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Monitors placement/room acoustic
Old 4th September 2018
  #1
Here for the gear
 

Monitors placement/room acoustic

Hi everyone
i need help on monitors placement
in monitors manual it says they must be at least 1.5 meter away from walls or corners which is impossible in my place

so is any method should i follow to find the right monitors' distances from rear and side walls?



i read that the distance which monitors have from rear wall should be the same with the distance from listener and distance between monitors like this
http://www.cardas.com/images/room_setup_diagram_c.jpg

so is this the right way?
these are my place dimensions
https://www.gearslutz.com/board/atta...9&d=1536070635

https://www.gearslutz.com/board/atta...1&d=1536070680

exept monitors placement, is this room's shape and its dimensions good for building my studio?
should i close the open side or it helps for reverberation time?
thanks
Attached Thumbnails
Monitors placement/room acoustic-katopsi.jpg   Monitors placement/room acoustic-katopsi2.jpg  
Old 4th September 2018
  #2
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Jens Eklund's Avatar
Regardless of what your manual states:

Maserati speaker placement
Old 4th September 2018
  #3
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
Regardless of what your manual states:

Maserati speaker placement
Do you have a preference for speaker / triangle / listener setup if the room response would be comparable.

A, B or C?


In a web search you find recommendations for every of the shown setups.

Would be cool to hear your opinion as a professional for room acoustics.

Thanks

Tom
Attached Thumbnails
Monitors placement/room acoustic-.jpg   Monitors placement/room acoustic-b.jpg   Monitors placement/room acoustic-c.jpg  
Old 4th September 2018
  #4
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Jens Eklund's Avatar
Inbetween A and C.
Old 4th September 2018
  #5
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
Inbetween A and C.
I like that answer :-)

It is the opposite of that what your expert colleagues here say:

Rod Gervais: 40 cm inside (Picture B)

jhbrandt: 15 - 18 cm inside (like Picture B)


Northward: 30 cm inside (like Picture B)


I guess not active here in the forum:


Wes Lachot: 45 cm inside (like Picture B)


Carl Tatz: 30 cm inside (like Picture B)


I did some web search about the topic and took some notes.

Please do not get this one wrong. I do not want to question your opinion. It is just interesting that you choose the other pictures.

Would you like to explain where you see the advantage of A or C?

Tom
Old 5th September 2018
  #6
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Jens Eklund's Avatar
I wouldn’t call it “opposite”, here´s what I normally do:

Monitors placement/room acoustic-listening-triangle.png

As you can see, the head is within the triangle just so that the sides of the triangle are in line with the average person’s ears, but still maintaining the standard equilateral triangle setup. The 5 deg offset of the on-axis (because of the 25 degree angle of the front wall and thus speakers) is due to a number of reasons:

1. The front wall consumes less space.

2. The rear wall diffuser sees more on-axis sound field than if speaker angled more towards sweet spot.

3. I personally feel that the soundstage “opens up” if speakers are “shooting past” the sweet spot.

4. Persons further back in the room will hear more on-axis sound (not that I´m that concerned about possible listening positions other than sweet spot).

This naturally assumes that the 5 deg off-axis (in the horizontal plane) direct sound measures flat. There’s often very little difference between on-axis and 5 deg off-axis in the horizontal plane, but even it there is, you can correct the direct sound to measure ruler flat by DSP.
Attached Thumbnails
Monitors placement/room acoustic-listening-triangle.png  
Old 5th September 2018
  #7
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
I wouldn’t call it “opposite”, here´s what I normally do:


As you can see, the head is within the triangle just so that the sides of the triangle are in line with the average person’s ears, but still maintaining the standard equilateral triangle setup. The 5 deg offset of the on-axis (because of the 25 degree angle of the front wall and thus speakers) is due to a number of reasons:

1. The front wall consumes less space.

2. The rear wall diffuser sees more on-axis sound field than if speaker angled more towards sweet spot.

3. I personally feel that the soundstage “opens up” if speakers are “shooting past” the sweet spot.

4. Persons further back in the room will hear more on-axis sound (not that I´m that concerned about possible listening positions other than sweet spot).

