Live Room Construction

Hi everybody, First of all I want to say thank you for this great forum. I have learned a great deal regarding acoustics and construction. You may have noticed that I am from Germany thus english isn't my mother tongue. I apologize for any shortfalls regarding my english and hope you don't mind me asking again if anything remains unclear to me. Is there a problem using the metric system for dimensions? It would be easier for me since its done that way in Germany. Overview Right now I am in a small rehearsal space with a very low ceiling, no heating installation nor sanitary facilities. Ever since I play in a band I do recording of some kind. Over the last years it became more and more recording other bands buying equipment. But the rooms are not up to the task. I found 2 rooms in an older building which seems suitable for a new rehearsal space/studio. The building is almost empty which means I can add rooms to my space any time. Right now some rooms are used for storage. The Landlord got his bureaus there too. He knows about my plans. Only downside its on the first floor. You enter from the corridor into the smaller room (22,2 m²) which will be my control. From there you enter the second room (84m²) which will be the live room. All walls are brick walls except for the wall between the rooms. This is made of ytong. Ceiling in both is about 3,70 m. In the smaller room it is already suspended with acoustic ceiling tiles for bureaus. The original ceiling is prestressed concrete (I hope thats the right translation). There are 5 double T beams in the live room. 1 on the ytong wall one on the brick wall and 3 inbetween. The ground floor is wood reinforced from underneath with double-t-beams. Probably done the same way my ceiling is done. The windows are double glazed windows. Doors will be replaced. Heating elements will be under the windows The drawing I attached is kinda rough...first try with sketchup..;)... Exact measurments will be made next weekend. Afterwards I will try and draw a 3D model. Together with the attached images you should be able to get a picture of the rooms. Goals: On top of the list is sound proofing the live room. I have no concrete idea on how much soundproofing is needed there. At the moment probably non because there is noone else there. What I don't want is to do everything all over again because I saved 200 € on materials this time. If there are things I can do to optimize this room acoustically along the way I will do so but treatment itself comes later and isn't what this thread is about. Î'd like to go for a room in room concept. Almost. The outer wall I would love to leave as is soundproofing wise. I plan on using non-bearing steel studs for the inner walls with 2 layers of 12,5mm gypsum and insulation. The steel studs are special designed acoustic studs as is the gypsum. I know the studs shouldn't touch any outside walls nor the ceiling. Regarding the ceiling I think spring hangers would be the easiest way The doors will be massive wood doors. I won't install a window from the live room to the control room. I will go for a CCTV system. 1. Does it make sense to leave the outer wall as is? 2. Wall construction: What should the construction of the walls look like? A gypsum drywall with steel studs can't be built free standing, can it? And probably not when its measuring almost 14 meters. 3. Stud size Which stud size to choose? 50 mm steel studs should be enough to carry a 2-layer gypsum wall. Or is it necessary to use 75 mm or even 100 mm studs? 4. Air gap: I don't mind losing 300 mm or more on each side if it is worth it. How much is too much (if there is)? 5. Insulation: This kinda depends on the studs I choose. As far as I read any rockwool (50kg/m³) or fiberglas wool (30kg/m³) will do. I have seen insulation filling measured in percent of the air gap? What about an 300 mm air gap with only 50 mm insulation? If I leave an air gap of 300 mm and need to fill all of it with rockwool it is gonna be expensive. So how much fill makes sense in absolute terms? Thats it for so far. Along the way there will be hundred more questions but these are the basic ones for now. I thank you in advance for helping. I will update this thread regularly. Best regards Daniel

Anybody willing to help me with this? Or did I leave out any information that makes helping impossible? Daniel

Hi, That looks like a great space to do a build in. Is there any chance you could cut another doorway between the two rooms closer to the entrance? That way you wouldn't have to go through the control room to reach the live room? It would make the access better. Steve

Hi, I thought about that too. if the monitoring position was facing the wall to the live room everybody would have to be walking around the mixer. Another option I considered is to have the mixing/monitoring position facing the opposite wall. Since I don't plan on having a window between both rooms I am independent in choosing my mix position. Thus I would also have more than enough space to the left and the right for outboard. It might feel a tad strange in the beginning to have the live room in the back but seeing it in front of me via cctv. Only real disadvantage regarding this solution I can think of now is I will have to get the all audio lines across the room. but this isn't that much of a problem I think. Anything else you might want to contribute. I am all ears. I want this to work out well. Thanks for the comment on my space. I think so too.. Best regards Daniel

