Studio/listening room design in Belguim

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Dirk
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Studio/listening room design in Belguim

Post by Dirk »

Hello, I'm from Belgium, and new to this forum, but have already read a lot of topics here and learned alot ! I’m a real fan of this site. Other stuff I’ve read : Handbook of acoustics, Rod’s book, etc. The main principles are clear, but I have a few question that need clarification before I even start the build of my little home studio/ listening room in our new house, to be sure that I don’t mess things up :o)!

It will be located on the third floor under the roof. Not the best place, I know, but I’m already happy that I have that space. I will build according to all the info I’ve read in the books above and this forum. Room in room, according the little studio design from John.

Purpose of the room is to listen to music in excellent sound-conditions plus record some guitar and vocal stuff for my rock – metal band (electronic drums), and then mix it all down. The type of music I listen to is mostly hardrock - metal and beyond, but also pop music. So a wide variety. My speakers are a Tannoy 800 System, for the moment no subwoofer, but I'm thinking about it. I've learned to not play to loud anymore (ears !!), so most of the time it will not be louder than 80db, sometimes a bit more when it has to :o).

The space I have, to build the room in, is 6,5m length * 3,5m width * 2,5m height. It’s located on the third floor, under the roof, so the front and rear are angled. See the sketchup picture, it's where the beams are drawn : "zolder1.jpg"

In the rear roof part there’s a window (double glass).

The floor is concrete (16cm) with another layer of 10 cm of what we call ‘chape’. That’s a mixture of sand (like the one you find on beaches), cement and water. It’s used to level all the electrical and water leads. On top of that there comes a finish of 1cm vynil (after the construction has ended).
The walls of our house are from inside to outside :
- brick wall (14cm)
- 12cm of recticel PUR isolation attached to the 14cm brick wall (excellent for thermal isolation, but acoustical close to nothing, because closed cells. Weight also close to nothing)
- 3cm air space
- 9 cm brick wall
- the outer leaf is anchored to the inside with metal hooks of about 0,5 cm diameter in the mortar.
See attachement "wall construction.jpg".

The right wall (see sketchup) of my space is also a double wall but from inside out :
- a brick wall of 9cm
- 12cm Pur isolation attached to the 9cm brick wall
- 3cm air space
- 14cm brick, not anchored to the inside wall. The 2 leafs are build on the concrete floor.

Since it’s a house in the row, next to this wall,there will be neighbours (house still to be build) in the future. Regulations are that there has to be a fibreglass or rockwool layer of 4cm in between 2 buildings. So the neighbours house will be freestanding.

The left wall = 9cm brick wall with a door (see sketchup picture). On the other side of that wall, the kids have their space for video gaming, playing etc. So there can be sometimes a lot of noise… I will not be recording then, but maybe listening to music or jamming...

The roof :
- beams of 18cm with fibreglass isolation in between of 18cm.
- A wind and rain shield something(polyester stuff)
- Roof-tiles (see picture in attachment "roof with window.jpg")
The inside of the roof looks like picture "Isolatie Dak.jpg"

With all this info I hope you experts can give some answers to my questions :
1) Is the right wall already a double leaf (this was done for thermal insulation, I was already aware that this was going to be a problem :( )? Or will it act as one leaf? Because when I build my room next to it, that will be then a 3-leaf system. And that is to be avoided most of the time. Also the middle leaf would be 9cm, and that too is not good, because the middle leaf should be the heaviest in mass. Or can I use this 9cm wall as my left wall of the studio ? But then the right and left wall of the room will not be the same (inner room will be metal studs and gyproc (2 layers).

2) A bit the same question about the rear and front wall of my studio. Is the roof with the beams + roof-tiles (50kg/m²) the first leaf ? So when I add say 2 layers of gypsum to the beams, this would be the second leaf of the MSM system. When I then build my room decoupled from this, I end up again with a triple leaf system? So is it best not to put gypsum on the beams, and just build my room’s wall’s say 10cm apart from it ?

