NEW DESIGN-Control room ,REALY need some comments!!

[duki]

Greetings to all.
This is my new design of controle room,I would be grateful for your opinions.
The controle room is in the basement,the ceilng floor and walls are made of solid concrete
25 cm thick.The sound barrier is wall 12mm plasterboard then 100mm rockwool and 24 mm plasterboard.The floor is on the neoprene rubber total thicknes is 80mm.

[Soundman2020]

Hi Duki,

Several comments:

The sound barrier is wall...

What do you mean by "sound barrier wall"? You already have six very thick concrete surface around the room 25 cm is ten inches, which is pretty thick), so you should have pretty good "sound barrier" with what you have already.

Any additional wall you put inside of that should be designed as an MSM system, to work along with the existing wall. It seems that you are proposing a three-leaf wall! You said:

The sound barrier is wall 12mm plasterboard then 100mm rockwool and 24 mm plasterboard.

That suggests that you are going to build another two leaves inside of your existing 25cm concrete leaf. That would make three-leaves, which is usually a bad idea. You don't need it. At best, it won't do anything at all to help your isolation, at in the worst case it could even make your isolation WORSE in the low end, since it is three-leaf. But probably not, since the mass of the existing wall is very high already. However, you don't say how big the gap will be between your existing concrete wall and the new "sound barrier wall" ...

Also, using 12mm plasterboard is not a good idea: it is too thin, too flexible, and has a resonant frequency that is too high. Much better to use 16mm drywall (or 15mm if you can't get 16mm).

I'd suggest that you just put up a frame a few inches from the existing wall, and put one or two layers of 16mm drywall on only ONE side of that frame. And put rockwool in the air gap. That is plenty.

The floor is on the neoprene rubber total thicknes is 80mm.

Why do you need 3 inches of neoprene under your floor? Do you mean that the existing concrete floor is already on top of three inches of neoprene ? Or do you mean that you plan to lay 3 inches of neoprene on top of the concrete, then build the room on that? You most likely do not need that either. What is underneath the concrete? Is it directly on the ground, or is there another room below? Why do you think you need neoprene on the floor?

Some more comments:

1) The room is nearly square, and is not based on any known good ratio. I'd suggest that you adjust the dimensions to get closer to a good ratio.

2) The layout of the room is not good at all. Your mix position is much too close to the rear wall. Ideally, the mix position should be at roughly 38% of the distance from front to rear, but your looks to be more like 65 or 70%. (For the room dimensions you gave, your ears should be roughly 1.67 m from the front wall). I'd suggest that you move everything closer to the front of the room. It looks like the only way you can get good geometry in there is to soffit mount your speakers (which is always a good idea anyway!).

3) You seem to have a hard coupled link between your control room and your live room. You might want to fix that.

Please provide as much information as you can on your build.


- Stuart -

[duki]

Thans Stuart for your comments,they are very helpful.
-sound barrier wall-
If I understand well I should mount two layers of 15mm plaster boards on one side of the
drywall?The question is which side,near to the concret wall or inside the control room or not relevant? I prefer the plasterboard to be inside the control room.
I need sound barrier because of the ther is apartmant upstairs and because I have to separate live room from control room.
-FLOOR-
With floor I meant the neopran ruber 10mm thick and wooden beam 45mm x 50mm hight over the ruber then OSB panel 18mm thisck over the wooden beam and then laminate floor(estetic).
Between woden beam is rockwool 50kg/m3 50mm thick because of the hight of the room which is very small 260cm minus 10cm sound barrier and 30 cm of rock wool under barrier etc.

1) The room is nearly square, and is not based on any known good ratio. I'd suggest that you adjust the dimensions to get closer to a good ratio.
This is only predesign,I am aware of the room ratio but I prefer first to understand better the sound barier.
PS sorry about my english.

[Soundman2020]

If I understand well I should mount two layers of 15mm plaster boards on one side of the drywall?

On one side of the studs, yes. "Drywall" and "plasterboard" are two words for the same thing (also called "sheetrock" and "gypsum board"). The "studs" are what hold them up. So yes, you want two layers of 15mm drywall/plasterboard/sheetrock/gypsum board on only one side of the studs.

