gear
Quote:
Originally Posted by Synthpark View Post
Yes it has excellent soundstage depth, indeed. Not so difficult to get once you get rid of placing speakers at the front wall.
What front wall ? It looks like you have two giant, flimsy windows there ! It looks like a living room or bedroom in a suburban house converted into an amateur project studio -- nothing more, nothing less. It looks like what 99.9% of amateur wannabee musicians have the audacity to call a "control room" when it aint even close ! And good luck hearing that "excellent soundstage depth" when the neighbor decides to mow his lawn, and it passes right thru those two giant thin glass windows.

Quote:
My current investment without speakers and table is somewhere around 4500 Euro I believe. By the way the rockwool sidewall is 50cm thick. You must be a bit inexpirienced.
Yep, a typical amateur setup with minimal investment resulting from an amateur level of knowledge. You are spinning your wheels and going nowhere fast. BTW, you cannot even spell "inexperienced" correctly.

Quote:
But it is not about MY room here ... there are highly professionals here around, of course!
Yep, and you obviously have cut out the most important factor in the equation for getting a good mix room -- the designer ! Some of those "professionals" are kind enough to give you free advice, yet you refuse to accept it. And if you truly did your research you would realize that you are not even a white belt, yet you have stepped into the ring with black belts and are getting kicked around and thrown to the floor repeatedly. You are like a sad clown who doesn't even realize that he is a clown.

Quote:
But some are apparently in a completely different league than others.
Some may be 3rd degree black belts, and others 1st degree. Blah, Blah, Blah. All have extensive experience at designing critical listening rooms that meet very high professional standards, learned over a period of many years. But the fact remains that YOU are not even a white belt, yet you are giving advice to others. This is typical of GS these days unfortunately -- I call it the blind leading the blind.

Quote:
I don't need a 1 million dollar studio to get a good stereo image.
True, but it's gonna cost you 10X what you listed in euros to get to the "professional" level IMO -- plus a LOT of hard work DIY once you have the assistance of a real pro and are no longer spinning your wheels and wasting your time. From that photo it looks like you didn't even consider the issue of isolation from the outside world -- so much for that "excellent sound stage" when your neighbor decides to mow his lawn, or when that random car passes by blasting 808s with some big subs in the trunk ! My advice to you would be to tell your ego to take a vacation, admit that you know nothing, hire a designer and go from there. Otherwise you are going to remain stagnating at an amateur level for a long time, like 99.9% of know-it-all wannabees (who know nothing) on the internet.


Last edited by sage691; 27th August 2019 at 12:05 AM..
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Old 27th August 2019
  #140
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Synthpark's Avatar
Quote:
Originally Posted by sage691 View Post
What front wall ? It looks like you have two giant, flimsy windows there ! It looks like a living room or bedroom in a suburban house converted into an amateur project studio -- nothing more, nothing less. It looks like what 99.9% of amateur wannabee musicians have the audacity to call a "control room" when it aint even close ! And good luck hearing that "excellent soundstage depth" when the neighbor decides to mow his lawn, and it passes right thru those two giant thin glass windows.



Yep, a typical amateur setup with minimal investment resulting from an amateur level of knowledge. You are spinning your wheels and going nowhere fast. BTW, you cannot even spell "inexperienced" correctly.



Yep, and you obviously have cut out the most important factor in the equation for getting a good mix room -- the designer ! Some of those "professionals" are kind enough to give you free advice, yet you refuse to accept it. And if you truly did your research you would realize that you are not even a white belt, yet you have stepped into the ring with black belts and are getting kicked around and thrown to the floor repeatedly. You are like a sad clown who doesn't even realize that he is a clown.



Some may be 3rd degree black belts, and others 1st degree. Blah, Blah, Blah. All have extensive experience at designing critical listening rooms that meet very high professional standards, learned over a period of many years. But the fact remains that YOU are not even a white belt, yet you are giving advice to others. This is typical of GS these days unfortunately -- I call it the blind leading the blind.