Thanks in advance for the help !!
Dirk.
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Re: Studio/listening room design in Belguim

Post by Dirk »

I think I already found the answer to my second question. It will be a triple leaf if I put drywall directly on the beams of the roof and put my wall in front of it. So I will just put the wall seperate from the roof.

My first question although still stands... anyone ?? If more info is needed or my post is not correct, please let me know...
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Re: Studio/listening room design in Belguim

Post by Soundman2020 »

Hi Dirk, and welcome! :)
It will be located on the third floor under the roof. Not the best place, I know, but I’m already happy that I have that space.
As people often say here: If that's what you have, then that's what you have, and it sure is better than not having any place at all!
Purpose of the room is to listen to music in excellent sound-conditions plus record some guitar and vocal stuff for my rock – metal band (electronic drums), and then mix it all down.
Is that the order of priorities? First and most important, it is a critical listening room, then second a tracking room, and least important a control room?
The space I have, to build the room in, is 6,5m length * 3,5m width * 2,5m height. ... The floor is concrete (16cm) with another layer of 10 cm of what we call ‘chape’. That’s a mixture of sand (like the one you find on beaches), cement and water.
That sounds like quite a reasonable place, actually. The angled parts might be a bit of an issue, but over all it sounds good.
1) Is the right wall already a double leaf
Yes, but with the mass of the bricks on both leaves, and the 15cm air gap, I doubt it will be problem for you, if you build a third leaf next to it. You are not planning to track very loud or low frequency instruments, and your listening volume is very reasonable, so I don't think this will be a problem.
2) A bit the same question about the rear and front wall of my studio. Is the roof with the beams + roof-tiles (50kg/m²) the first leaf ?
Yes.
So when I add say 2 layers of gypsum to the beams, this would be the second leaf of the MSM system. When I then build my room decoupled from this, I end up again with a triple leaf system? So is it best not to put gypsum on the beams, and just build my room’s wall’s say 10cm apart from it ?
Here too I don't think it will be a problem, for the same reason as above: no loud, low-frequency instruments, low listening levels, etc. You could probably go either way here: leave the roof alone and just build a second leaf for your room, or put a ceiling in on those rafters and build your room as a third leaf. Either way will work. My concern would be how well the roof tiles are sealed: You mention a figure of 50kg/m² for the mass, but are there open gaps between the tiles? If so, then I would go with the 3-leaf system. In that case, even though the tiles are plenty massive enough to be a 3rd leaf, the sound would still get out easily through the gaps. So the decision on "2-leaf or 3-leaf) for the ceiling depends mostly on exactly how the tiles are done. Can you get more info on that? A photo or diagram would be good.


- Stuart -
Dirk
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Re: Studio/listening room design in Belguim

Post by Dirk »

Hey Stuart,

First of all, thanks a lot for the answers. They give me already more peace of mind :D .

To answer your questions :
Is that the order of priorities? First and most important, it is a critical listening room, then second a tracking room, and least important a control room?
It's indeed first a listening room. Second priority wil be playing the guitar in it. Last it's a tracking room and control room. These last 2 go together when we record songs.
Yes, but with the mass of the bricks on both leaves, and the 15cm air gap, I doubt it will be problem for you, if you build a third leaf next to it. You are not planning to track very loud or low frequency instruments, and your listening volume is very reasonable, so I don't think this will be a problem.
Definitely no drums, from time to time guitars (direct or via amplifier), and bass guitar (via peavy 150W amp). But that will always be during daytime and I can check with my future neighbours if that would be any problem.
... but are there open gaps between the tiles? If so, then I would go with the 3-leaf system. In that case, even though the tiles are plenty massive enough to be a 3rd leaf, the sound would still get out easily through the gaps. So the decision on "2-leaf or 3-leaf) for the ceiling depends mostly on exactly how the tiles are done. Can you get more info on that? A photo or diagram would be good.
In attachment there is a picture of the way the construction is done (fot dakconstructie.jpg ) + 2 pictures of the finished roof (foto dak1.jpg and foto dak 2.jpg) of how the finisched roof looks like. Seems like there are airgaps enough ??