This naturally assumes that the 5 deg off-axis (in the horizontal plane) direct sound measures flat. There’s often very little difference between on-axis and 5 deg off-axis in the horizontal plane, but even it there is, you can correct the direct sound to measure ruler flat by DSP.


Jens,

Well thought out. You get closer with the speakers to the front wall and do not loose that much space or you can cover a wider area with thicker treatment, whatever is required. You open the stereo image -> like sitting further inside. And you stick almost to what every speaker company prints in their manuals.

This setup is very good.

You should not hesitate to link to it very often.

cheers
Old 5th September 2018
  #8
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Jens Eklund's Avatar
Quote:
Originally Posted by Lebowski666 View Post
Jens,

Well thought out. You get closer with the speakers to the front wall and do not loose that much space or you can cover a wider area with thicker treatment, whatever is required. You open the stereo image -> like sitting further inside. And you stick almost to what every speaker company prints in their manuals.

This setup is very good.

You should not hesitate to link to it very often.

cheers
Thank you.

Yes I have thought about these things a bit ...
Old 5th September 2018
  #9
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
Thank you.

Yes I have thought about these things a bit ...

Most speakers don´t even fall out of the -3 db range in the horizontal dispersion at 5 degree off axis.

In my home studio i have those coaxial Genelec speakers. They are also at 25 degree angle relative to the front wall. Sounded much better to me. Measured equally good as 30 but sound more coherent to me.
I creates a wider sweet spot. I get a more consistent sound by moving around while working.

In the studio i work they have some ATC´s at 30 degree. You can also work with this setup. Our brain can get used to many situations.

In real live mix engineers don´t have their ears at a fixed point in the room.

It is important to make sure that speakers are placed in a way that they measure good in a certain area. Like a circle.

Most of the people are listening to music nowadays with headphones or even just smartphones.

The classic home stereo camp is very small today.

Even though i sit in a setup like the one you posted i sit also closer to the speakers. I have not measured but i am sure that my desk starts at a point that is around 450 mm in front of the tip.

I hear there more left right separation and also the center image is more in your face. Reminds me of the sound when i listen to music in a car. And maybe also a bit more headphone like.
But there is no high frequency roll off at the working position. Genelecs have their own sound and if you like them you like also the brightness they provide.
But i often roll back with my chair while mixing - or while setting levels and get much closer to the classic equilateral position. So i hear if the mix works also in a more ordinary home stereo situation.

I am also sure that everybody´s brain expects left and right from a certain location. Also the loudness of the center has to fit the own habits. I know where i want to hear a guitar when it is panned hard left or right.


So back to roulhs:

I just want to say that even if there are many (and sometimes really good) recommendations in manuals and forums, at the end of the day you and your ears will decide where you want your speakers.

For room treatment and setup:

Learn how to use REW and how to interpret the results.
Learn which methods work to get rid of the problems the measurements show you.

Learn how to get rid of modal ringing. Learn how to find a good speaker position in your room, learn how to get rid of nasty reflections, learn which methods are there to not make your room damped to dead.

If you decide to treat a room by yourself then you must first learn how this is basically done.

It is fantastic to work in a treated room. But do not expect to fix your room in a week.

I tuned two rooms myself. And it was a long road till it worked. To be exact in the first room it was a mess of trail and error.

This is a few years back but i remember that it was more important to me to keep the cost low than anything else.
I read more in forums instead of measuring around and learn.

In the end i learned how to read the graphs in REW and got a feeling how the things are going in my room. We are talking about a time window of a year here. This was the first room i worked in.

The second room was way less a problem. I learned from all the mistakes i made the first time. And it was done in a few weeks.

