New studio for foley / sound for movie

Hi I am based in Viet Nam and am about to build a studio area that will be used to mix and record some foley sounds and voice over for independent films. The maximum size that we have available is: length = 6.4 m x width = 2.66m x height = 3.5m . (Outside measurements) This is to be built inside an existing room. We need to include a corridor on one side in order to reach the back of the building. There will be a reception area at the front of about 5m. X 4m. (see attachment below) There is a fairly busy road 4m in front of the building and a very quiet river to the back. Both sides of the house are occupied, one is a car wash and the other residential. Upstairs we plan to build a photo studio / green screen for some filming. I had to start somewhere so I ran some numbers using the mode calculator from realtraps.com. The largest room with recomended ratios that I could fit into this space was: 3.98m x 3.15m 2.5m (about!) This reverses the width and height measurement in the realtraps program, I assume this doesnt matter regarding acoustic characteristics of the space? So the plan at the moment is to create 2 rooms: 1.control room with inside measurements of 3.98m x 3.15m x 2.5m. Then treat with home made bass traps – at the sides and above the listening possition,and in each corner. Not sure how we would change the height from 3.5 to 3.15m – not even sure that it would make a difference? 2.A folley recording / vocal booth with 1 one wall along the corridor made up of 2 layers of bricks, 3cm space then a metal frame (is wood better?) filled with 10cm of rockwool all covered in fabric. The other walls would be one brick wide with 10cm of rockwool as before. The folley /ADR room would then have internal measurements of about 2.2 m x 2.2m x 3.5m and there would be a small double window between the two rooms (one of the pieces of glass at an angle). We would raise the floor of the ADR/vocal booth(wooden boards above rockwool. The floor has to be raised as the Vietnamese talent is rather short and the control 24 + monitor is rather high to look over! We would add a rug if needed. There would be a monitor for the talent to view in the room and one door made from mdf/rockwool and covered in carpet. Equipment in control room will be: Mackie HR824 Digidesign Control 24 desk (this has a large footprint and is rather high at the back) I have an sE reflexion filter The desk is already made with room for our rack gear and the control 24 (from my old studio) We plan on building a false wall from gypsum board with rockwool behing it to house our 2 monitor speakers so that they are flush with the front of the control room. We are planning on a 1.5 x 60cm viewing window (2 layers of glass) All outside walls are brick covered with cement./plaster. We would get some custom doors made. Would this work? Do ratios really make a difference at this small size? Any better solutions / obvious mistakes. We do not have the ability to purchase any off the shelf solutions in Viet Nam, just rockwool, gypsum board. Hope you can help! Mike

what is the ceiling structure?

The quietest recording studios are for Foley work. The reason being that the recorded sounds are amplified well above their original levels, also raising the background noise level in playback. Without further details, I would STRONGLY SUGGEST double 100 mm brick walls and equivalent ceiling for sound isolation at a minimum. Air conditioning/ventilation will will require dramatic efforts also, or an interconnect to the recording system turning it off when recording and testing sounds. Andre

Thanks for the replies. The ceiling is concrete. Approx 2 bricks thick. The outside walls are one brick thick with plaster. Our outside wall is approx 1-4 cm away from next door. However, the walls may touch as the houses are not always straight!

you probably need to do some testing to determine how much structural transfer you have. a small ball peen hammer and a rubber mallet to do some tapping tests to determine how much is making its way into your neighbors homes (and vice versa). you'll need an assistant to do the tapping and a note pad and and the cooperation of the neighbors. but once you determine if you have any significant transfer via the building structure, you can determine just how much you'll need to do to fix it and building your inner shell to prevent it from being a major issue.

Thanks for the idea Glenn. I will give that a go tomorrow. Do you think the general idea for the layout is reasonable? We would also like to record a few singers in the booth as well as make a rough mix for movies. Are we expecting too much in this space? We will give the ceiling a good thump as well to see what can be heard through that. Mike

i think the layout in general is ok. but there will be a lot more detail needed to create the proper isolation assemblies and treatments given the small space.

So from upstairs there is very little noise from tapping with a hammer, even with ears close to the ceiling. We will be putting in a false ceiling with rockwool in the studio to run some cables through and pipes for AC. So there should be no noise from above. From next door you can hear the ball peen hammer when close to the wall. You cant hear the rubber hammer. It is too noisy from outside to really tell how much noise gets through as there is no front to the building at the moment, apart from an electric security shutter. The car wash as described in a previous post is actually one shop away, my poor memory! There are actually shops either side of us that are shut down in the evening and are very quiet during the day. The reception area will be between the control room and the outside world, this will have a glass door to the road. At the moment we are planning on two layers of bricks between the control room and reception.

last step might be to use a contact / proximity mic on the floor and walls and record the noise levels just to see what frequencies are coming though. if it's infrasonic, then you could probably just cut that with EQ. if it's higher, then it might be problematic as Andre has pointed out. http://en.wikipedia.org/wiki/Infrasound