I have also purchased a decibel meter (Voltcraft SL-100) and did some measuring today. In the room I had some metal record (Caliban, The awakening) playing, which is rather heavy stuff :evil: . Here are the figures :

Inside the room : 90dbA
In the kids playing room (next to mine) : 65 dbA
On the second floor in all the rooms : between 40 and 45 dbA
Outside next to the double leaf brick wall (I went 6m up a ladder to measure :D) : 50dbA, and low frequencies where rather good to hear.
In the backyard (40m from our house) : 40 dbA
In front of the roof, where the double glass window is (yep, the same ladder up again) : 55 dbA
In front of the house accros the street (10m distance) : nothing to hear (speakers fire the other way (see picture "foto ruimte 1.jpg"))

So, apart from the kids playing room, there is a loss of about 40db around the building. I think that's already quite good ? So for the roof part, should I go for triple leaf or double leaf ?

In the pictures "foto ruimte 1.jpg" and "foto ruimte 2.jpg" you can see the build on the inside of the room. The brick walls are not plastered and only on the horizontal line there's mortar (for thermal insulation reasons). I think it's best that before I start the inner construction, that I plaster both walls. This will gain me some decibels to start with.
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Re: Studio/listening room design in Belguim

Post by Dirk »

Hello, it’s been a long time since I posted something, but have been reading and studying further on building my music room. And after several months of work, the walls are finished! They are : side walls : double layer of drywall (12,5cm each), green glue between them, metal studs, and an air gap of 10cm, filled with glass-fiber. front, back and ceiling : the same, except for the metal studs, that's this thing :
Akoelat 60.jpg.zip_20111107114456_0.5546.jpg
It's 2 pieces of MDF with a decoupler between, called vibrablock. It's the same as accorub, sylomer, etc.
The first piece of MDF is screwed onto the roof beems (see pictures in first post). The drywall is then screwed onto the inner MDF piece.

Some pictures :
Front wall.jpg
back wall.jpg

I’m now at the point where I can start with the speaker placement and treatment of the room. I’m thinking as mentioned in my previous posts above, to make the room like a RFZ design.

Final room dimensions: 6,36m * 3,24m * 2,42m (Length * width * height).

I’ve moved around with my speakers (Tannoy System 800) playing some of my favourite music (metal) and taking measurements with REW. I placed them along the short wall, and the long wall. Here-under is what I find to be the best sounding place so far (also see pics).

At the moment, my speakers woofers are at 90cm from the side-walls, height is 120cm and they are angled so that they fire at a point 30cm behind the listener’s position (38% from the front wall). So I don’t have a perfect triangle, because the distance between the speakers is 144cm, and about 200cm to the listener’s position. I tried moving forward to sit in the perfect triangle, but it doesn’t sound as good (sound stage, stereo-image) as at the 38% position. So I think that’s where they will stay and that I’ll work from there.

Here are the measurements in REW, right, left and both speakers, microphone is the Behringer ECM800 (files on google drive, but shared from this link) :
Right : https://drive.google.com/file/d/0B-GyUY ... sp=sharing
Left: https://drive.google.com/file/d/0B-GyUY ... sp=sharing
Both : https://drive.google.com/file/d/0B-GyUY ... sp=sharing

As you can see in the pictures, the speakers are under a sloped wall, what is a problem. I’ know.
I think about soffit mounting my tannoy’s. They are passive, and the bass-port’s are front-firing, so that should not be a problem.