The question is which side,near to the concret wall or inside the control room or not relevant? I prefer the plasterboard to be inside the control room.

It doesn't really matter which side you put it on, as long as the gap between your concrete wall and the surface of the plasterboard is at least 4 inches (10cm). If you put the plasterboard on the other side of the studs (facing the concrete) then that is called "inside-out" wall construction. If you put it on the room side, then it is called "normal" wall construction. There are advantages and disadvantages both ways.

I need sound barrier because of the ther is apartmant upstairs and because I have to separate live room from control room.

OK, so that suggest that you have one large room that you are going to divide into two smaller rooms: the control room and the live room. Is that correct?

With floor I meant the neopran ruber 10mm thick and wooden beam 45mm x 50mm hight over the ruber then OSB panel 18mm thisck over the wooden beam and then laminate floor(estetic). Between woden beam is rockwool 50kg/m3 50mm thick

That is not a good idea. That is called "floating the floor", and the way you describe what you are planning is not going to work very well. You would be building a resonant box like that, and it would vibrate at certain frequencies. It would probably make your isolation worse! That would a thin, lightweight floor on top of a small air gap, so the resonant frequency would be fairly high.

But since you have a thick concrete floor, the best idea is probably just to put the laminate floor directly on top of that, for the control room at least. For the live room, you might want to build "risers", which are basically decoupled platforms that you put instruments on, such as your drum kit, or bass amp, or things like that. This is to prevent impact noise and direct vibration from getting into the floor.

What is under the floor? Another room, or just dirt?



- Stuart -

[duki]

Hi Stuart thanks again.

About the walls its clear for now.

About ceiling is the same like the walls(stud 100x40mm and over stud 2x gypsum board 15mm)?

OK, so that suggest that you have one that you are going to divide into two smaller rooms: the control room and the live room. Is that correct?
Yes one large room that I am goning to divide into two rooms,but first I need to work out the details about the construction(walls, ceiling,floor..) and then make a drawing of all.

What is under the floor? Another room, or just dirt?
Under the floor is just dirt.
About the floor I am thinking doing like on the pictures what do you think Stuart?
The thickness of the OSB board is now 40mm thick,but smaller air gap.
The other picture show the wall on the concret floor.

[Soundman2020]

About ceiling is the same like the walls(stud 100x40mm and over stud 2x gypsum board 15mm)?

Correct, but the dimensions of the joists (the "studs" for the ceiling are generally called "joists") will depend on the type of wood you use, the distance that they have to span, and the load that they have to support.

Also, the joists must be supported ONLY by the new stud wall: They cannot be supported by the outer wall, and they cannot even tough it: They must be "decoupled".

Yes one large room that I am goning to divide into two rooms,but first I need to work out the details about the construction(walls, ceiling,floor..) and then make a drawing of all.

I think you are doing it backwards: First you need to draw the rough layout, taking into account things like room rations, speaker position and mix position geometry, soffit mounting (if any), wall splaying (if any), reflection free zones, etc. And then, once you have all that in place, then you can start thinking about construction methods. You might well need to adapt your construction methods to the realities of your room layout.

Under the floor is just dirt.

Great! Then you already have very good damping for your floor, and impact noise is probably not going to be much of a problem.

Next question: How loud will you be? What is the estimated SPL level that you expect to be producing in: A) your control room, and B) your live room?

The thickness of the OSB board is now 40mm thick,but smaller air gap.

That still isn't very much mass, and the air gap under it is very thin. Plus, you don't need a floated floor at all. Here is a thread that you might find interesting:

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

The other picture show the wall on the concret floor.

That is the method that I would use. You should put some kind of underlay underneath the laminate.

Also, what is the purpose of the neoprene under the wall? If it is there to seal the gap, then great: that will work. But if it is there to try to "float" the wall, to decouple it form the floor, then that most likely wont work. Floating a wall is like floating a floor. You have to do it right if you want it to work. If not, then you waste a lot of time, money and effort, and you get no results.


- Stuart -

[duki]

Hi Stuart thanks alot.