Room acoustics is not just a funny game. Prepare yourself and learn first and take your time to try out.


cheers

Edit:
If you want to search here at GS. You will soon find the professionals. For a basic home studio in my opinion (and this is very personal) the concept that boggy shares is a more easy one. All other concepts require much more knowledge. I do not want to say that it is better than the others - but it is good for small rooms and compared to the other concepts it will keep the cost somewhat more down.
I mean the simplified version that he shared here few years ago and not the actual with all the air transparent diffusion. Basically you put as much glasswool in you room as possible and attach afterwards wood slats to the fabric covered glass wool walls using the MLS sequence he shared here.
In small rooms it is hard to get a good reverb time. Often the rooms are too short for diffusion and often it is needed to make the rooms even smaller with applying of a lot of thick glass wool, so you would get to close to the diffuse sound field.
Oh and the concept that adrumdrum shared here is also good and easy for DIY. Your room has a good length - so some back wall diffusion can be an option.
If you want to learn about pressure based absorption search for posts from Jens Eklund. You can also find much information about diffusion.
There are more names you will often find. They all shared a lot of good information. But it takes time to sort it for you.
In my first room i endet up with somewhat that was close to the simplified version of the concept of boggy cause the room was too short for diffusion. What i did not like was the MLS slats at the reflection points. I went dry at these spots.
Ah and i would stay away from the panel here and there thing. In the end you will have most likely all walls completely covered with panels.
Old 5th September 2018
  #10
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Jens Eklund's Avatar
In a room that is too small for diffusers, this is what I normally do:

Monitors placement/room acoustic-resonator-stockholm-ab-1.jpg
Monitors placement/room acoustic-resonator-stockholm-ab-2.jpg

Not very different to what you describe. Deep porous absorption on early reflection areas and variable width/gap slotted panel on other areas.
Attached Thumbnails
Monitors placement/room acoustic-resonator-stockholm-ab-1.jpg   Monitors placement/room acoustic-resonator-stockholm-ab-2.jpg  
Old 6th September 2018
  #11
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
In a room that is too small for diffusers, this is what I normally do:


Not very different to what you describe. Deep porous absorption on early reflection areas and variable width/gap slotted panel on other areas.

I hear it sounding great in that room by just looking at the pictures.

side walls do not look parallel too each other and are at a good distance. Open area seems to be way less than 15 - 20 % in this case. I would fear flutter in a parallel situation.

For a moment i have to agree with a part of what Tomtom posted above. You seem to like it to go the other way round. There is a lot of talk about vertical vs horizontal slatting in rooms to find here. most agree on vertical at side walls + horizontal at ceiling.

I guess you are not caring about additional stereo spread that vertical slats can / should / whatever provide. Not everybody likes the widening.

I guess your target with this kind of slatting is to address the low reverb time after needed rockwool treatment. And I am pretty sure that you are addressing a mode with the slots. gaining some helmholtz response. please correct me if i think wrong.

By just looking at the back wall i assume a 120 cm height of the absorbtive part of the back wall. 60 cm up and down from ear height i guess.


The side walls can add a lot to a better reverb time. Would the ceiling also work if not angled? flutter?
have you done this on a straight ceiling.


I would fear some reflections from the back wall at a first look by rolling back to get the home stereo response, but it can be that it is impossible because of the angled walls you did in the room. This is what i meant with my post. It is art to make it work. one can not copy this by just looking at those nice pics. a lot of calculation and experience is hidden behind what the first look shows.


cheers
Old 6th September 2018
  #12
Here for the gear
 

first of all thanks for your replies
so, i did the placement by following this here

Room Setup: Rectangular Room
Speaker to side wall: RW x .276
Speaker to rear wall: RW x .447
Speaker to opposite side wall: RW x .724
Speaker to speaker: RW x .447

i upload an image below
https://www.gearslutz.com/board/atta...9&d=1536248702

about REW i learned a lot(by reading threads and watcing videos), but i stuck the whole day trying to take measurements(i am newbie at this)
specifically i had problems with calibration,mic test so i couldnt even continue to measurements
so i decide to avoid this(even its important) and continue with acoustic treatment

at first i think to start with acoustic panels(which i decide to build my own by reading threads,articles etc)
one problem is the thickness of panels
if i had measurement results by REW maybe i could decide the thicknesss and how many do i need.correct me if i m wrong
the placement method which i found ,is to use a mirror(to side and rare walls) to find the placement spots

so i believe a good start is to build 7 acoustic panels
2+2 on the side walls
2 on the wall behind me
1 on the ceiling
behind monitors i cant place panels cause of sliding glass door
is there any solution for this?

about basstraps
i have some questions
i read that their placement is at corners
the problem here is with some corners in my place
some are double and i dont know where to place the basstraps
also the wall behind me has only 1 corner cause the room's shape
i upload an image below
https://www.gearslutz.com/board/atta...0&d=1536248705
so how to deal with that?