So now it’s question time :
1) Is the sloped wall a problem for the soffit mounting ? Where the speakers are now, I have only 10cm to the back-wall (shortest distance) and 30cm from the lowest part of the speaker to the sloped wall. Is this still enough to have the “infinite baffle” effect ?
2) If soffit mounting is ok, what effect will the sloped wall do ? Still extend the infinite baffle effect ? Or do I already have to treat it (first reflections) ?
3) About the measurements :When I look at the left and right data, I think that it’s not really bad ? But looking at the data of both the speakers, the low end is completely gone. But playing a cd, I do hear a good bass… What happens here ?
4) Do I even have to care about my current measures when soffit mounting, or is this the ideal starting point ?
5) About the rear wall. Those closets need to be their (my own design :), I have to put my books and other stuff in there). For the closet doors, I'm working on a door frame that can hold rockwool of 5cm that will just be covered with cloth. The frames of the doors is about 5cm width. The closets themself are 50cm deep. So that can give me some absorption, and eliminate most of the reflections. Next to the closets, I have a gap of 20cm (also 50cm deep) that I will completely fill with rockwool or glass-fiber, sort of mini-superchunk... The sloped wall, will also have to be treated, but I don't know yet how I will do that. I hope this will be enough for that back-wall ?

That’s it for now, Already a big thanks for the answers !!
Dirk.
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Re: Studio/listening room design in Belguim

Post by Dirk »

Anyone please ??
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Re: Studio/listening room design in Belguim

Post by Dirk »

I have been doing some more measurements :

https://drive.google.com/file/d/0B-GyUY ... sp=sharing

It's now a test on the short wall and one from the long wall. Since everyone says (and I understand the reasons why), that the speakers should be on the sort wall, I was doing test there, but was not able to get decent bass response according to the rest of the freq. rang. So I tried again a test on the long wall, and tedaa, more bass. But a big spike on 180 Hz.

So the confusion only gets bigger.
And soffit mounting on that long wall is no option I think ? My speakers are approx. 2 meters from the side wall...

Thanks for helping me out :(
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Re: Studio/listening room design in Belguim

Post by Dirk »

Here are some sketchup files of my room. first a 2 views on the setup on the short wall. There is also a first attempt to put some ray tracing in it to detect first reflection points :
RFZ short wall.jpg
RFZ short wall 3D.jpg
Views on the setup on the long wall :
RFZ long wall.jpg
RFZ long wall 3D.jpg
Some graphs from the measurements above :
short + long wall spl 45 - 300 hz.jpg
short + long wall spl 45 - 20000 hz.jpg
short + long wall spl 45 - 300 hz watherfall.jpg
Hopes these pics and graphs will help to get some answers :( .

Additional questions (see also my previous questions (1 to 5) :
6) I think a subwoofer will help for those low frequencies ?
7) For the long wall setup, I think that soffit mounting is still in the picture ?
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Re: Studio/listening room design in Belguim

Post by Soundman2020 »

So I tried again a test on the long wall, and tedaa, more bass. But a big spike on 180 Hz.
Right! Because your listening position is now in the modal null or SBIR null for that frequency. That's why the general recommendation is to have the speakers on the short wall, firing down the long axis.
There is also a first attempt to put some ray tracing in it to detect first reflection points
You don't need to trace so far off-axis: there are mostly only low frequencies that far off-axis, which don't act like rays. Tracing out to about 50 or 60 degrees off axis is usually fine.
So the confusion only gets bigger.
You did those tests with no treatment in the room, so you can't judge how the room will sound once you start treating it.

- Stuart -
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Re: Studio/listening room design in Belguim

Post by Dirk »

Stuart,

Thanks for the reply :D !! I have returned to the short wall speaker placement. As in the drawings with RFZ short wall.

I still want to do soffit mounting of my speakers, but the sloped wall is can certainly be problem for that... A first attempt in sketchup (the light grey above the speakers is the sloped wall :) ) :
RFZ-design short wall test flush mount walls.jpg
I found an earlier post of you stuart, where you say that the "infinite baffle" for the soffit wall should be a quarter-wavelength of the cutt-off frequency of the speaker. For the tannoy system 800's, that is 47Hz, so the infinite baffle should be at least 1,8m. The lowest point of the baffle is 1,4m approx. the highest almost 2m...

