Isolation and treatment for a noisy downtown studio

Hello everyone, First I want to say thanks for this great learning resource. I have been searching the forum looking for instructions to what I need, but I couldn't seem to find it, so I thought I should post. I have an already constructed room that I will be using for various film and video shoots, of course we will need to pick up sound as well. We are located in downtown cairo which is unfortunatley extremely noisy because of heavy traffic (mainly car horns and buses and what not). The room is already built, so I only have the option of modifying what is already there. The walls are made of red brick (i think those are made of clay), the room's long end is 15 meters, the shorter end is around 9 meters and the ceiling is a little bit less than 3 meters high. I need to isolate the outside noise so that our mics don't pick up the street noise anymore, this is my biggest priority, but after that I need to also do some acoustic treatment because as is the room sounds strange, not sure what you guys call it exactly but it has some sort of echo. I will spend what is needed, but of course I still would love it if there are cheap, effective options. Thanks in advance for any info you provide. :)

Hi Mokamal, and welcome.

I need to isolate the outside noise so that our mics don't pick up the street noise anymore, this is my biggest priority, but after that I need to also do some acoustic treatment because as is the room sounds strange, not sure what you guys call it exactly but it has some sort of echo.

Do you have a sound level meter? If not, then get one. You need to measure the real levels, in a few places outside your room, on a very noisy day. Use the "C" scale, and "slow" response on the meter. Measure at several times, in several places outside the room, all four sides, even up on the roof if you can, to get the best idea of how loud it really is, with real numbers. Then do the same INSIDE the room, with all the doors and windows closed, to get an idea of how much isolation you already have with the existing structure. From what you say, it seems that sound getting out of your room and disturbing your neighbors will not really be a problem! OK, since street noise is your big problem, in addition to getting plain dB SPL readings, I'd suggest that you need to also figure out what part of the spectrum you have the worst problems with. My guess is that it will be the low-frequency general rumble from traffic, plus engine noise from heavy vehicles (trucks, buses, etc.). You need a spectrum analyzer or acoustic measurement software like ETF to measure that accurately. Once you have those numbers / graphs, then you can figure out how much isolation you need, and then figure out what kind of construction you will have to do to obtain it. What is the floor made of? And what about the roof? - Stuart -

Huge! That is a lot of space! I didn't have anything to add except WOW!!!

Hi guys and thanks for replying. Soundman2020: My floors are 2 inches thick pinewood on top of sand on top of concrete, and the ceilings are red brick.( although I have a lighting grid on the ceiling, so I would not want to touch that, if possible) I know that your suggestion to measure the noise is the best way to go, but I am in a position right now where I am losing money as time passes because I am behind on a project and I absolutely need to finish up this studio. I appologize for posting here at the last minute, but because of time issues and because doing things by the book would mean that I would have to get some outside help, I would rather just do overkill isolation where I would be safe and go far over what is needed than to carefully measure things and do it precisely. do you think you can help me do this? From what I could gather here on the forum, a double leaf brick wall would be the best way to go, do you agree? I have a lot of space and do not mind to lose some of it in order to have a quiet shooting space. What do you think?

I know that your suggestion to measure the noise is the best way to go, but I am in a position right now where I am losing money as time passes because I am behind on a project and I absolutely need to finish up this studio.

I don't think it would take more than a couple of hours to do the test I outlined. I don't think it would be hard to find a sound level meter in Egypt. If you don't want to do what is necessary, then I guess it just isn't very important to you to get good results.

but because of time issues and because doing things by the book would mean that I would have to get some outside help,

I'm not sure I understand what you mean by that. In order to over-build it, you will need even MORE outside help than if you were to do it right, "by the book". Especially if you are on a deadline.

I would rather just do overkill isolation where I would be safe and go far over what is needed than to carefully measure things and do it precisely.

Even if you do over-build to the extreme, you sill STILL need to "carefully measure things and do it precisely.". You can't build a studio and expect decent results with lousy workmanship, no matter how much "overkill" you build into it. But anyway, if you really do want overkill, considering what you told us already (very noisy very busy street right outside), then I'd start by ripping out that floor, all the way down to bare earth, and pouring a brand new, totally decoupled 10 inch high density reinforced concrete slab, and build 10-inch concrete walls on top of that, decoupled from the outside walls, then pour a 10-inch concrete ceiling supported on very large steel I-beams and steel plate, with a 10-inch air gap all around (walls and ceiling) filled with rock wool. No windows. For the door, use two of Rod's superdoors back-to-back, with very thick sheet lead in the core, and five seals each, instead of three, with an airlock in between. That's about the only type of overkill construction I can think of that is guaranteed to give you really excellent isolation from practically every conceivable noise, except maybe a ton of TNT exploding next door.

a double leaf brick wall would be the best way to go, do you agree?

No. Yes. Maybe. It all depends on what you need, and how well you build it. can you guarantee that the builders will not spill any mortar in the gap between the inner leaf and outer leaf? That they will work perfectly, and leave the air gap absolutely spotlessly clean, with no bridging that would cause flanking?

the point is people can not help you if they do not know what you need. Remember, if you build it wrong, you will have no business and will have to rebuild. It is a lot cheaper to do it right the first time. If you are in a rush, make an accurate detailed drawing and post it here. Give it a couple of days for comments from people here and then call John for paid consultation. He will have had a chance see you drawings and you can talk effectively. Andre

Hello Soundman2020, Thanks for the info, and like I said before, I was not doubting your advice, I just did not understand the process. I'll see what I can do about testing. Please check back here in a day or two, I really appreciate your help. And AVare thank you as well, I will try to post a better drawing at the same time as the test results.

Hello again, We found a better place that we will probably going to use, the new space is bigger andin a much better area of town. It will take us some time though before we can actually get in there and start construction. So I thought I should pop in and say thank you to both of you for the offered help, if everything goes as planned and I still need help, I will post a new thread, if not, then hopefully I will still talk to you around the forum.