For the ceiling its clear for now.The wall ,my thinkig was to float a wall and seal the air.

[b]I think you are doing it backwards.[/b]
This details that you are leading me through now are important for me to know before I start drawing.
No it will not be a soffit mounting and wall splaying .I am planing to make Helm Holtz resonators modular for lowend(in the corners),lowmid and mid frequences on the side walls and some gobos on the front and back wall,the ceiling is covered with the rockwool 30cm thick.

You should put some kind of underlay underneath the laminate.
Yes it will be underlay underneath the laminate.

You have to do it right if you want it to work.
What do you mean,something is wrong with floating the wall or I dont nead to do this?

In next few days I will make a drawing.

Regards

Duki

[Soundman2020]

No it will not be a soffit mounting

You might want to reconsider that. There are many benefits to soffit mounting your speakers, and in your case one of those benefits is that it gets your mix position as far forward as possible in the room, which is something that you really do need to do, as the space is so small.

I am planing to make Helm Holtz resonators modular for lowend(in the corners),

That might not be a good idea. Small rooms need a lot of broadband bass trapping, not necessarily trapping that is tuned to specific frequencies and with a very narrow Q. Something like "superchunk" bass traps in the corners, or hangers, or even just thick absorption across the corners, would probably be a much better idea.

and some gobos on the front and back wall,

I'm not quite sure what you mean by "gobo" in that context, since gobos are usually movable panels, absorbent on once side and reflective on the other, used to help isolate instruments, amps, etc. I can't see how putting those on your front and rear walls would help very much.

Your front and rear walls will most likely need some fairly thick absorption (10cm to 15cm, probably), at least in some parts. The front wall needs it because it is a first reflection point, especially if the speakers are not soffit mounted. The rear wall needs it to help deal with reflections coming back at our head from behind.

What do you mean,something is wrong with floating the wall or I dont nead to do this?

Both! If you are going to float a wall, you need to do the calculations to ensure that you are loading the neoprene correctly, with just the right amount of weight. If you put too much weight on it, then it will over-compress and will not isolate the wall from the floor, so it wont float. And if you don't put enough weight on it, then it won't be compressed at all, so it won't isolate. You have to use just the right amount of neoprene (correct dimensions, correct type, correct thickness, correct location) for the wall that you are going to put on top of it. To do it right, you have to know the technical characteristics of the neoprene that you have to use, such as exactly how much compression you need to put on it in order to load it correctly (how many kilograms per square centimeter), then you need to know exactly how heavy your wall will be, and how that weight will be distributed, then you need to calculate the surface area of neoprene that you need at each point under the wall, etc. It can be done, but it isn't easy. If you don't get it right, the wall won't float and you wasted your time. But if you aren't worried about floating it, and just want to use the neoprene to get a better seal, then that's fine: just be aware that it will not be giving you any acoustic benefit, and ordinary caulk would be much cheaper and just as good at sealing. In any event, the building code in your area might not even allow you to build a wall that is not attached to the floor: Where I live, you cannot do that, due to frequent earthquakes that we have here. Here, the wall MUST be bolted to the floor, and as soon as you put a bolt through the neoprene, then obviously you have created a flanking path, and the wall is not floating any more.

And in any event, you probably don't need to float your walls, for the same reasons that you don't need to float your floor.

- Stuart -

[duki]

Hi Stuart

The wall,I understand what you mean.

The soffit mounting I dont want to do that because in time I want to change my speakers.

About the GOBO I mean like on the picture.

There are also broadband HelmHoltz absorbers I produce them my self,check the picture and link,I nead your apinion about that.
http://www.trikustik.at/fileadmin/media ... _R16D8.pdf
I have already done my room(home theater for my family) with perforated HelmHoltz resonators.Now I am doing my basement which is the curent design.
Here is the link.Also what is your opinion?
http://www.johnlsayers.com/phpBB2/viewt ... =1&t=14203

[duki]

Where are you Stuart ??

[Soundman2020]

Where are you Stuart ??

Busy!

Try to get back to you later. Running around all over last few days...


- Stuart -