True, but it's gonna cost you 10X what you listed in euros to get to the "professional" level IMO -- plus a LOT of hard work DIY once you have the assistance of a real pro and are no longer spinning your wheels and wasting your time. From that photo it looks like you didn't even consider the issue of isolation from the outside world -- so much for that "excellent sound stage" when your neighbor decides to mow his lawn, or when that random car passes by blasting 808s with some big subs in the trunk ! My advice to you would be to tell your ego to take a vacation, admit that you know nothing, hire a designer and go from there. Otherwise you are going to remain stagnating at an amateur level for a long time, like 99.9% of know-it-all wannabees (who know nothing) on the internet.

Wow, nice provocation! To try to put the other down as much as possible. This thread sinks even further. Now you have me! Here is an older mdat file, before the table moved in. Table makes some trouble in general, so I am working on it now. This is an intermediate result without treatment of the deepest mode etc. Helmholtz absorbers come later anyway. 1/24, no equing applied to make it look better. Roughly between plusminus 5 dB.

Regarding the window: yes you are right, it is just my own condo. Below is basement, no neighbors around, just above me, but I installed some special suspended ceiling filled with thermarock. Omg I didn't mention the cost to isolate the ceiling, my mistake. But regarding the windows: yes, what do you want to do? There is no permission to close it as a wall and I love the sunlight. The climate is also important. Windows reduce the risk of mold, a common problem with inner insulation. Your mentioned highly pros should also talk and reason like highly pros, which coincides not always with my impression.
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Last edited by Synthpark; 27th August 2019 at 12:40 AM..
Old 27th August 2019
  #141
Lives for gear
May I ask: Is this Mdat of ALL your speakers firing at once -- KH805 sub, 310 Left and 310 Right ?

Not trying to put you down, so I apologize if I came across as rude.

I actually like your choice of monitors. I have heard great things about the KH310s, but have never heard them yet in person. The KH805 subs are amazing though !
Old 27th August 2019
  #142
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IGotWorms's Avatar
 

When trying to get more clarity with speaker placement what I do is turn the speaker toward whatever room Im in at that moment. Makes for more clarity and then everyone knows that I'm a professional at having nice frequencies.
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Old 27th August 2019
  #143
nms
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Quote:
Originally Posted by Synthpark View Post
You seem to have good "friends" which support you no matter what kind of crap you are writing.
Not the case. If you had any awareness for Stuart's work and contributions it wouldn't be as much a mystery as to why he has support and people who understand what he's saying. Good to do your homework before putting this much effort into attacking and disrespecting someone here.

Quote:
Coming back to the front wall: There are people with a mindset like you who seem to believe in "hard rules", for example to place the speaker "in a small room" always(!) right against the front wall, even if people like me and the author in the SOS article will notice that this often comes with a flat sound stage.
I'm sorry you are confused. Both Stuart & myself have been very clear that when placing speakers close to the wall you deal with the remaining front wall interference using absorption. Why are you still bringing this up?

Quote:
you seem not even to understand or appreciate the mechanisms of avoiding early reflections using redirection, absorption, difussion
Can I put a $500 bet on Stuart knowing exponentially more about the above than you do? Come on man.

Quote:
..although this only show a lack of understanding what can be regarded as RFZ.
I'll solve this mystery for you right now. As Stuart is well aware, an RFZ room is a specific room design criteria and is not to be loosely interpreted. This is not the same as simply creating a reflection free zone using any of the methods you just listed. And yes, it can be confusing to people.

Quote:
So after all, despite your claims in this thread, you seem to have learned the lesson noticing in the other thread that control rooms avoid ERs as not to damage the stereo image (congratulations, what a trivial comprehension). Where is the "thank you?". Instead you try to attack again and again. Maybe you feel offended in your delusion to be a great acoustian, whatever...
You're not going to get much support around here if you are this disrespectful and condescending toward someone whose work and contributions we respect, whom we are all well aware has exponentially greater experience than you do with the things being discussed here.

Quote:
The only interesting objection came from nms with his front wall absorber. But if the thread starter has a window in the front wall, what then?
Front wall absorbers work even better with a window behind them. Less mass = less SBIR.

