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monitor placement
Old 12th August 2019
  #31
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Synthpark's Avatar
Quote:
Originally Posted by dinococcus View Post
Put your speakers outside and search the stereo picture.
After Toole, now is the ebu 3276 who are stupid.

This time of push the ignored button.
Speakers outside? What? I dont understand this nonsense. Look for AB stereophony, ORTF and other stuff. Maybe one day you will get it what critical listening is about. Anyway, everything is said ...
Old 12th August 2019
  #32
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Quote:
Originally Posted by dinococcus View Post
Put your speakers outside and search the stereo picture.
After Toole, now is the ebu 3276 who are stupid.

This time of push the ignored button.
+1 Very smart move!

The level of ignorance and arrogance is rather astounding, isn't it? It seems that Andre, Toole, Cox, D'Antonio, Everest, Bert, you, Gervais, and probably even Marshall Long, as well as all the other experts, and now even the EBU, ITU, and likely the AES as well.... all are "novices" and have no idea what we are talking about! He apparently believes that there is only one source of acoustic "truth": himself.

Anyway, to get the discussion back on topic for the OT:

Speaker layout is not that complicated. Start with your mix position on the room center-line at around 1/3 of the room depth (front to back), or really anywhere in the range of about 30% to 45%, with your speakers against the front wall (because it is a small room), the acoustic axis of both speakers at about 120 cm above the floor (about 47 1/4") or maybe a little higher, with the speakers about 30% of the room width away from the side walls (anywhere in the range of about 20% to 35%, actually), and angled in so the both point at a spot about 45 cm (18") behind the mix position. The speaker angle doesn't really matter, as long as it is in the range of around 25° to 35° toe-in.

Call that layout your initial position. Then follow Boggy's procedure. Or just move the speakers further apart/closer together in very small steps, of about an inch or so (around 3cm) for each step, testing with REW at each new location. Look carefully at all of the REW data to find the position that gives you best acoustic response. Then, with the speakers in that position, do the same with the measurement mic: move it in small steps, forward and backward from the initial position, while also rotating the speakers to keep the correct angle, to find the best "new" location. Then repeat the process again with the speakers, moving closer together/further apart to see if there is an even better spot. And one more time with the measurement mic. This procedure will get you to an optimum position fairly fast. It's still a slow, tedious method, yes, but it WILL get you to a good layout.

You can also do it "backwards": with one single speaker set up on a tall stool at the mix position, and moving the mic around to all possible locations wheret he speakers would be. Both methods work. There are other methods too that can be useful. As long as you stick to the process, and move things in small steps, you can optimize rather well.

Then, once you have that "good" setup done, start with the treatment based on the response you are seeing in REW for that location. And once you have most of the treatment in place, repeat the speaker/mic moving process to see if you can further optimize your layout.

Forget about so-called "golden" or "perfect" layout ratios or mystical geometric shapes that don't actually exist: that's all pure garbage. There's no such thing as "one size fits all" in acoustics. There's no one single mathematical layout that works for every single room. All rooms are different, and speakers are different too. The math can lead you to a good starting point, but after that you will need to follow a process of moving things around, that involves real sounds and real acoustic analysis, to optimize. That's the way actual studio designers and acousticians do it. There's no myth, fantasy, or audiophile "magical stuff" involved. Just basic and acoustic theory to get you close, then physical optimization by "making a noise and moving things around".


- Stuart -
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Old 12th August 2019
  #33
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Regarding Genelec's findings; I like akebrakes link in post #23 better, monitor placement -His was quicker and contains 9 pages instead of 11. 9 pages are quicker to read than 11.

(Edit: straaaange, now when I opened up the Genelec links/pdf, both are 9 pages ... )

Last edited by Adhoc; 12th August 2019 at 05:08 PM..
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Old 12th August 2019
  #34
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Quote:
Originally Posted by dinococcus View Post
The steteo imaging is the result of the interaction between the "the reflection" and the speakers by the good dosage.

The EBU 3276 document write - 10 dB if i remember well, not - 20 (like this is promoted here) or - 50 dB.

So what's new?
Exactly!

However, as someone else once said...

Quote:
The "stereo image" is the image information in the recording, the recorded reflections of sound sources,
And here's the rest of us thinking that "stereo image" is the result of correct speaker placement in a good room with good acoustics... How silly of us! If only we would have realized that the stereo image is contained in the actual MONO track from each individual mic, we could have saved ourselves a lot of trouble in all the rooms we design and tune!

- Stuart -
Old 12th August 2019
  #35
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
Exactly!

However, as someone else once said...

And here's the rest of us thinking that "stereo image" is the result of correct speaker placement in a good room with good acoustics... How silly of us! If only we would have realized that the stereo image is contained in the actual MONO track from each individual mic, we could have saved ourselves a lot of trouble in all the rooms we design and tune!

- Stuart -
mono track of each mic? wtf.

Going back to the original statement because this here seems to freak out: if you place the speakers directly near the front wall your stereo image can be seriously compromised. So when you give a person such an advice think of that.

I wanted to give the guy a good advice based on some experience. Other people on this planet seem to have similar experience, outside this forum. But people like you who do not tolerate any other opinion are just poisining this subforum. Just accept that there are different perceptions of what is good practise and bad. Not needed to talk like a group leader in the we-form.
Old 12th August 2019
  #36
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Quote:
if you place the speakers directly near the front wall your stereo image can be seriously compromised.
... which must be why the vast majority of studios place their speakers near to the front wall, or even place them IN the front wall! They do that because they want the stereo imaging messed up. Yup. For sure...

In reality, no: not true. Placing your speakers against the front wall does NOT degrade the stereo image. At least, in a correctly designed and treated studio it does not. Maybe in a very badly designed or poorly implemented room it does, but that has nothing to do with acoustic reality in properly designed and built studios...

I repeat: having speakers against the front wall does not damage stereo imaging.

Quote:
mono track of each mic? wtf.
Yup! That is, indeed, how most mics record: in mono, to one single track. You have a theory about how a U47 placed a few inches in front of a singer's mouth is going to produce a stereo image on that track? How about something simpler, such as an SM57 on a snare? In what way will an SM57 on a snare magically produce stereo information in the track that it lays down? Or maybe your magical effect only happens in the low end, so let's assume we are talking about a plain old Beat-52 inside a kick drum: How exactly is the track form that going to have any hidden stereo imaging?

Truth: a mono mic does not capture a stereo image. The combined signals from several such mics also does not produce a stereo image by itself. To get a stereo image, you need a pair of speakers correctly placed in a room with good treatment. Stereo imaging is a function of the speakers and the room, not of some whimsical hidden information in a single mono track.

Quote:
I wanted to give the guy a good advice based on some experience.
And yet, you failed to do that, and instead gave him a whole bunch of old wives tales and fake silliness that doesn't actually work in real life, and isn't even true anyway. You should probably read Boggy's post to understand why your advice is so wrong...