Ok Thanks. As suggested by Andre, we are going to build 2 layers of brick (20cm) around the whole studio (thanks Andre), This will be plastered smooth. We will complete the shell and make the doors. We will then check noise levels as you suggest Glenn. I cant see how we can measure sound levels before we build the main inner shell. We will then have to sacrifice space to add rockwool / gypsum board etc if needed. Does this seem reasonable? Mike

Yes, some space will be consumed by the treatments... If you have enough space overhead, you can use that to preserve floor space. The only reason I suggest measuring Now is so you have some idea about what ever low end rumble you may have to address.

gullfo wrote:

The only reason I suggest measuring Now is so you have some idea about what ever low end rumble you may have to address.

Glenn is being very modest here. IF you do not address your ambient sound levels in your foley isolation, the room will be a failure. Andre

Thanks Andre/Glenn We will certainly take the advice from this forum and test the sound levels as suggested. We have no choice on the materials and size of the first 'shell' So we have started to build this with two layers of bricks as suggested. We will then treat the room as necessary. We do have a lot of room above to heavily treat and we will need to raise the floor at least 30cm so that the talent can see through the viewing window. If we have to build another inner wall as well and then so be it. I will post the results of testing ASAP Mike Photos of the wonderful brick laying below - this was the best bricky we could get!

I am interested to hear how your build works out. I may build a similar Foley stage out of double brick and we are also next to street/shops.

There is a fairly busy road 4m in front of the building

"Busy road" implies low frequency vibration from traffic. So how are you going to isolate the floor down to the level you'll need for a Foley studio? And even more, how are you going to do that now that the inner-leaf walls are already being built? :shock: And how are you going to seal up that roller door in your picture, in order to make it into a usable outer-leaf? More bricks? Is there another entrance to the building? - Stuart -

Hi Stuart The road is mainly motorbikes and is a big concern for us. The roller door is only a security measure. We are putting in some inner doors just behind it that will form the "shop front". The busy road is the control room side. The Foley recording room is behind that and we were going to isolate that with a new floor - we have over 3.5 m of height to play with. The walls being built at the moment in the recording room are our outer walls. We were thinking of building any treatment needed inside of them including an inner leaf (if needed). (If needed) we can build another wall in the reception area between the control room and roller door. If rumble is a problem in the control room then we will either have to build an inner leaf (not much space to play with) or use headphones for some critical mix decisioned (not great) or ???. I am only one of the partners in this build and it is going a bit quick for my liking. I am trying to get the most information I can and as soon as possible in order to keep up! The way the others see it is that we are already in a better position than many other Foley studios in town. We even have an earth which is unheard of! Mike

For your benefit, please stop construction until the entire design is complete. Study my sig line! Andre

OK! I made a recording of the noise from the road end of the studio where our outer door would be. I put a Zoom recorder on the floor and recorded an average and peak reading of the frequencies over about 1 minute (this is all I could get hold of for this test) Graph below: The SPL for the outside background noise (A weighted reading) peaks at 82dB and is steady around 73dB standing 4m from the road. I want this to work! Are these tests any use and are there others I can do with simple equipment? For what its worth, I did a similar test in the control room area where the listen position would. The meter was mainly fluctuating around 66dB (I suspect because a lot of the horn noise had been absorbed/reflected). We have stopped the build with the two layers of bricks (22cm). We haven't made any changes to the floor, ceiling or made any doors, viewing window yet. We need to be able to record 3 people at once in the voice over/Folley room so that's a limiting factor on size. We can create another wall betwwen the control room and road (this is going to be a reception area, however, I recon I can persuade my partners to allow me 5-10 cm or so. We havent decided on the front door. There is no through access to the back as this is a river side property. There is very little noise from the back Mike

Hi These are some more detailed drawings of the rooms. We plan on two doors. One sliding door and one door made from mdf and rockwool. The windows will be two double glazed windows, one built in the control room and the other in the "floated" Foley wall. Any comments most welcomed!

what type of audio monitors are you using? the window in the CR seems too high compared to the audio monitors. also the floating floor is going to be bad at low frequency. for the foley room (at least) i'd suggest a heavier floor - like concrete on springs and then float the entire inner floor on that floor. otherwise another option is to float the walls and ceiling as an assembly on neoprene pads, and then for the floor use: 2" 60Kg/m3 rigid insulation on the floor + 12mm MDF + 12mm concrete board + 12mm MDF + 12mm engineered wood or whatever you like. see Rod's 2nd edition book on details around this idea.

Thanks again!

gullfo wrote:

what type of audio monitors are you using?

I am using Mackie 824's

gullfo wrote:

the window in the CR seems too high compared to the audio monitors.