Quote:
So my recommendation to the thread starter: find the best position for your monitors, talking everything into account, do not follow silly rules as to place the speakers always directly at the front wall, because the guy learned this as a "hard rule" ignoring speaker off-axis response and other factors.
I'm willing to bet he learned that from the hundreds of rooms he's designed or consulted on and his understanding of physics and room acoustics.

This thread really didn't need to be 5 pages long. Enough with the petty insults.

Last edited by nms; 27th August 2019 at 09:05 AM..
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Old 27th August 2019
  #144
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Synthpark's Avatar
Quote:
Originally Posted by sage691 View Post
May I ask: Is this Mdat of ALL your speakers firing at once -- KH805 sub, 310 Left and 310 Right ?

Not trying to put you down, so I apologize if I came across as rude.

I actually like your choice of monitors. I have heard great things about the KH310s, but have never heard them yet in person. The KH805 subs are amazing though !
NP. Yes, they are firing at once, mono measurement with sub. The sub compensates certain frequency holes in the spectrum. cheers.
Old 27th August 2019
  #145
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Synthpark's Avatar
Quote:
Originally Posted by nms View Post
I'm sorry you are confused. Both Stuart & myself have been very clear that when placing speakers close to the wall you deal with the remaining front wall interference using absorption. Why are you still bringing this up?
...
I'll solve this mystery for you right now. As Stuart is well aware, an RFZ room is a specific room design criteria and is not to be loosely interpreted. This is not the same as simply creating a reflection free zone using any of the methods you just listed. And yes, it can be confusing to people.
...
To be honest: There is no point in continuing discussions with you and Stuart. If you are such good friends, great for you. This is what you wrote about a week ago:

monitor placement

Quote:
Of course you can measure a difference up to 500hz. You've got plenty of sound reflecting from the back of your room and hitting that front wall. This is why comprehensive rear wall treatment is so important, and where that's lacking you use absorption between the speakers to deal with what remains. The sound radiating out the rear of the speaker is primarily low frequency content though.

By moving the speakers closer to the wall, the problems become higher in frequency and easier to treat.
This is quite wrong, sorry, smaller speakers radiate a fair amount of mid frequencies to the back also. This was proven in this thread referring to data everyone can find and download.

So I have the impression that you might want to make a mystery out of everything? Why don't you or Stuart decribe in one or two sentences what you mean by RFZ room? Also a form of being a little disrespectful to the other. Also, how much intelligence is required to understand the following?

https://proaudioblog.co.uk/home-stud...ker-placement/

So there it is: RFZ zone using redirection of first order reflections and the broad diffusion to avoid second order high level reflections. In the end it is redirection and diffusion. There are also other design approaches. Look how much confusion the term RFZ room design caused: RFZ vs LEDE room, which is best? Now a lot of confusion is caused by statements like this (monitor placement)

Quote:
Angling the side walls is a mistake for a small room. People who have large rooms can afford that luxury, but not in small room. Rather, achieving an RFZ or CID concept is usually done by angling surfaces within the room, at the front of the room, not the sides. It isn't hard to do at all, but it takes some knowledge of acoustics, careful design ability, then some accurate building. I guess that's why you didn't do it, maybe because all three of those are outside of your skill set? But you could hire people to do it for you.
So how to make a RFZ room NOT using the sides? Front of the room? How shall that work? My room is 4.66m in width. Not that small actually. It is nothing personal against you or Stuart. It is just hard to believe stuff if statements like this one are made. Maybe the confusion just arises because I mean surfaces by walls? Not involving any architect, nobody claimed to use real angled walls.

Quote:
And the signal suffers no distortion from reflections (he doesn't even know what "distortion" means!) And the stereo image is not destroyed by early reflections, nor even harmed at all. It can, in fact, be enhanced by early reflections, as has been pointed out repeatedly.
After statements like this it is hard, even impossible for me to believe his claims, because one of the basic drives to establish RFZ is this effect, as pointed out in the article I had linked. So you can claim of 100 room designs, but the huge experience must harmonize with the statements. Claiming the opposite in another thread makes is not easier for me. When looking at the uneven off-axis response of typical speakers it is very difficult to understand how the stereo image for a control room(!) should be enhanced even beyond speakers consistently across the spectrum.