THANKS !!!
Attached Thumbnails
Monitors placement/room acoustic-monitors-placement.jpg   Monitors placement/room acoustic-monitors-placement2.jpg  
Old 7th September 2018
  #13
Here for the gear
 

any advice ?
thx
Old 7th September 2018
  #14
Gear Head
 

Quote:
Originally Posted by roulhs View Post
any advice ?
thx

I agree that you should first take your time and learn the basic stuff.

You must know how to take good measurements. And more important and difficult is to understand what they show you. But you must learn this.

You are using a webside calculator for your speaker placement. This will not work. Never.

You say you know not how to take a proper measurement but you are expecting to be able to calculate the thickness of the perhaps required absorbers. This does not really fit well together.

I don´t want to demotivate you because it is really important and very good that you want to treat room and you should really do it.


But please take your time to first get the basic information you need to be prepared to really treat your room successful.

Speaker placement methods

This is a method that is used for speaker placement. And it works in your room.

Please stop guessing that you will need a certain amount of panels or you will fail. Rather buy some packages of glasswool or rockwool and put them at different spots in your room to see what they do. You need to get a feeling what treatment is doing in your room.

The only persons that can calculate what treatment is needed in your room are the professional acoustic room designers here in the forum. They do this for a living. Daily. They have all the tools. And even they have to take measurements in the building phase to see if their plans are working.

You find so much good information in this forum here.

Room EQ Wizard - Before & After - Need Help Interpreting Results!

Read this thread. It has good information.

And if you search for a post that shows you an easy way that you can copy then please stop searching for that post. Learn the basic things you need. The professionals here in the forum are and have always been very helpful. But you will need to be able to show useable measurements.
Most of the professionals here have multiple times written the important things. If I were one of them i would expect that the people first search. And i do not believe that any of them will give you not an answer to an specific question. But it will show the needed respect if you can show that you took your time to first search for the answer yourself and that you used all the info that they shared for free here to prepare yourself a bit.

Tom
Old 8th September 2018
  #15
Here for the gear
 

thanks for the reply and for advices,you ve right i should learn the basics first
so after search i managed to take measurements
these are my results
i took the measurement from both speakers at the same time
the mic i use is nti1a
Attached Thumbnails
Monitors placement/room acoustic-15-20000.jpg   Monitors placement/room acoustic-40-1000.jpg   Monitors placement/room acoustic-500-3k-hz.jpg   Monitors placement/room acoustic-3k-20k-hz.jpg   Monitors placement/room acoustic-filtered-ir.jpg  

Monitors placement/room acoustic-impulse.jpg   Monitors placement/room acoustic-impulse1.jpg   Monitors placement/room acoustic-rt60.jpg   Monitors placement/room acoustic-waterfall-20-20k-hz.jpg   Monitors placement/room acoustic-waterfall-20-500-hz.jpg  

Monitors placement/room acoustic-waterfall-500-3k.jpg   Monitors placement/room acoustic-waterfall-3k-20k.jpg   Monitors placement/room acoustic-spl-phase.jpg   Monitors placement/room acoustic-filtered-ir.jpg   Monitors placement/room acoustic-impulse.jpg  

Monitors placement/room acoustic-impulse1.jpg   Monitors placement/room acoustic-rt60.jpg   Monitors placement/room acoustic-spectogram.jpg  
Old 8th September 2018
  #16
Gear Head
 

Quote:
Originally Posted by roulhs View Post
thanks for the reply and for advices,you ve right i should learn the basics first
so after search i managed to take measurements
these are my results
i took the measurement from both speakers at the same time
the mic i use is nti1a

Sorry man,

read the stuff that i linked to exactly. You will not be able to tune your room.
I can promise you this.

You need a measurement microphone. There are cheap ones out there. 60 bucks or so. Do a google search and inform yourself which mic options you have.

I did not even look at your measurement as i read which mic you used.
Learn the basics. Learn them. And do not just assume that you learned them.

This will take time. Take this time. Rather spend now a week or two (most likely more) to get the stuff you need in your head and then come back here.