Quote:
Other people on this planet seem to have similar experience, outside this forum.
I'm sure they do! In fact, some people who live on this planet seem to think that it is flat, not round... and they are wrong too.... There's a lot of folks who live out in fairy land, and want to promote silly ideas about acoustics, speakers, and studios that have no basis in reality. But those of us who actually do this for a living seem to congregate in forums like this, where real acoustics and psycho-acoustics are discussed, by people who actually do know what they are doing. People like Northward, Andre, Jens, Boggy, Bert, DanDan, etc. And where we really do understand the principles and concepts and math and research laid out in texts by world-leading experts, such as Floyd Toole, F. Alton Everest, Cox and D'Antonio, Rod Geravais, Marshall Long, as well as world-renowned organizations like the ITU, EBU, AES, BBC, and NRC among others. You have often stated that you disagree with all of those, and claimed they are wrong, naive, don't know what they are talking about, don't understand acoustics, speakers, studios, control rooms, etc. So I guess you'll have to forgive the rest of us, if we just don't take your claims seriously at all.

To make matters worse, the post you quoted to supposedly support your theory about the front wall, does not actually even mention the front wall, and isn't talking about the front wall at all!

Quote:
Just accept that there are different perceptions of what is good practise and bad.
Nope! Not gonna happen. Because this isn't about opinions: it's about science. Science works DESPITE opinions, not BECAUSE of them. Acoustics is a science, based on repeatable experimentation and research, not imagination and fantasy. If you would have actually read Floyd's book (instead of just pretending that you did), you'd understand how acoustic science is done, and why opinions don't matter. The science of designing and testing speakers is very well documented in that book. He even mentions how he had to abandon some of his own options once he started testing, and even managed to convince a major magazine to abandon their opinions on what makes a speaker sound good, when he showed them the research that proved their opinion wrong. Its worth reading that book. You really should do it. You might be able to abandon some of your own incorrect opinions.

The science of acoustics is very well documented in the books by Toole and the other authors I mentioned: you really should try reading them some day. They all dispel the myths that you continue to promote here.

There's a reason why Northward's rooms always work out great. As do John Sayers's rooms, and Wes Lachot's rooms, and rooms designed by others: they all understand how acoustics REALLY works, and design their rooms accordingly. They don't fall for the fakery and wishful thinking seen all over the Internet in forums that pretend to be useful. They probably don't even waste their time looking at that stuff! Instead, they just design and build world-class studios based on the actual, proven principles and concepts and math of acoustics. Then don't waste their time on ignorant opinions, and instead focus on informed science.

Quote:
Not needed to talk like a group leader in the we-form.
Sorry, but I don't agree with that either! I'm a member of the group "people who design studios for a living", so I will continue to use the first-person when I refer to that specific group of people. If I say "that's the way we do it", it doesn't mean I'm the leader of that group (in fact, it has no leader!). It just means that I'm one of the people from that group, who do it that way. Period.

Anyway, I'll make yet another attempt to get this thread back on track, in the interest of actually helping the OP with his original question:


Quote:
i got an empty room ( front wall height is 2.3m room is 3 meters wide and the lenght is 4.9 meters)
The room is small, but usable. However, it will require a lot of treatment to make it usable. The smaller a room is, the more treatment it will need. In a very small room such as yours, most of the treatment will be bass trapping, and the best place to put that is in the corners of the room. Yes, I realize you are asking mostly about initial speaker placement, not yet about treatment, but they do go together.

Quote:
What is the best placement of monitors and the table..
As I mentioned in my previous post, and as other knowledgeable people have mentioned too, the best location for speakers in a small room is against the front wall. Place them on stands such that the height of the acoustic axis is about 47 1/4" above the floor, o a little higher. The reason for this height is because that's the average ear height of seated people. You can go a bit higher, but not too much.

Also, start with the speakers set away from the side walls at a distance that is about 30% of room width. In your case, that means that the acoustic axis would be about 90cm from the side walls, and the speakers would be about 1.2m apart. That's just the starting position: From there, you can try moving them further apart in small steps, to see if you get an improvement in response Use REW to take measurements of the acoustic response at each step, and compare all of the graphs in REW to find the best location.

For the mix position, start with it at about 185cm from the front wall, on the room center-line, and with the mic at the same height as the speaker axis (47 1/4" or higher). That's also the starting point. From there, move the mic forward and backwards in small steps, and look at the REW data to find the best spot. It will probably be a bit in front of the original location, for most rooms.

Then set up your chair at the location, and place the desk in front of you such that it is in a comfortable working position, and repeat your tests. The desk will have an effect on the response, so you will probably need to move things around just a little to get a better layout.

Quote:
I have read quite a lot, and i understand the best monitor position in this small'ish room is as close to front walls as posible
Exactly. You have read correctly. That is, indeed, the best location in a small room.

Quote:
How close? i will put Acoustic Treatment soon (bass traps in all 4 corners with air gaps, and first reflections and maybe the ceiling)
This is why I mentioned that speaker position and treatment go together. You want the speakers as close as you can get them to the front wall, but front walls often do need some treatment too, so you might have to move the speaker slightly away from the wall to do that. For example, to insert a 4" thick porous absorption panel, if needed. And if you DO move the speakers like that, the you should repeat the "moving around and testing" procedure above, because things will have changed...

Quote:
Regarding 38percent rule, my monitors is about 80-90cm away from the wall, so i have to move my listening position closer...
The 38% "rule" is not really a rule. It's a starting point. And it refers to the location of your head, not the speakers. With your speakers 80 to 90 cm from the front wall, you will have an SBIR dip in the frequency response occurring at about 90 Hz, roughly. That's hard to treat, and will be very noticeable. If you put them against the front wall, the dip will move up to a higher frequency, where it won't be so noticeable to start with, and will be easier to deal with.

So that's the basic concept that all of the knowledgeable people commenting on your thread have been talking about. This is the way studio designers do it, to determine the best position for speakers and listening position. The reason the knowledgeable people are recommending it, is because they know how to do it, and have actually done it... and they now it works!


- Stuart -
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Old 12th August 2019
  #37
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You are totally right, Synth, don't listen to crazy Stu..
The people here have no clue what they are talking about.
I suggest you leave this place and go back to your science-driven real world environment and leave us in our little warped solipsistic universe.
Please?
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Old 12th August 2019
  #38
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For the author of the subject, if your speakers have the port behind, 5 cm are enough between the wall and the speakers.
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Old 12th August 2019
  #39
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
... which must be why the vast majority of studios place their speakers near to the front wall, or even place them IN the front wall! They do that because they want the stereo imaging messed up. Yup. For sure...
So you don't even understand the difference between placing the speakers IN the front wall, which is a kind of perfect aligned wavefront, versus placing them NEAR the front wall and immediately catch a reflection, because the speaker cone is not aligned with the reflective surface, but in front of it? Have you designed any room at all or is it just fake? Nobody spoke about the case of placing them IN.