Looking at a listening room here: monitor placement
it is difficult to understand why GIK would show a listening room with simple absorbers at the sides to avoid any coloration and "enhancement" of the stereo image and why the speakers have a fair amount of distance to the front wall, looks like a sacrilege when listening to your recommendations.

The best thing would be if Stuart has a clear link in his signature that one could enjoy his room designs. By now it is simply too difficult to believe in measurements which show a ruler flat frequency response looking almost better than the lab measurement of the speaker made by the manufacturer, without any sign of floor bounce, but later in another thread stating that the floor bounce cannot be avoided and "the brain can deal with it".

I have a bad memory, but somehow it works quite well in remembering what each person claimed, even if weeks or months have passed. I understand that this ability can easily cause antipathy. In general, I want to apologize if my bad English leads to hard formaled phrases here and there, it is just the language barriere.

I coming from academics and work in the electronic industry for a long time. I can fairly estimate the level of experience claimed by people even as a non-expert, if certain contradictions exist. On the other hand, sometimes some professional will follow a certain method for years, although that method is not even the best or the only one, a very common phenomenon. Or he believes in wrong physics or wrong cause of some effect, but he is still able to do good work, sometimes with a fair amount of improvisation, because it simply doesn't matter. And acoustics is a very complex field, nobody has really seen how sound propagates.

Believe me I know what total harmonic distortion (THD) means and you can be sure that there is no problem within the context of acoustics to speak of "distortion" when referring to something like stereo image, although it is linear convolution with the room response.

But anyway: it is not required to be right in certain questions in order to make room designs and achieve good results. It seems that people are coming from a very different background in this field. Different people believe in different things, it's all good. Most customers will be happy anyway. So before hitting page six, I am definetly out now.

So if you and Stuart acquire customers through this forum it was certainly not my intention to do any damage to your reputation or whatever, I am merely interested in the best practises and acoustic "truths". In fact, it all started by after I posted my impression on the subject and my recommendation, see page one, not having in mind to start an endless discussion. *Peace*
Attached Thumbnails
monitor placement-rfz-control-room-large.jpg  

Last edited by Synthpark; 27th August 2019 at 12:18 PM..
Old 27th August 2019
  #146
Lives for gear
 

Quote:
Originally Posted by sage691 View Post
May I ask: Is this Mdat of ALL your speakers firing at once -- KH805 sub, 310 Left and 310 Right ?

Not trying to put you down, so I apologize if I came across as rude.

I actually like your choice of monitors. I have heard great things about the KH310s, but have never heard them yet in person. The KH805 subs are amazing though !
problem is that great gear in the hands of inexperienced folks (and even more so of ignorants) doesn't help much!

the sub in the pic is clearly not well positioned, besides the many other flaws already addressed by other posters; don't even need to see any measurements, it's pretty obvious just from the pic - wish the pic would have been posted way earlier, could have spared a lot of troubles...

there should be a newbie/hobbyist/diy sub-forum in every forum!
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Old 27th August 2019
  #147
Lives for gear
Neumann produce a manual where all is explain.

it's true 35 years and 5000 concerts, one every two days, you are a superman.

your class contempt has nothing to do here
Old 27th August 2019
  #148
Lives for gear
 
Synthpark's Avatar
Quote:
Originally Posted by deedeeyeah View Post
problem is that great gear in the hands of inexperienced folks (and even more so of ignorants) doesn't help much!

the sub in the pic is clearly not well positioned, besides the many other flaws already addressed by other posters; don't even need to see any measurements, it's pretty obvious just from the pic - wish the pic would have been posted way earlier, could have spared a lot of troubles...

there should be a newbie/hobbyist/diy sub-forum in every forum!
hm what do you know about me?
Was your bull**** post really necessary here?

It's the best position in this room. No, a slightly off-middle position is not better. No, the sub placed at the front wall is definetly also not better. It is all on purpose.