Hi Daniel, I guess the first question I should have asked is how much isolation do you need? Have you taken any readings with an spl meter? How much traffic noise is there? Can You access one of the rooms below, get a friend to stomp around upstairs, or put on some loud full range music in your room.... I think you need a baseline to shoot for before starting your plans. Oh and how loud are you going to be in your live room? Steve

Hi... I am not able to awnser the question about how much isolation I need. Right now....next to none....there is nobody else there...almost. Adjacent buildings are about a hundred meters away...but only to the front....my place only got windows to backyard. There are rooms to the front which a separated by a floor from me. The place I am in is an old factory building. I don't think there will be anybody moving in here soon...but just in case there will I want be on safe side.... I have not taken any spl measurements yet....but will be as soon as possible and post results. The ”only” traffic noise I have is a railway but the installed windows isolate well. Sooner or later I will double them (window-gap-window). This can be done using the existing wall (outer wall) since space permits it. The airgap between the windows wwill then be about 25 cm. But this will come later. I will build plugs for them until the new windows will be installed. I have access to the rooms below and will do test using a my rhythem section without any isolation to the floor. Again, I will post results. I have been pretty busy the last weeks. Not only my studio will be moving.. I did too..;)... We play rock'n'roll...so its probably going to be a tad louder... Though I tend to turn down a bit as I get older. My main concern is isolation to my floor and the floor above me. But wood floor is kinda tough. And I don't want to even think about floating it...:-S... That's why my thoughts were dry walls and new ceiling. Oh by the way budget is about 6000€ for walls ceiling and. Electricity.... Thanks for helping so far...I really appreciate that.. Best regards Daniel

Hi... I am not able to awnser the question about how much isolation I need. Right now....next to none....there is nobody else there...almost. Adjacent buildings are about a hundred meters away...but only to the front....my place only got windows to backyard. There are rooms to the front which a separated by a floor from me. The place I am in is an old factory building. I don't think there will be anybody moving in here soon...but just in case there will I want be on safe side.... I have not taken any spl measurements yet....but will be as soon as possible and post results. The ”only” traffic noise I have is a railway but the installed windows isolate well. Sooner or later I will double them (window-gap-window). This can be done using the existing wall (outer wall) since space permits it. The airgap between the windows wwill then be about 25 cm. But this will come later. I will build plugs for them until the new windows will be installed. I have access to the rooms below and will do test using a my rhythem section without any isolation to the floor. Again, I will post results. I have been pretty busy the last weeks. Not only my studio will be moving.. I did too..;)... We play rock'n'roll...so its probably going to be a tad louder... Though I tend to turn down a bit as I get older. My main concern is isolation to my floor and the floor above me. But wood floor is kinda tough. And I don't want to even think about floating it...:-S... That's why my thoughts were dry walls and new ceiling. Oh by the way budget is about 6000€ for walls ceiling and. Electricity.... Thanks for helping so far...I really appreciate that.. Best regards Daniel

Yes, please take some measurements before really starting to design, as otherwise you may not get the results you need. If you are doing a ceiling, you probably need to do walls as well and make it a complete room in room. That includes the window wall. But if the isolation is almost enough without any treatment.... You may be able to fudge it a little bit. The brick wall.... The easiest solution is to use this as a wall for your controll room or live room. The other solutions are: 1) take it down ( as long as it is not a support wall) 2) build a 3 leaf wall and leave it in. But untill you know what you need....... Steve

I will take measurements for sure...as soon as possible.... What I want is isolation to the control room and maximum isolation to the rest of the building keeping in mind the budget. I attached a simple drawing of the rough idea. I will use steel studs. They will be free standing and for reasons of stabilty they will be attached but decoupled to the outer walls. The windows I meant are the outside windows. There will be no windows window between control room and live room. Best regards Daniel

If the red line is showing the location of the inner-leaf, then there's one side missing: it only shows three sides of the room, but you need to do all four. With only three sides done like that, there is no isolation. Nothing. Also, for the "kink" in the bottom left corner, it might be easier to just splay the wall there, especially if that is going to be the front end of your control room. Of course, you'd have to splay the "missing other side" in the same way, to keep symmetry.

What I want is isolation to the control room and maximum isolation to the rest of the building keeping in mind the budget.