Quote:
In reality, no: not true. Placing your speakers against the front wall does NOT degrade the stereo image. At least, in a correctly designed and treated studio it does not.
No matter how good the rest of the room is designed, the front wall has its impact. Not hard to understand.

Quote:
That is, indeed, how most mics record: in mono, to one single track. You have a theory about how a U47 placed a few inches in front of a singer's mouth is going to produce a stereo image on that track? How about something simpler, such as an SM57 on a snare? In what way will an SM57 on a snare magically produce stereo information in the track that it lays down? Or maybe your magical effect only happens in the low end, so let's assume we are talking about a plain old Beat-52 inside a kick drum: How exactly is the track form that going to have any hidden stereo imaging?

Truth: a mono mic does not capture a stereo image. The combined signals from several such mics also does not produce a stereo image by itself. To get a stereo image, you need a pair of speakers correctly placed in a room with good treatment. Stereo imaging is a function of the speakers and the room, not of some whimsical hidden information in a single mono track.
Ok, you actually know even less than I thought, but ok, never mind!
Why do you think companies sell stereo mics?

https://www.thomann.de/de/neumann_km184mt_stereoset.htm
https://www.thomann.de/de/akg_c414_xls_stereoset.htm

Because there are stereo mic techniques to record

stereo room track of a drum kit
stereo overheads of a drum kit
guitar in stereo
choir in stereo

and many other sources

https://www.youtube.com/watch?v=bct-5YbKGlU

You never noticed the stereo depth of a well recorded drum kit? How do you want to design a room when you even havent heard of the effect of stereo and do not judge the listening situation with this in mind? That is insane.

And even for mono recorded material: when you take a vocal and run it into a good reverb plugin the vocal gets depth and moves to the back, depending on how the plugin is set. This is all abc knowledge and part of mixing, in the most basic form. You balance between dry, early reflections and reverb tail, plus initial delay. That requires good imaging performance.

cheers
Old 12th August 2019
  #40
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
This is why I mentioned that speaker position and treatment go together. You want the speakers as close as you can get them to the front wall, but front walls often do need some treatment too, so you might have to move the speaker slightly away from the wall to do that. For example, to insert a 4" thick porous absorption panel, if needed. And if you DO move the speakers like that, the you should repeat the "moving around and testing" procedure above, because things will have changed...

The 38% "rule" is not really a rule. It's a starting point. And it refers to the location of your head, not the speakers.
(Ok I skipped all the crazy stuff. If you think I am inclined to ignore science then it is actually the opposite of what I am into, what a joke. There are books on very different levels and sometimes quite different messages, you know?!)

So you actually ARE willing to treat the front wall?
Why didn't you start with this right away? Very good

Yes it is often required, depending on some factors, even speaker selection. There is your magic 4 inch fiber, sadly it fails because it is only 4 inch, but still, the will to use it is there. Next time when you design a studio, test the effect of the stereo imaging with speakers at the front wall or or more distant. Or just come here in my studio and listen.

Quote:
Also, start with the speakers set away from the side walls at a distance that is about 30% of room width. In your case, that means that the acoustic axis would be about 90cm from the side walls, and the speakers would be about 1.2m apart. That's just the starting position: From there, you can try moving them further apart in small steps, to see if you get an improvement in response Use REW to take measurements of the acoustic response at each step, and compare all of the graphs in REW to find the best location.
My room is 5.86m long, is it still a small room? Probably. Speaker separation is 1.75m. 1.2m is way too narrow, unless you are talking about some small PC speakers or Auratones. Below 1.50m is not worth it, the sound stage sounds rather unnatural when using 6 inch to 8 inch speakers.

Here is a good article by the way

https://www.digido.com/portfolio-ite...and-dimension/

Last edited by Synthpark; 12th August 2019 at 10:13 PM..
Old 13th August 2019
  #41
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Quote:
So you don't even understand the difference between placing the speakers IN the front wall, which is a kind of perfect aligned wavefront, versus placing them NEAR the front wall and immediately catch a reflection, because the speaker cone is not aligned with the reflective surface, but in front of it?
You seem to miss the point, yet again (not surprising, actually: it seems to be what you do best.... ). Speakers far from the front wall produce SBIR. The further away they are, the lower the frequency. Conversely, the closer the speaker is to the wall, the higher up the spectrum it goes, and the smaller the effect becomes. The extreme case is flush-mounting (a.k.a.) soffit mounting, with the speaker baffle flush with the wall (yes, it's the baffle that you want flush with the wall. Not the cone: the baffle. I'll but you can't figure out why... ) With the speaker flush mounted, there is no SBIR... at least, not from the front wall. And if you do that entire exercise, starting with the speakers far away and moving them closer, while also adjsuting the mix position and other parameters accordingly, the stereo imaging does get destroyed. Not one little bit. Nothing. SBIR changes, for sure (see above), and there will likely also be differences in the perceived modal response, and perhaps even the real modal response. But the stereo imaging won't change. There's no reason for it to change. And since both speakers will be affected equally, the stereo image will still be the same...

On the other hand, the comments in that post you quoted correctly point out that distance to the SIDE walls can change the stereo imaging. True. If you move the speakers closer to the side walls, then that actually can shift the stereo imaging. But you seem to have misread the post, and assumed that when the author mentioned having the speakers close to "the wall", he meant the front wall. However, when you read it completely, and understand what he's saying, it's clear that he is referring to the side walls, not the front wall. He's also talking about untreated rooms, by the way....

Quote:
Have you designed any room at all or is it just fake?
Way more than I care to remember actually. And been involved directly or indirectly in hundreds. As you could find out for yourself, with a little due diligence...

On the other hand, there's no sign at all that you have ever designed or built a studio, or even that you own one, or work in one...

Quote:
Nobody spoke about the case of placing them IN.
Yes they did: it was me! I spoke about that, to show the extreme case, and how to get rid of front-wall SBIR.


Quote:
No matter how good the rest of the room is designed, the front wall has its impact.
Try to pay attention: Here I am, all along, explaining what a huge effect the front wall has on room acoustics and how to minimize it, and there you are trying to pretend that I'm saying it has no impact at all! The only thing I said about the front wall, is that having your speakers against it does not destroy the stereo image, which is what you claim.

Quote:
Why do you think companies sell stereo mics?
Oh no! Stereo mics! Crossed pairs, and Mid-Side, and all the others! Damnit! Well gosh darn it goodness gracious me, you totally got me there! Welll... not actually, but nice try. It might come as a surprise to you, to learn that stereo mics are actually just two mics next to each other, with two cables that feed two channels on the console.... and thus they are actually just a pair of mono tracks... There is no such thing as you claimed, with each mic and each track somehow encoding stereo information about the room. In reality, each mic only sees the entire room from it's one single unique point of view, and records what it sees. It's not until you send out related tracks to a pair of speakers, that you actually get a stereo image that you can hear. It's the speakers and the room that create the stereo image from the interaction of slightly differing sounds coming from both, not some mystical property of a mono track... You claim to be a mix engineer, but you don't even know where the illusion of stereo hearing comes from? You really though there was something hidden in a mono track? Do you even realize that stereo is just an illusion anyway? It's not true 3D sound field at all. Your brain creates the illusion for you, when you give it enough information, but it's easy to break the illusion... just move your head... The HRTF only works well to give you the illusion of stereo with your head stationary in the sweet spot, but as soon as you move your head far enough in any sense (rotating it to one side, for example), the illusion is broken and all you hear is a pair of speakers. Studio designers know this. Acousticians know this. Mix engineers know this. So how come you don't?

Quote:
How do you want to design a room when you even havent heard of the effect of stereo and do not judge the listening situation with this in mind? That is insane.
Room design for 2.0 rooms starts with the speakers, actually. The room is designed around the speakers to create the illusion of stereo. Without good speakers properly placed in a good room, there is no stereo image. But to get back to the point: putting the speakers against the front wall does not destroy the stereo image.

Quote:
And even for mono recorded material: when you take a vocal and run it into a good reverb plugin the vocal gets depth and moves to the back, depending on how the plugin is set. This is all abc knowledge and part of mixing, in the most basic form. You balance between dry, early reflections and reverb tail, plus initial delay. That requires good imaging performance.
... none of which will happen in a badly designed room, where the speakers are not placed correctly, and/or the mix position is not placed correctly, and/or the room is not treated correctly. You can get a partial illusion of stereo from badly placed speakers in a bad room, yes, but you'll never get the real thing until everything is arranged properly.

Oh, and by the way: if you run a vocal mic through a reverb unit and then listen to one track coming out if it, there's no stereo information in that track... You can't have stereo without two channels, each with a slightly different version of the original sound. That's why stereo mic work, by the way! Because there are TWO mics with TWO signals going to TWO mono tracks, then being produce through TWO speakers, each of which comes from a single mono track. I Do hope you are learning something here.

Quote:
So you actually ARE willing to treat the front wall?
When it needs it, yes. But very often it doesn't need much. It's not the most important wall in the room. Especially if the speakers are flush-mounted. There's another wall that is far, far more important than the front wall. Let's see if you ca guess which one it is...

Quote:
There is your magic 4 inch fiber, sadly it fails because it is only 4 inch,
You are right: it fails below about 30 Hz or so. It's really hard to build a trap from only 4" absorption that works well below 30 Hz. It is possible, but not easy. But for higher frequencies, it does very well. You should take a look at "Master Handbook of Acoustics": Everest has some good graphs in there, showing how well it works. This comes as a surprise to many people, who don't understand acoustics very well, since they seem to think it isn't possible. But it, as shown by both theory and practice.

Quote:
Next time when you design a studio, test the effect of the stereo imaging with speakers at the front wall or or more distant. Or just come here in my studio and listen.
What can I say? Sadly, if you lose your stereo imaging with your speakers against the front wall, then the room must be rather badly designed, or treated. Or laid out.

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My room is 5.86m long, is it still a small room?
Yes. In a room that small, there's not even any true reverberant field. So you are somewhat limited in what you can achieve...

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Speaker separation is 1.75m. 1.2m is way too narrow,
What makes you think I was talking about your room? You should probably go back to post #1 on this thread, and read through it again: You'll see that I have been trying really hard to stay focused on the OP's room, and trying to keep the thread on-track, despite your efforts to run it off the rails into silliness. If you read again what I wrote, very slowly and carefully, you might be able to understand that I never suggested that he should set up and leave his speakers at 1.2m. Do read again... Do try to pay more attention. You might learn stuff.

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Below 1.50m is not worth it, the sound stage sounds rather unnatural when using 6 inch to 8 inch speakers.
Only if you don't know how to set things up correctly, so that it does work, with a good stereo image and sound stage.

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Speaker separation is 1.75m.
So you are saying that, because you have your speakers 175 cm apart, therefore all speakers in all rooms everywhere should also be 175 cm apart? Is that it? You are wanting the OP to set up his speakers 62 cm from the side walls, in a room 3m wide? Is that it?

Sigh!


Quote:
Originally Posted by bert stoltenborg View Post
You are totally right, Synth, don't listen to crazy Stu..
The people here have no clue what they are talking about.
I suggest you leave this place and go back to your science-driven real world environment and leave us in our little warped solipsistic universe.
Please?
Yes yes yes! OK, very true. I retract everything, and agree that none of us know a thing about acoustics, and should be left alone to spew our silly nonsense to each other. Yes very much ! I agree! Synth should just stick to his incredible knowledge of real-world acoustic truth, and go help out all those needy folks on the audiophile forums, so they can understand things better an build better rooms and buy more expensive wire....


- Stuart -
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Old 13th August 2019
  #42
nms
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Quote:
Originally Posted by Synthpark View Post
if you place the speakers directly near the front wall your stereo image can be seriously compromised. So when you give a person such an advice think of that.
There are a few key things to keep in mind here.

1. The frequencies which define the stereo image are primarily above 150hz.

2. Low frequencies radiate from the speaker in an increasingly omnidirectional pattern the lower down you go.

So with that in mind, we know that the first reflection off the front wall is going to be a low frequency bounce.

And what does physics tell us about delaying that powerful LF reflection? By increasing the distance from the front wall you've now carved a hole in your LF response courtesy of phase cancellation from the delayed low frequencies. And it's not just the reflection right in front of you, but also the front wall to ceiling edge, floor edge, and front room corners. You've increased the delay time in the LF reflections from the entire front end of the room. This usually doesn't go well.

Maybe you think placing speakers close to the wall compromises stereo image because you tried it and the LF boost washed out the upper frequencies? If you haven't done a good job of treating the front end of the room, and you don't have any LF EQ adjustment on your speakers to compensate, then it may not work out well. Just don't make the mistake of thinking that's going to apply to someone else's room where circumstances are different.
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Old 13th August 2019
  #43
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Synthpark's Avatar
Quote:
Originally Posted by nms View Post
There are a few key things to keep in mind here.

1. The frequencies which define the stereo image are primarily above 150hz.

2. Low frequencies radiate from the speaker in an increasingly omnidirectional pattern the lower down you go.

So with that in mind, we know that the first reflection off the front wall is going to be a low frequency bounce.
Not really. You can measure the influence of placing an absorber behind the monitors at least up to 500 Hz, I tried so, in several rooms with different speakers (Adam A7, Neumann 310, Dynaudio BM6A, Genelec 8050 to name a few). If it was only up to 150 Hz, no problem, the discussion here wouldn't even exist. I did so using Basotect with a width of 15 cm and about 10-20 cm air gap. cheers
Old 13th August 2019
  #44
nms
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Originally Posted by Synthpark View Post
Not really. You can measure the influence of placing an absorber behind the monitors at least up to 500 Hz. If it was only up to 150 Hz, no problem, the discussion here wouldn't even exist.
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.
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Old 13th August 2019
  #45
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Synthpark's Avatar
Quote:
Originally Posted by nms View Post
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.

By moving the speakers closer to the wall, the problems become higher in frequency and easier to treat.
I have comprehensive rear wall treatment in the mids realized with RPG skyline diffusors (just light enough for the door in the middle). They work very well at 500 Hz. If rear wall was such a problem, I would measure it in the impulse response. So my conclusion, once again, is that the front wall directly, via the first reflection, is responsible for this deviation.

And that reflected wave would hit me first. Otherwise it would loose even more energy travelling to the front wall and back.

Somebody measured the 310s. There isn't that much back attenuation for 180 degrees at 500 Hz as you can see yourself, below 10 dB.

Neumann KH 310 KH310 Left / right woofer positioning - placement inside or outside?
Old 13th August 2019
  #46
nms
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Originally Posted by Synthpark View Post
I have comprehensive rear wall treatment in the mids realized with RPG skyline diffusors.
You have only some diffusors on the rear wall? Of course you're going to have lots of reflected sound returning to the front wall. We have a very different definition of comprehensive.

Anyway.. your speakers aren't flush mounted, so place absorption between them and move on.
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Old 13th August 2019
  #47
Gear Nut
 

wow :D so much information, some of them conflicting, anyway, thank you all for the input, my speakers are on stands, and since i will put bass traps in corners, moving speakers closer to front wall, they will be really close to my bass traps,
Old 13th August 2019
  #48
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Synthpark's Avatar
Quote:
Originally Posted by nms View Post
You have only some diffusors on the rear wall? Of course you're going to have lots of reflected sound returning to the front wall. We have a very different definition of comprehensive.

Anyway.. your speakers aren't flush mounted, so place absorption between them and move on.
500 Hz, even 300-350 Hz, doesn't it follow more or less geometrical acoustics?

There are basstraps in the corners, at the rear wall. The room is 5,86 meters long and 4,66m wide, 3,35m heigh. Even if I put some thick absorbers below the diffusors it doesnt essentially change the frequency reponse, I tried it. I can post an impulse response later. If it did, it would hit the table. I put once a couch in the room and placed it in the back part. Did not change much.

Most problems result from the arrangement directly in the front of the room, around the speakers (windows, ground, table), and the ceiling. I can put down my ceiling absorber just 20 cm down and some notch will move from 150 Hz to 130 Hz.
There are side wall absorbers with a length of 1,80 meters from the front corners into the room, and as heigh as the ceiling, so the sidewalls are treated more comprehensively, if you want to call it that way, 50 cm thick rockwool, an 3,35m x 1,80m area each side. Why this type of arrangement? Because the space in the front at the side walls is basically useless, unless used for acoustic treatment.

So in short: with this type of arrangement I was never able to measure any significant change in the frequency response using additional treatment (by placing 50cm thick rockwool absorbers) at not covered areas at the rear wall. That surprised me. And reverberation is mostly covered with the side wall absorbers, down to 50-60 Hz. Redirection as in other solutions isn't used at all. Not that I wouldn't like to be able to improve room response using rear wall treatment, this would be more convenient than other methods.

cheers

Quote:
Originally Posted by gedna View Post
wow :D so much information, some of them conflicting, anyway, thank you all for the input, my speakers are on stands, and since i will put bass traps in corners, moving speakers closer to front wall, they will be really close to my bass traps,
Hopefully that discussion and dissing wasn't too heavy ^^

Last edited by Synthpark; 13th August 2019 at 04:33 PM..
Old 14th August 2019
  #49
Lives for gear
 

Quote:
Originally Posted by nms View Post
1. The frequencies which define the stereo image are primarily above 150hz.

2. Low frequencies radiate from the speaker in an increasingly omnidirectional pattern the lower down you go.

So with that in mind, we know that the first reflection off the front wall is going to be a low frequency bounce.

And what does physics tell us about delaying that powerful LF reflection? By increasing the distance from the front wall you've now carved a hole in your LF response courtesy of phase cancellation from the delayed low frequencies. And it's not just the reflection right in front of you, but also the front wall to ceiling edge, floor edge, and front room corners. You've increased the delay time in the LF reflections from the entire front end of the room. This usually doesn't go well.

Maybe you think placing speakers close to the wall compromises stereo image because you tried it and the LF boost washed out the upper frequencies? If you haven't done a good job of treating the front end of the room, and you don't have any LF EQ adjustment on your speakers to compensate, then it may not work out well. Just don't make the mistake of thinking that's going to apply to someone else's room where circumstances are different.
Exactly! Well explained. If someone does experience degraded stereo imaging from moving the speakers close to the front wall, that's a sure indicator that the room has serious acoustic issues. It needs proper treatment on the rear wall, and likely the other walls and the ceiling too. There's a problem with the treatment in that room.

Quote:
Originally Posted by Synthpark View Post
Not really. You can measure the influence of placing an absorber behind the monitors at least up to 500 Hz,
That's not coming from the back of the speaker: you are measuring an improvement because you are treating the reflections and decaying field from the rest of the room. At 500 Hz, it's going to be -10dB down at least at the rear of the speaker, and probably more like -15 or -20, depending on the speaker.

Besides, there's not much stereo information at 500 Hz: the HRTF only really gets useful from about 1 kHz upwards. Below 1 kHz, your brain uses mostly ITD to determine direction, and for a pair of speakers equidistant from your ears, there's not much ITD. For higher frequencies, ILD comes into play as well. Your ear and brain do best for directionality in the range 1 kHz to 5 kHz, with some additional stuff up to maybe 15 k or so. But below about 500 Hz, direction detection isn't that great, and certainly below 250 there's very little at all.

In other words, if your stereo imaging improves from front-wall absorption acting around 500 Hz, then that's a sure indicator that there's a problem with treatment elsewhere in the room.


Quote:
Originally Posted by nms View Post
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.
Exactly. +1

Quote:
Originally Posted by Synthpark View Post
I have comprehensive rear wall treatment in the mids realized with RPG skyline diffusors (just light enough for the door in the middle). They work very well at 500 Hz. If rear wall was such a problem, I would measure it in the impulse response.
That confirms what we suspected: your rear wall treatment is insufficient, and incorrect. It's not surprising that you are having imaging problems, if you don't have a fully treated rear wall. Diffusion at 500 Hz is irrelevant to the REAL problem with your room. The real problems will be below 200 Hz. Since those are not being dealt with, once again it's not uprising that you don't get good acoustic response in the room. The back wall is the single most important surface in the room, in pretty much any control room. The other surfaces are important to, to a lesser extent, but the rear wall is the key to getting good response in the room. If all you have there is a diffuser, then that explains the problems you are describing.

It would help if you could do some proper testing with REW, and post your MDAT file here, so we can see what is actually happening there, and help you fix it.

Quote:
So my conclusion, once again, is that the front wall directly, via the first reflection, is responsible for this deviation.
Only because the rest of the room is not treated properly. You are placing the blame in the wrong place: You hear a difference when you put the speakers against the front wall, not because there is a problem with speakers against the front wall, but because the rear wall of the room is not properly treated, and the resulting poor acoustics response of the room is overwhelming your perception of the speakers when they are against the front wall. You are seeing a symptom, and attributing it to the wrong cause. Sort of like assuming that if your car does not steer straight, it must be the steering wheel that is bad, because that's where you feel the problem. But the REAL issue is that one of your front tyres is flat....

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And that reflected wave would hit me first. Otherwise it would loose even more energy travelling to the front wall and back.
Not really. Attenuation of low frequencies over short distances is just a fraction of a decibel. Not even noticeable.
Quote:
You have only some diffusors on the rear wall? Of course you're going to have lots of reflected sound returning to the front wall. We have a very different definition of comprehensive.
+1 So true.

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500 Hz, even 300-350 Hz, doesn't it follow more or less geometrical acoustics?
Not necessarily. It depends on the speaker itself, and also on the room. Don't forget that what you see in the acoustic data published by the manufacturer is take under perfection conditions in a large anechoic chamber. But once you put the speaker in a real room, the actual loading changes dramatically, so the performance is rather different. Read Floyd Toole's excellent book, "Sound Reproduction", and you'll start to see just how big that change can be. Or Kliener and Tichy's book "Acoustics of Small Rooms", to see other examples of how a speaker's response can be so different in a real room, as compared to the ideal measurement in an anechoic chamber.

Quote:
Even if I put some thick absorbers below the diffusors it doesnt essentially change the frequency reponse, I tried it.
You are looking in the wrong place for the wrong reasons! Frequency response is not what you should be looking at for rear wall treatment: time domain response is.

Quote:
I can post an impulse response later.
That would be good, yes. But don't post just the IR: post the actual MDAT file.

Quote:
Most problems result from the arrangement directly in the front of the room, around the speakers (windows, ground, table), and the ceiling.
Likely because the rest of the room isn't treated correctly, especially the rear wall. In a room that has all of the surface treated except the front wall, there won't be major changes from doing things to that front wall. If there are major changes from doing something on the front wall, that indicates that the rest of the room is not treated properly.

Quote:
There are side wall absorbers with a length of 1,80 meters from the front corners into the room, and as heigh as the ceiling, so the sidewalls are treated more comprehensively,
Not necessarily! It's not just the location of the treatment, but also the type and thickness, and the speakers themselves also have an effect... but even if the side walls are well treated without the rear wall being treated heavily, the overall acoustic response won't be good.

Quote:
50 cm thick rockwool,
Your treatment on your first reflection points is 50 CENTIMETERS thick? Nearly 20 INCHES? In a room that is 460 cm wide? So you are taking up one entire meter of room width for side-wall treatment (50cm on each side wall)?

Quote:
I was never able to measure any significant change in the frequency response using additional treatment (by placing 50cm thick rockwool absorbers) at not covered areas at the rear wall. That surprised me
Once again: the changes you want to see will not be very evident in the frequency response. The rear wall is all about time-domain response. There should be some changes in FR, yes, but the changes you are really looking for will be in the time domain. It's a common mistake to concentrate too much on the frequency response graphs for a room: the other graphs are far more informative. Especially ETC.
Quote:
And reverberation is mostly covered with the side wall absorbers,
Not really. That will only help with flutter echo, and width-wise axial modes. It won't do anything for length-wise axials (which are always the biggest issue), nor vertical axials, nor SBIR from the front or rear walls, nor floor bounce, nor ceiling bounce, or the ITDG.

Quote:
mostly covered with the side wall absorbers, down to 50-60 Hz.
With one meter thickness of absorption on your side walls (50 cm on each side) you should be getting a lot lower than that, for your width-related axials, as well as tangentials that involve the side walls, and all obliques too.

Quote:
Not that I wouldn't like to be able to improve room response using rear wall treatment, this would be more convenient than other methods.
Then post your MDAT, and we can help you do that! But probably better do that on your own thread, so we don't hijack the OP's thread any more... Your room is big enough that it can be rather good, if set up and treated properly.

- Stuart -
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Old 14th August 2019
  #50
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Brian M. Boykin's Avatar
Quote:
Originally Posted by Soundman2020 View Post
Exactly!

However, as someone else once said...

And here's the rest of us thinking that "stereo image" is the result of correct speaker placement in a good room with good acoustics... How silly of us! If only we would have realized that the stereo image is contained in the actual MONO track from each individual mic, we could have saved ourselves a lot of trouble in all the rooms we design and tune!

- Stuart -
We need an emoji with an explosion over his head.

Thank you

My nugget of the day.
Old 14th August 2019
  #51
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Synthpark's Avatar
It is not my thread.

Quote:
Your treatment on your first reflection points is 50 CENTIMETERS thick? Nearly 20 INCHES? In a room that is 460 cm wide? So you are taking up one entire meter of room width for side-wall treatment (50cm on each side wall)?
466cm. Yes of course. Because I can treat first reflection points and bass at the same time, since the whole area at the side walls in the front cannot be used to place any instruments or whatever, no need to go for some cheesy internet solution for home studios (corner bass traps / side wall absorbers). So I use 3.35m x 1.80m x 50cm thick "bass traps" up to the ceiling. There is still enough space to arrange a stereo width of 1.80m so where is the problem? From 1.80m up to 5.86m (along front-to-back) I do NOT use those 50cm thick absorbers (except in the corners behind) to make full use of the room (actually there are side wall diffusors in the back part against flutter). Makes no sense to you? Sorry.

The only considerable better solution would have been to use angled side walls and redirect sound, but that was too much effort here, I decided against it. I use "modular" rockwool standard rectangular absorbers, rockwool packed in light foil with certain weight. If I move to another place, I can take all of them with me, as happened before, very practical. Slats at the upper stage come next ... Take care! Viele Grüße!

Last edited by Synthpark; 14th August 2019 at 09:53 PM..
Old 14th August 2019
  #52
Gear Addict
 

Not the most appropriate response I would say, -as Soundmans 2020' post was quite neutral and polite and willing to be helpful. It does contain good info, read it again a couple of times and see the "negative criticism" as advice instead of as antagonism. Could there be some value in it?

If you met in real life, it wouldn't surprise me if there would be much less of harsh words between you two.
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Old 14th August 2019
  #53
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Synthpark's Avatar
Quote:
Originally Posted by Adhoc View Post
Not the most appropriate response I would say, -as Soundmans 2020' post was quite neutral and polite and willing to be helpful. It does contain good info, read it again a couple of times and see the "negative criticism" as advice instead of as antagonism. Could there be some value in it?

If you met in real life, it wouldn't surprise me if there would be much less of harsh words between you two.
If I post a diagram where you see that 500 Hz is not very attenuated the first thing for anyone would normally be to look in the diagram and make a check.