Most likely after learning what you really need you will not need to come back to any forums. It is your room.
And if you want to treat your room then learn how it is done.
All you can get here are overviews about things that perhaps work and things that perhaps not work and things that should be avoided. But this can be easily found via a search in the forum.
At the end of the day it will be you alone in your room till it is finished.

Tom
Old 8th September 2018
  #17
Here for the gear
 

Quote:
Originally Posted by tomthetom View Post
Sorry man,

read the stuff that i linked to exactly. You will not be able to tune your room.
I can promise you this.

You need a measurement microphone. There are cheap ones out there. 60 bucks or so. Do a google search and inform yourself which mic options you have.

I did not even look at your measurement as i read which mic you used.
Learn the basics. Learn them. And do not just assume that you learned them.

This will take time. Take this time. Rather spend now a week or two (most likely more) to get the stuff you need in your head and then come back here.

Most likely after learning what you really need you will not need to come back to any forums. It is your room.
And if you want to treat your room then learn how it is done.
All you can get here are overviews about things that perhaps work and things that perhaps not work and things that should be avoided. But this can be easily found via a search in the forum.
At the end of the day it will be you alone in your room till it is finished.

Tom
Before i take measurements i searched if i could use the rode nt1 for it cause i knew that i need another type of mic but on my first search i found that

Room Eq Wizard and Rode NT1
Old 8th September 2018
  #18
Gear Head
 

Quote:
Originally Posted by roulhs View Post
Before i take measurements i searched if i could use the road nt1 for it cause i knew that i need another type of mic but on my first search i found that

Room Eq Wizard and Rode NT1
This is what i meant.

It looks like you are trying to go the easy road.

Quick search after a post that shows what i want to read.


I mean the man with the mickey mouse recommends an measurement mic in this post…


And he also says that it is worth to learn how to use REW.


Stop playing and guessing and searching. Buy a mic. Take measurements. Try the stuff with RTA for speaker placement. Buy few packages of glasswool and throw them at different spots in you room and take measurements.

After a while you will see that the problems will just go if you have thrown a huge amount (much much more than you now expect) of packages with glasswool in your room.


There you have it. measuring. throwing glasswool packages in rooms. Room Acoustics are fun - aren´t they?


I am out here. Sorry. I have the impression that you want a quick solution. This will not happen. Just if you hire a professional. They will be quicker.

I am no professional. You can look at my thread to see what i have done in my room. Take also a look at the frequency response.


greetings and out


Tom
Old 8th September 2018
  #19
Here for the gear
 

okay okay guys.I am trying to find the best quick solution cause i am not an engineer .i am a musician and my projects are running.yes,acoustics are not funny to me.They are just a necessary step to improve the quality of my music.I am not playing here.i am not here to learn about acoustics.i dont even have time for that.i am here to take advices from you, cause you know and appreciate all for your answers.acoustics isnt my job..I gonna treat my room anyway,if you keep help me with these measurements or not.If someone want to see my measurements and have something to tell me ok.if not its ok again
Old 9th September 2018
  #20
Lives for gear
Quote:
Originally Posted by roulhs View Post
okay okay guys.I am trying to find the best quick solution cause i am not an engineer .i am a musician and my projects are running.yes,acoustics are not funny to me.They are just a necessary step to improve the quality of my music.I am not playing here.i am not here to learn about acoustics.i dont even have time for that.i am here to take advices from you, cause you know and appreciate all for your answers.acoustics isnt my job..I gonna treat my room anyway,if you keep help me with these measurements or not.If someone want to see my measurements and have something to tell me ok.if not its ok again
My help:

Learning is free.

If you don't want to learn, pay someone!
Old 9th September 2018
  #21
Here for the gear
 

Quote:
Originally Posted by JayPee View Post
My help:

Learning is free.