So can I ask again following questions, because I don't really have an answer to them yet :
1) Is the sloped wall a problem for the soffit mounting ? Where the speakers are now, I have only 10cm to the back-wall (shortest distance) and 30cm from the lowest part of the speaker to the sloped wall. Is this still enough to create the “infinite baffle” effect ?
2) If soffit mounting is ok, what effect will the sloped wall do ? Still extend the infinite baffle effect ?
You did those tests with no treatment in the room, so you can't judge how the room will sound once you start treating it.
That's true, but you do have to do those measurements to know what the problem area's are in the frequency responses, otherwise you're just treating the room without a starting point. I think that's correct ?

Thanks again for the replies.

Edit on 11 september, added a sketchup view + added the math for the quarter-wavelength thing to calculate the measures of the soffit wall...
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Re: Studio/listening room design in Belguim

Post by Dirk »

Anyone please ?? :(
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Re: Studio/listening room design in Belguim

Post by Dirk »

Anyone, Anyone Please ???
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Re: Studio/listening room design in Belguim

Post by Soundman2020 »

I have returned to the short wall speaker placement. As in the drawings with RFZ short wall.
Smart move! :thu:
I still want to do soffit mounting of my speakers, but the sloped wall is can certainly be problem for that... A first attempt in sketchup (the light grey above the speakers is the sloped wall :) ) :
It looks like it should be OK the way you are showing it there. I don't see too much of a problem.

However, you show the speakers laying down on there sides: it would be much better to have them standing upright.
1) Is the sloped wall a problem for the soffit mounting ? Where the speakers are now, I have only 10cm to the back-wall (shortest distance) and 30cm from the lowest part of the speaker to the sloped wall. Is this still enough to create the “infinite baffle” effect ?
It seems to be fine, from what I can see. It's the best option for you anyway, so I would go with that.
2) If soffit mounting is ok, what effect will the sloped wall do ? Still extend the infinite baffle effect ?
Yes. In fact, the side walls, floor and sloped wall/ceiling all act a bit like a horn, to a certain extent.
do have to do those measurements to know what the problem area's are in the frequency responses, otherwise you're just treating the room without a starting point. I think that's correct ?
Right! That's your "baseline" test, so you can see where your modal problems are, and also where you are getting SBIR and other phase cancellation issues. You can compare all your future tests against this to see what each piece of treatment accomplishes, what works, what doesn't work, and what you still need to be doing to get the room as good as it can be.
I found an earlier post of you stuart, where you say that the "infinite baffle" for the soffit wall should be a quarter-wavelength of the cutt-off frequency of the speaker.
That's ideal, yes, but if you can't make it that big, then any extension of the baffle is useful. It's good to make the baffle at least twice as wide as the speaker itself. Yours seem to be a very decent size.

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Re: Studio/listening room design in Belguim

Post by Dirk »

Hey Stuart,

Thank you very much for the reply. And you confirm every idea I had about my room and how to move on from here :D :D . I wil post further on my progress and come back when I have more questions.

About this :
However, you show the speakers laying down on there sides: it would be much better to have them standing upright.
These speakers are ment to be placed that way. It's a dual concentric speaker from tannoy,the system 800 passive. See for a picture my post on Sat Aug 23, 2014 10:21 pm. Those 2 wholes next to the woofer are basspipes. I did test the speakerposition in all directions (like shown in the drawing, standing up, with the bass pipes to the other side and upside down). It showed very little differences in the measurements. So I should be fine like this ?

Have a nice weekend everyone.
Dirk.
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Re: Studio/listening room design in Belguim

Post by Soundman2020 »

It's a dual concentric speaker from tannoy,the system 800 passive.
Ahhhh! OK, then you are fine. No problems there! :thu:

- Stuart -
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