Instead I get a response like

Quote:
Originally Posted by Soundman2020 View Post
That's not coming from the back of the speaker: you are measuring an improvement because you are treating the reflections and decaying field from the rest of the room. At 500 Hz, it's going to be -10dB down at least at the rear of the speaker, and probably more like -15 or -20, depending on the speaker.
The reflection is not even 180 degree, more like 150 or so, or even less. It is not behind the speaker (180 degree). So of what value is that? And the text says clearly that not the whole sidewall is treated. Furthermore, a suggestion like starting from 1.20m upwards to find the best speaker separation is kinda disqualifying, just like in real life. You make a strange statement and people start to doubt. It might sound arrogant to you, I understand that. Argh! Now it is really enough. I need to prepare for a job interview for tomorrow. good night. Internet is harsher than life, I know, but also more revealing.

The graph from the link

And to understand how silly this all is: it is not even only about 500 Hz. Take the fundamental of the female vocal: it will be around 200 Hz or so, the second harmonic can be as low as 400 Hz. Look in the diagram to see that this vocal will be affected.

https://en.wikipedia.org/wiki/Voice_frequency
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Old 14th August 2019
  #54
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Quote:
In short: I don't need any help from trolls like you,
Predictable. Well, I kinda figured you would refuse to post your MDAT here: because you know that when the experts analyze it, we'll find all the things that are wrong with your room, even though you think it is perfect... even though its clear that it isn't very good, from your comments about it! I suppose that's why you don't want to show your data from your room. Nor photos. Nor diagrams. Because you are finally realizing that your room is rather bad, and are ashamed to show it, ... because someone might be able to help you fix it. How sad.... But really, there's no need to be ashamed of a bad room! There's a LOT of people that come here to the forum with bad rooms, and want help to make them better.

Quote:
because you basically know nothing about acoustics
heheheh! If only you know... if only you would do some due diligence... I think you'd be eating your words...

Quote:
No other hobbies than to spend time writing endless postings here?
It's a pretty good hobby, actually! I think it's a good thing when people spend time helping out others like this. I think its sort of noble, in a way. I enjoy it, too. Well, with most people I enjoy it, but some are very annoying and just need to be put in their place. Fortunately, most people are very grateful to get professional help for free, and save lots of money. I'm surprised anybody would think that's somehow a bad thing... Fortunately, there are like-minded people around here, such as Andre, Bert, Jens, Boggy, Northward, DanDan, and a few others, who don't mind donating some of their valuable time to forums like this, to help out people who could probably not really afford to hire acoustic consultants. Yet, here and on other forums they get the same professional advice, for nothing! Why would that be a bad thing?

Quote:
Because I can treat first reflection points and bass at the same time, since the whole area at the side walls in the front cannot be used to place any instruments or whatever, no need to go for cheesy internet solution for home studios (corner Bass Traps / side wall absorbers).
So instead of taking the time to do it right and get good results, you prefer to waste 22% or your room width, and 6 cubic meters of space, killing the room entirely so that is practically dead... but only in the width-wise axis???.... A rather strange way of "treating" a control room. No wonder it sounds so bad in there, and you are getting the poor results that you keep on telling us about... If you would have done it correctly, you'd have a lot more space in the room, and it would sound great too. But if you are content with working in a room that sounds something like the interior of a dead mattress, and you think that it is better than Galaxy Studios, then that's fine! As long as you are happy in your delusion.

Quote:
There is still enough space to arrange a stereo width of 1.80m
I think you are confusing "speaker spread" with "stereo width". It's not the same thing. The sound stage does not only extend from speaker to speaker. Neither does the stereo image. Well, maybe in your room that's the case, but in a well designed room, that's not how it works.

Quote:
The only considerable better solution would have been to use angled side walls and redirect sound
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.

Quote:
but that was too much effort
Well, that explains it then, doesn't it?

But anyway, in the interest of trying to get the thread back on track (yet again!):

Quote:
Originally Posted by gedna View Post
wow :D so much information, some of them conflicting, anyway,
There's actually no conflict here among the people who know what they are doing. All of the experts are in total agreement here: placing your speakers against the front wall will improve the SBIR situation, and will NOT, repeat NOT damage your stereo imaging, or the sound stage. That can only happen in a room that is very badly designed and treated, with no treatment on the rear wall, for example. So it won't happen in your room, because I'm assuming you will treat it correctly.

Quote:
thank you all for the input, my speakers are on stands, and since i will put bass traps in corners, moving speakers closer to front wall, they will be really close to my bass traps,
Right! Do try to get the speakers as close as you can to the front wall. As dinococcus mentioned, even if your speakers are rear ported you can still have them 5cm away from the wall. That's plenty. And as NMS said, placing an absorptive panel between them will help.

Once you get your speakers in place, then you can follow the procedures that people have given you here regarding how to optimize their position, and also the location of the mix position.

Your front wall bass traps are good, but you should really concentrate a lot of your treatment efforts on the rear wall. That's always the most problematic one in any small room. And I'd also suggest that you should think about putting up a "cloud" above the desk.

For the side wall treatment on your first reflection points, you can get good results with absorptive panels about 10cm thick, or 15cm if you can spare the space. But not 50cm! Make panels about 120cm high and 60cm wide, and hang them on the wall at the first reflection points. You do not need to make those floor to ceiling, nor do you need to make them nearly 4m long, and certainly not 50cm thick! That's extreme overkill. If you do that, you'll end up with a very dead room that has no life at all to it, is very fatiguing to work in for long periods, and sounds unnatural and unpleasant. The acoustic response will not be flat: it will be very uneven. So don't make that mistake.

I would also suggest that you after you measure with REW, please do post your MDAT file here, so we can take a look at it, and help you figure out what treatment you might need, and how to get the room sounding as good as it can be. I think I posted this before, but just in case, here's a brief tutorial on How to calibrate and use REW to test and tune your room acoustics


- Stuart -
Old 14th August 2019
  #55
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Synthpark's Avatar
Quote:
Originally Posted by Soundman2020 View Post
Predictable. Well, I kinda figured you would refuse to post your MDAT here: because you know that when the experts analyze it, we'll find all the things that are wrong with your room, even though you think it is perfect...

I think you are confusing "speaker spread" with "stereo width". It's not the same thing. The sound stage does not only extend from speaker to speaker. Neither does the stereo image. Well, maybe in your room that's the case, but in a well designed room, that's not how it works.

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.
You are kind of funny. I asked for for some mdat file from your flattered best-of-the-world measurement a week ago and you didn't show it. Why actually? Now comes your counter-attack!

I have my first laptop here at home, not my other laptop at the studio. And my room is not entirely finished. I can show you some current status, why not, but not this evening.

The sound stage DOES extend from speaker to speaker and NOT further, unless you have serious problems with side wall reflections extending your mix even further, a very bad thing. I had this once in a temporary room, it sucks.

Did I say I angled the side walls? And this "we" makes me sick.

If you have an LCR mix, it must be LCR, right? left speaker, center, right speaker.
I am very happy with my stereo image.

Last edited by Synthpark; 14th August 2019 at 11:34 PM..
Old 15th August 2019
  #56
Lives for gear
Synthpark,

Please post your Mdat files (L, R separate and one L and R Stereo) plus some photos of your room.