Until you add the fourth wall, there's no isolation at all! - Stuart -

Hi... I understand that this not a true room in room concept since the new room is not totally decoupled from the rest of the building. Even if i did the 4th wall this would still leave the floor coupled. I thought that the outer brickwall being almost half a meter thick wouldn't transmit sound very well even low frequencies. I don't have any data at hand to prove that though. Am I wrong in my assumption? The drawn in walls, new ceiling and the resulting damped air gap (sealed of course) should provide good isolation as long as its built well with the right materials. The reason to not do the heavy outer wall is based on this belief ....and the fact that windows of this size are expensive...;)... Daniel

An interesting question. These concepts are emphasized again and again, but what if 1 of the four walls is already a 2-leaf structure, and/or perfectly isolating? Also. it seems to me, if the density of the wall in question is great enough, it's resonant frequency is low enough that airborn sound (ignoring direct mechanical vibrations) will not seriously conduct (flank) over to connected walls - at least this seems to be so from my own experience.

Hi... Can anybody else comment on the above scenario? what am I missing here? Is it so wrong to asume a wall of this size and weight will not transmit sound very well? best regards Daniel

Is it so wrong to asume a wall of this size and weight will not transmit sound very well?

What is the weight? If you can tell us that, then we can tell you what the theoretical isolation is, based on mass law. But mass law is not your friend.... - Stuart -

Hi... The outer wall is massive brickwork. Density of brick seems to be <2000 kg/m3, >1300 kg/m3 Based on that I suggest a medium density of 1600 kg/m3. With the wall being 0.5 m thick it has a weight of 800 kg/m2. The overall dimensions of the wall are 100 meter in lenght and 15 meter in height. Is that about what you asked for? Best regards Daniel

With the wall being 0.5 m thick it has a weight of 800 kg/m2.

More correctly, that is surface density, not weight. With a surface density of 800 kg/m2, transmission loss will be around 45 dB at 60 Hz, rising to about 65 dB at 4 kHz, theoretically. STC for that would be somewhere around 70-something, I guess. But that's just the wall itself. Those windows don't look to be very substantial (even though you say they are double-glazed), and I doubt that their TL is more than about 30-something, so the total TL for that wall is about 30-something. The isolation of the brick is irrelevant. All that counts in that wall is the isolation of the windows. Without properly sealing those, adding mass to them, and then adding an inner leaf, your total isolation of the room is limited to whatever those windows are capable of producing. That's the point I was making originally: if you only do three sides of that room as two-leaf decoupled MSM, then you have no isolation. Without the forth side being done correctly, your total isolation is the same as that of the weakest wall, which in your case is the monstrously massive but irrelevant brick, and the far less impressive windows. One possible solution: take out the windows and brick up the gaps to the same level as the rest of the wall. - Stuart -

Hi... I didn't know that word in english sorry...its a little bit different in german... I understood the point you were making in your first post. But, I don't need any isolation at that wall at all. At least not to the outside. My only concern is how much sound will be transmitted along that wall to rest of the house. Is that called flanking transmission..? Best regards Daniel

My only concern is how much sound will be transmitted along that wall to rest of the house. Is that called flanking transmission..?

So no other rooms in the building have windows in them? There are no doors to the outside? Yes, sound moving through the structure itself, and bypassing your isolation, is called "flanking" sound. But so is sound that goes out through those windows, then comes back in through the windows in the room next door... Or that gets into the windows or doors of other rooms in other parts of the building, or to buildings close by. That's why the room must be isolated to the same level on ALL sides. Isolating only 3, 4 or 5 sides is not enough: Once sound gets out of the room, by ANY path (maybe even through your electrical system, or ventilation system), then it is out, and there is nothing you can do to stop it. If it is out, then it will be heard in all other locations that are not isolated. This is especially important for low frequency sound, where the wavelengths are very long. - Stuart -

Soundman2020 wrote:

So no other rooms in the building have windows in them? There are no doors to the outside?

I understand what you mean. Sure there are windows at this side. No doors though. But since there is almost nobody else in this building I don't think that its neccessary. At least not yet. Even then sound would have to travel through the windows, outside air and through windows again. And not one single room with windows to this side is currently in use. Regarding your suggestion to take out the windows and bricking up the gaps.... The windows are approx. 40 cm built into the wall. Wouldn't that leave me enough space to double them? This should improve isolation and I'd still have daylight inside which I am really looking forward to. Thanks for your help and clarification so far. Best regards Daniel