If you don't want to learn, pay someone!
first, i think forum is for helping each other
i dont say i dont want to learn, i want to learn i keep reading other threads,articles,watching videos etc but its not my job
so i cannot be expert at this because i dont have much time for this
i just want some advices to start a simple treatment at my room
thats all
acoustics is not my job,i am a musician

second
everybody here post their measurements and ask for advices
i did the same thing,what's the problem, i cant understand

lastly
i ask for some advices not for total analysis
if i had money i would hire a professional and not searching and asking in forums
also if i had money ,i would have plenty of time to full learn acoustics

ps: i never was ironic,i find ridiculous to be ironic in forums and playing with words (just to show yourself about your knowledge level )and at the end not to help
Old 9th September 2018
  #22
Here for the gear
 

so,
i tried to learn some things about measurements that rew gives
i am a little bit confused so lets take the things from beginning

i gonna start with low frequencies

so,we are talking about under 400hz.s i uploaded spl&phase and waterfall at 20-400hz below.so,just looking at my spl&phase i can see deeps and peaks at some frequencies.As i read the solution i am trying to find is how to balance these differences with adding bass traps and changing their place over and over to take the best results.also as i read waterfall is pretty helpful for low frequencies.i understood that waterfall shows you which frequencies take longer to decay(these frequencies are seem to be louder and hide the others?).so the solution here is the same.Balance between different frequencies.

consequently ,to go to next level what i have to do?i have to make some bass traps that can absorb frequencies that have big decay time?i mean to make bass traps and move arround to change their place or change their place over the corner i need to know what frequencies i have to absorb, right?if i know what i have to absorb i know the density of the material inside and the dimensions of my bass traps?

i took new measurements.uploaded images below
Attached Thumbnails
Monitors placement/room acoustic-20-400-hz.jpg   Monitors placement/room acoustic-spl-phase-20-400.jpg  
Old 9th September 2018
  #23
Here for the gear
 

maybe i should give to waterfall more ms to make things more obvious so i upload again waterfall
Attached Thumbnails
Monitors placement/room acoustic-20-400hz-waterfall.jpg  
Old 9th September 2018
  #24
Gear Head
 

Quote:
Originally Posted by roulhs View Post
maybe i should give to waterfall more ms to make things more obvious so i upload again waterfall

Hey roulhs,

you should really buy a measurement mic. You will need it.

I do not think that your cheap rode condenser is the right tool here.

Then do first the thing that Tomtom posted. The Speaker Placement Link.

Read the REW Manual how to use the RTA option. Then move one speaker and the mic in the room around like described in the link that was posted. Look only at the bass frequencies, below say 200-300 hz.

Your target while doing this is that the peaks and dips come together as close as possible in the bass frequencies.
In your last shown picture here the highest peak is at around 120 Hz, and the deepest dip is around 60 HZ. The peak is at 150 db and the dip at 110 db. This means a 40 db difference between the two. Your target after treatment is a max of 6 db difference. Move mic and speaker till you get the least amount of difference here. Maybe you can improve it to a difference of just 15 - 20 db just with better placement of listener and mic. After that you see which problems are still there and then you have to look how you can address those problems.


cheers
Old 9th September 2018
  #25
Lives for gear
Quote:
Originally Posted by Jens Eklund View Post
In a room that is too small for diffusers, this is what I normally do:




Not very different to what you describe. Deep porous absorption on early reflection areas and variable width/gap slotted panel on other areas.
Hej Jens,

Nice room.
I'm confused, that room doesn't seem bigger: YouTube but has your Optiffuser on the rear wall.
Can you comment on this? Is the room with diffuser bigger enough to have it?
Is there a minimum you wouldn't recommend not having any diffuser?

tack så mycket!

J.
Old 10th September 2018
  #26
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Jens Eklund's Avatar
Quote:
Originally Posted by JayPee View Post
Hej Jens,

Nice room.
I'm confused, that room doesn't seem bigger: YouTube but has your Optiffuser on the rear wall.
Can you comment on this? Is the room with diffuser bigger enough to have it?
Is there a minimum you wouldn't recommend not having any diffuser?

tack så mycket!

J.
Hej


The room in the video, this room:




is 0,5 m longer than the other room: 4,9 m. Just long enough to benefit from diffusers. The ISD-gap is about 14 ms.

The smaller room is 4,4 m long

I would not use diffusers if the IDS-gap becomes shorter than about 14 ms, possibly 12 ms if the client really wants to use diffusers.
Old 10th September 2018
  #27
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Jens Eklund's Avatar
Quote:
Originally Posted by Lebowski666 View Post
I hear it sounding great in that room by just looking at the pictures.

side walls do not look parallel too each other and are at a good distance. Open area seems to be way less than 15 - 20 % in this case. I would fear flutter in a parallel situation.

For a moment i have to agree with a part of what Tomtom posted above. You seem to like it to go the other way round. There is a lot of talk about vertical vs horizontal slatting in rooms to find here. most agree on vertical at side walls + horizontal at ceiling.

I guess you are not caring about additional stereo spread that vertical slats can / should / whatever provide. Not everybody likes the widening.

I guess your target with this kind of slatting is to address the low reverb time after needed rockwool treatment. And I am pretty sure that you are addressing a mode with the slots. gaining some helmholtz response. please correct me if i think wrong.

By just looking at the back wall i assume a 120 cm height of the absorbtive part of the back wall. 60 cm up and down from ear height i guess.


The side walls can add a lot to a better reverb time. Would the ceiling also work if not angled? flutter?
have you done this on a straight ceiling.


I would fear some reflections from the back wall at a first look by rolling back to get the home stereo response, but it can be that it is impossible because of the angled walls you did in the room. This is what i meant with my post. It is art to make it work. one can not copy this by just looking at those nice pics. a lot of calculation and experience is hidden behind what the first look shows.


cheers
I normally use horizontal slats on side walls in order to avoid partial scattering back to the sweet spot that would arrive too soon compared to direct. On the rear wall I use vertical orientation in order to scatter in the horizontal plane as normal, more here: 1D diffusor - vertical or horizontal?

Yes, I angle any surface relative to opposite (if reflective above the modal range) in order to avoid flutter. If normal HH array (low perforation percentage), I want at least 12 degrees difference between the surfaces but if variable slats with higher perforation percentage, a bit less is ok.

Reverberation time is not relevant (or even applicable) in small room acoustics such as control rooms or recording rooms. Decay time (in the modal range) and the shape of the ETC is what matters.
Old 10th September 2018
  #28
Gear Head
 

Quote:
Originally Posted by Jens Eklund View Post
In a room that is too small for diffusers, this is what I normally do:


Not very different to what you describe. Deep porous absorption on early reflection areas and variable width/gap slotted panel on other areas.
Jens,

damn

I can not get that room picture out of my head.

I love the look of it.

Right now as i said i have everywhere apart from the first reflection areas at sides, ceiling and back wall the MLS pattern.

44mm wide and 20 mm thick slats and gaps according to the sequence.

The slats are painted with clearcoat.

If i look at your pics and then around in my room i feel like i am sitting in a garden shed.

If i do not take the laminated floor into the equation the slats cover just around 50 % of the absorbtive area in the room. I guess even less since i put them afterwards away from the first reflection areas - i did not like the spread they provided - sounded odd to me.

I hope for some extra "ms" of decay time by taking your pic as an example.

Is there a certain ratio behind the gap / slat width arrangement in the pic you posted?

Thanks
Old 10th September 2018
  #29
Lives for gear
Quote:
Originally Posted by Jens Eklund View Post
Hej


The room in the video, this room:




is 0,5 m longer than the other room: 4,9 m. Just long enough to benefit from diffusers. The ISD-gap is about 14 ms.

The smaller room is 4,4 m long

I would not use diffusers if the IDS-gap becomes shorter than about 14 ms, possibly 12 ms if the client really wants to use diffusers.
Thank you Jens for this explanation!

Last question if it's ok, any reason you chose a different pattern/design in both rooms? If I understood correctly, any design can be applied, it's all about the % covered, right?
Old 10th September 2018
  #30
Lives for gear
 
evosilica's Avatar
 

Quote:
Originally Posted by Jens Eklund View Post
Hej


The room in the video is 0,5 m longer than the other room: 4,9 m. Just long enough to benefit from diffusers. The ISD-gap is about 14 ms.

The smaller room is 4,4 m long

I would not use diffusers if the IDS-gap becomes shorter than about 14 ms, possibly 12 ms if the client really wants to use diffusers.
Am I right that you are talking about room lengths after treatment? So the room was longer before treatment was installed...
Thanks!
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