Last edited by Synthpark; 29th August 2019 at 03:50 AM..
Old 27th August 2019
  #149
nms
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Quote:
Originally Posted by Synthpark View Post
To be honest: There is no point in continuing discussions with you and Stuart. If you are such good friends, great for you. This is what you wrote about a week ago:

Quote:
Originally Posted by nms
The sound radiating out the rear of the speaker is primarily low frequency content though. By moving the speakers closer to the wall, the problems become higher in frequency and easier to treat.
This is quite wrong, sorry, smaller speakers radiate a fair amount of mid frequencies to the back also.
I think now is an excellent time for you to look up the definition of "primarily". Note that primarily doesn't mean "only".
The higher the frequency, the more directional it is.

Quote:
how much intelligence is required to understand the following?

https://proaudioblog.co.uk/home-stud...ker-placement/
Good question. I feel like it's been explained a few too many times here. The article gets it right though: "In a small room, after having considered all the above details, the distance from the speakers to the back wall will most often be quite small, and some people can find that concerning; after all, the wall will indeed create cancellations and dips in the frequency response. However, the closer the speakers are to the back wall, the higher the frequency of the cancellations, and the easier it is to treat it with acoustic absorbers. Many manufacturers recommend placing the speakers as close to the wall as possible (whilst allowing a few centimetres for the bass port) and then adding strong acoustic treatment to dampen the back wall reflections."

Quote:
So there it is: RFZ zone using redirection of first order reflections and the broad diffusion to avoid second order high level reflections. In the end it is redirection and diffusion. There are also other design approaches. Look how much confusion the term RFZ room design caused: RFZ vs LEDE room, which is best?
Yes, it gets confusing, and if I'm being honest.. it's best for those with more experience to make an effort to discern whether or not someone is referring to an RFZ room (room design criteria invented by Peter D'Antonio with specific reqs) or simply a reflection free zone. Conversations go better when people are making a genuine effort to understand each other.

The RFZ room design criteria uses splayed walls and ceiling to redirect reflections into the rear wall diffusers, just like the image you posted above.

Quote:
Looking at a listening room here: monitor placement
it is difficult to understand why GIK would show a listening room with simple absorbers at the sides to avoid any coloration and "enhancement" of the stereo image and why the speakers have a fair amount of distance to the front wall, looks like a sacrilege when listening to your recommendations.
Not the case. We are all in agreement about the benefit of using thick absorption on side walls. And the image you refer to is an audiophile's living room with a big window. You're not likely to convince him to block that window with front wall absorption. No one is making mix decisions in that room though, so that's quite alright. Residential listening rooms have their compromises

Quote:
I coming from academics and work in the electronic industry for a long time. I can fairly estimate the level of experience claimed by people even as a non-expert, if certain contradictions exist.
Sometimes things seem to contradict but it's a result of key differences involved.. or just plain old miscommunication, which tends to happen more when people become annoyed and are making less an effort to genuinely understand each other. Typical silly internet stuff.

Quote:
I am merely interested in the best practises and acoustic "truths". In fact, it all started by after I posted my impression on the subject and my recommendation, see page one, not having in mind to start an endless discussion. *Peace*
I believe your motivation comes from a good place, and like I said before I know well how someone can come to believe things based on what they've read and the limitation of their own experience. I would just suggest to try and be a bit more respectful and not get ahead of yourself. It makes for less stress & wasted time, more intelligent convo, and often you don't know who you're talking to. lol, I'll never forget the time I argued with Alexey Lukin about sample rate conversion before I knew who he was

As for Stuart, he holds down the fort over at http://www.johnlsayers.com/phpBB2/index.php

Anyway, back to projects and another break from the time vortex that is GS!

Cheers man
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Old 29th August 2019
  #150
Here for the gear
 

Image shift ( depends on source material)

Next problem : I have a small opening ( alcove 4 feet by 8 high, 1 foot deep) a touch behind and adjacent to left speaker. The other side is straight ( dry wall)

I seem to notice ( at times, depending on source material) slight image shift to the LEFT!
What possibilities are there to “ close” and or make this opening acoustically close or even to the right side?
I have ceiling bass traps on both corners and first reflection points on side walls are covered,
Thanks
Howard
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