Then let the community here take a look and give you a proper evaluation.

Otherwise you just seem like a crazy troll, which is sad.

I would hope that you are indeed interested in getting the best possible results for your CR.
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Old 15th August 2019
  #57
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Quote:
Originally Posted by Synthpark View Post
I asked for for some mdat file from your flattered best-of-the-world measurement a week ago and you didn't show it. Why actually?
Actually, I did explain at the time, but perhaps you forgot, so I'll repeat it here: those graphs are not from my own personal studio, but rather from the studio that I designed, treated, and tweaked for one of my clients. I can only release in public what the client allows me to release, and in fact I think he was rather generous allowing me to release that much (UNSMOOTHED frequency response graphs from 12 Hz up to 500 Hz, showing nearly ruler-flat response). It's the client's data: he paid good money for the design, and the tuning process, so he gets to decide what can be done with his data.

And no, that's not the data from my best studio. Just one of many. There are other studios where I have achieved better results than that. I only chose that set of data because you were arguing that 4" of insulation cannot treat low frequencies, and the graphs from that room proved that isn't so: it can be done. That was just typical of what can be achieved in a well designed, well treated, well tuned studio, when there's a real passion by the client to take his room to the limit, and a good budget for doing so. That's what I commonly get from rooms I do for clients who really want it. If you stay tuned for a few more weeks, I'm working on the final tweaking for a studio for another such client, whom I think I might be able to convince to release some of his data, perhaps even photos (no promises, though). He's a really nice guy, so I'll see what he might allow me to show, or not show.

Quote:
I have my first laptop here at home, not my other laptop at the studio. And my room is not entirely finished. I can show you some current status, why not, but not this evening.
Cool! I look forward to seeing that.

Quote:
The sound stage DOES extend from speaker to speaker and NOT further, unless you have serious problems with side wall reflections extending your mix even further, a very bad thing.
Not at all. If it is done in a carefully controlled manner, then it is possible to extent the sound stage beyond the speakers. Not everyone wants that, of course, and personally I'm not a big fan of doing that in control rooms, but it can be done and some engineers and studio owners do want that. The reason I'm not too keen on doing that is because it's an unnatural extension, and can mislead the mix engineer a bit, since he hears "air" off to the sides that isn't really there. But a good mix engineer can use that to produce better mixes.

And of course for a home theater, audio-phile room, or just plain easy-listening room, there's nothing wrong with that at all! It enhances the listening experience, gives a better sense of "envelopment" and spaciousness, so I'll often do it when I can in that type of room, where precision isn't so necessary.

Quote:
Did I say I angled the side walls?
Yes, you did actually. You said "The only considerable better solution would have been to use angled side walls and redirect sound, ". You claimed it would have been a better solution to do that in your room. I pointed out that angling side walls is not a good idea in a small room. Short memory?

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And this "we" makes me sick.
I can send you a pack of barf bags, if you like! That might help...

I'm not sure what the problem is here: when someone refers to a group of people that he is part of, and is talking about what that group does collectively, then the correct linguist expression is, indeed, "we".

Quote:
If you have an LCR mix, it must be LCR, right? left speaker, center, right speaker.
So you have an LCR console and three speakers in your room, and you do stereo mixes on that? Unusual.... I normally only use LCR consoles in live events and for fixed installations, such as some churches and theaters, where ordinary mono or two channel doesn't do the job well. I'm not aware of too many pro mixing rooms that mix stereo in LCR! I know of quite a few that mix stereo on 5.1 and 7.1 systems, but none that mix in 3.0. Why did you set up your place like that? There can't be much of market for the mixes, I would think...

- Stuart -
Old 15th August 2019
  #58
nms
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Quote:
Originally Posted by Soundman2020 View Post
As dinococcus mentioned, even if your speakers are rear ported you can still have them 5cm away from the wall.
Distance from the wall with rear ported speakers comes up now and then, but in reality I think the speaker angle is sufficient enough to allow the port to function well enough. What's your take on that Stuart?

On a separate note, to give Synthpark a little credit, I definitely do advocate absorption between the speakers on a regular basis. I use it in any room I design which doesn't use flush mounted monitors in a hard front wall (or have a window viewing a live room).
Old 15th August 2019
  #59
Lives for gear
 

Quote:
And to understand how silly this all is: it is not even only about 500 Hz. Take the fundamental of the female vocal: it will be around 200 Hz or so, the second harmonic can be as low as 400 Hz. Look in the diagram to see that this vocal will be affected.
Sorry, but that's wrong again. Your hearing apparatus does not have much ability to accurately determine direction below 500 Hz. All that you showed was the directivity plot of a speaker, which isn't even a polar plot, and bears no relationship at all to the way we hear and determine the direction that sound came from.

Below are some graphs that show how the actual HRTF function works, and the frequencies that are used to provide that sense of direction.

As you can see, there just isn't much precision at all in the low end. Stereo imaging happens in the high mids and highs, not the lows. Yes, a female singer might be able to get down to 200 Hz, but that's not where most of the energy in her voice is: it's much higher up the spectrum.

So, once again, we get back to the issue: if you move your speakers close to the front wall in your room, and you get degraded stereo imaging, then there's something wrong with the way the room is treated, because the front wall does not affect stereo imaging in a normal room, properly treated, as NSM and others have pointed out.

- Stuart -
Attached Thumbnails
monitor placement-hrtf-frequency-graph.jpg   monitor placement-hrtf-frequency-graph-2.jpg  

Last edited by Soundman2020; 15th August 2019 at 04:49 AM.. Reason: Edited to add the graphs that I didn't include the first time...
Old 15th August 2019
  #60
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Quote:
Originally Posted by nms View Post
Distance from the wall with rear ported speakers comes up now and then, but in reality I think the speaker angle is sufficient enough to allow the port to function well enough. What's your take on that Stuart?
I totally agree! People seem to be far to scared of rear ported speakers, or ones with rear passive drivers on them. They don't bite if you put them close to a wall! I'm more concerned about good ventilation than I am about rear ports, for speakers that have heatsinks on the back that get hot. If a rear ported speaker has to go very close to a wall, and there's no ventilation issue, then just plug the port with some type of insulation (even Bert's socks are good for that... ). The same for a rear-ported speaker that is to be soffit mounted (flush mounted). It's usually a good idea to plug the port in those cases. There seems to be reluctance with many home studio builders to do that, but it's a valid and useful technique, and it won't break the speaker.


Quote:
... I definitely do advocate absorption between the speakers on a regular basis. I use it in any room I design which doesn't use flush mounted monitors in a hard front wall (or have a window viewing a live room).
I agree with you here too: for free-standing speakers (not flush mounted / soffit mounted), I usually put some absorption on the front wall, in addition to whatever bass trapping I might have. But that doesn't happen too often: most of the rooms I do are based around RFZ, with flush mounted speakers, so the front wall is mostly reflective.

- Stuart -
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