The window is high. However I have a Digidesign, control 24. This desk is very high at the back - I then have my monitor on top of this. From floor to the top of the monitor is about 1.4m.

gullfo wrote:

also the floating floor is going to be bad at low frequency. for the foley room (at least) i'd suggest a heavier floor - like concrete on springs and then float the entire inner floor on that floor. otherwise another option is to float the walls and ceiling as an assembly on neoprene pads, and then for the floor use: 2" 60Kg/m3 rigid insulation on the floor + 12mm MDF + 12mm concrete board + 12mm MDF + 12mm engineered wood or whatever you like. see Rod's 2nd edition book on details around this idea.

Thanks for the floor info. I'm not sure I will be able to make the concrete floor on springs. The second option seems possible. I will see if I can find concrete board. I have the Alton Everest Master Handbook and his sound studio construction books. Sorry Rod but I cannot buy your book here in Viet Nam. I will order, but It will be too late for this studio build.

I see many, many issues with your isolation design. There is no way you are going to get the level of isolation you need for a Foley studio like that: I'll echo what Andre already said: STOP! Don't build anything more. Take the time to understand the principles of isolation and acoustics here, then re-design the studio using those principles. What you are showing in those drawings, and in the photos, is just not going to do what you hope it will do. Just a few of the issues I noticed: - Your walls are not decoupled, and will not isolate. - Your ceiling is not decoupled, and will not isolate. - You have incomplete and unsuitable treatment in the LR - You seem to have multi-leaf construction in some places. - Your window plans are incomplete and questionable. - Your door plans are incomplete and questionable. - Your speaker soffits are a disaster, and will likely make things worse, not better. - Your plan for floating the floor is unsuitable for ANY studio, let alone for a Foley studio! - The structural members are woefully inadequate for supporting the amount of mass you need. - The size of the Foley room itself is minute. - There are no details regarding the HVAC system, which is a key element in a Foley studio There might be more too, but after seeing those basic ones, I didn't bother looking any further. - Stuart -

Thanks again for the feedback. Floor: Ok, I think I have made the changes to the floor as suggested by Glenn. Is this better now? I wasnt sure how to cover the rockwool at the edges between the wall and floor - I have added some material to do this. A picture in the Alton Everest book shows wooden strapping underneath the floor, but not touching the concrete underneath - I have read this as a frame to attach the mdf too. Is this correct? (see picture) Walls: The walls are to be floated on neoprene as suggested by Glenn. The wall frame will be reinforced with metal as necessary. Is an inner wall of 5cm with a 1 inch air gap thick enough?, we have little space? We would add another 5cm to this inner wall in the voice over room only. This would be covered in fabric. I know this is far from ideal. However, I am under the impression that this is the only way to make it usable (ie dead). The same would be done on to the voice over ceiling. HVAC The AC will be of the split type but will be turned off for recording / critical mixing. We will build a box around it similar to a design in Alton Everest's book. Doors Windows The doors and windows are yet to be designed. I need to check I am on the right track with the walls etc then I will try and find a suitable window/door design. There is a lot of pressure to get this done yesterday as we have a film to release in April! This is Viet Nam and it is just the way it is! If the room isn't usable for Foley then so be it. We can use it for voice over. I am aware that there should be a Mass air mass construction and we would have a Mass Air Mass Air Mass construction between the control room and voice over room. Is this the first disaster or is it usable? I could ask for the brick wall between the control room and Voice over room to be removed if it is a must. We have no space for a double swing door type arrangement. So we were thinking of one sliding door in the corridor and one door of mdf filled with 10cm rockwool Treatment We are thinking of building a bass trap for the back of the room (although space is tight) and treating first reflections with 10cm rockwool 2cm from walls Room size - There is nothing I can do about this. It is too small! This is the room available. I need to try and make it as usable as possible. I am hoping an inner wall of 5cm rockwool + 2 layers of gypsum will make it usable. I really appreciate the help. I appologize if I am making the usual mistakes, already covered in this forum, but I am trying to learn as quickly as possible on top of trying to find the materials/translate into Vietnamese and keep the partners happy - they want to build the reception etc and cant start until the inner walls/doors etc are in place. Mike

you don't need under the sleepers on the foley floor. just put the floor layers on top of the insulation - this is possible since the walls are separate. also consider the use of GreenGlue in the floor and wall layers to add some additional LF isolation.

Ok Thanks Glenn. I will remove the wooden sleepers. The rockwool here is far from rigid . When fitted the floor will be stable? I thought another reason for the sleepers in a similar design that I saw was to keep the floor a bit steadier. I have contacted greenglue to see if they have any distribution over here. Is the brick wall between the control room and voice over room (the extra leaf) going to be a big problem? (other than working out how to build the viewing window and the wasted 10cm of space). Is the design below a possibility? I know we no longer have a wall within a wall arrangement in this control room design but do you think it will be any use. The options as I see them are getting the brick wall taken down. (Wont go down too well!) Going with the 3 leaf Mass Air Mass Air Mass arrangement Making the compromise below: