Project studio in basement

Hi to all! First I have to say that I'm really impressed about the concentration of knowledge on that website. I've been sunken into the recording manual for weeks now and tried to soak like a sponge. I'm a guy from Austria (so also an Aussie, but without any kangaroos here :lol: ) and I plan to build a project studio into a part of the basement of my house. Please excuse if my English isn't always alright. I followed all your suggestions in the "read before post" section but I still declare myself as a Newby although I've already learned a lot! But now to my project plans! General details: - My budget is a max of 20.000€ (approx. 27.000 US Dollars) for building (no equipment included) the whole thing. - I have no problem with traffic noise or strange neighbours, so nothing to mind about that for acoustical isolation, but I live in the house with my wife and two childs and I neither want to be bound to the bed times of the childs, nor do I want to disturb my family when working in the studio or playing drums myself. Sound pressure details: - I will be using two Mackie HRM-824 MK2 nearfield monitors for rehearsal (at a level of nominal 85dBc - 95dBc). But sometimes I will also check the "low-end" :twisted: - Due to the fact that I play drums myself, I will use the rooms for practising too (110dBc to 130dBc ?) Current footprint details: - The current footprint of the room is shown in file "Current footprint.pdf" Unfortunately I'm not already used to sketch up, so I had to draw it in AutoCAD, where I had the only possibility to print to PDF (all other exports were unreadable). I hope that does not matter. All measurements are in centimeters. - At the moment, the room is separated by a brick wall, which already has a "hole" for a window in it and a door connecting the two rooms. It was thought as a separation of control and tracking room at the time of building, but so far I were not able to make a suitable footprint layout with that wall. I am willing to pull it down if it supports a better footprint layout. It does not carry any load (ceiling, etc.), so it can be easily removed. - There are two doors (normal non solid wooden doors used in houses) on the eastern wall, but I could remove one of them (and fill the hole with bricks) if it supports a better footprint layout. - There are two windows (double isolated glass) on the western wall, which can't be removed. But in the worst case when I can't reach an appropriate isolation of the studio rooms by adding a openable windows in the wall, I'm willing to work without daylight. The best thing would be to have the advantage of fresh air and daylight from the existing windows. - The materials and structure of the floor, ceiling, and walls are also shown in the footprint file. - The physical structure and measurement of the room bottom up is shown in "structure.pdf" - I have to explain the two air outlets in the ceiling: My house is a relatively new built one and has something that's called "Controlled living room ventilation" if I translate it word by word. A blower delivers fresh air from outside through a heat exchanger and soaks old air from inside the house where it also passes the heat exchanger. The so warmed fresh air is distributed into each room in the house via 10cm diameter tubing. Because my room currently is separated by a brick wall (shown in "Current footprint"), I have two outlets on the ceiling. I would like to use them for the ventilation of the studio rooms, but I have to do some sort of acoustical isolation. Target footprint details: - The studio shall at least consist of a control/mixing room, a tracking room and a drum booth (I play drums myself, so it will also be used as my practise room) - It would be nice when tracking room and drum booth could be turned into a nearly one room footprint (for example by dividing them with a sliding door) - I tried two different layouts (only schematics, therefore without measurements). "Destination footprint 1.pdf" is John's Corner Studio adapted to my room dimension and "Destination footprint 2.pdf" is another try to get rid of the small area I have. To clarify the wall structure I have currently in mind to build: concrete wall -> 5cm air gap -> 2cm glass wool -> double layer gypsum (12mm & 16mm) -> 10cm timber frame (filled with RockWool) Same will be done for ceilings. Walls will be placed on 1cm neoprene stripes (when floor is not floated) and sealed. If floor has to be floated, then 5cm timber frame on neoprene (filled with RockWool) -> 2 layers of particle board -> laminate floor (or carpet). ----------------------------------------- Question Section ----------------------------------------- 1.) Is there a real chance to cover my needs on the rooms physical dimensions? 2.) Do I have to float the floor as well to reach the needed acoustical isolation or is it enough to build a room-in-room (with its own ceiling) on the already existing floation screed? 3.) Unfortunately I didn't find the STC rating of John's inside-out wall here. What will it be when everything is sealed to air-tight? Will I reach the acoustical isolation with it to not disturb my family? 4.) Am I right, that each room must have it's own ceiling (and floor if I have to float it as well)? 5.) Am I right, that each wall to wall joint must be flexible? (for example rubber pads between and sealed with acoustical caulk) 6.) Am I right, that the outer insulation (the one on the gypsum situated to the concrete wall) must have a low density (e.g. 20kg / m³) whilst the inner one must have a higher one (e.g. 60kg / m³) 7.) Can I use the air outlets for room ventilation? 8.) How can I build a silencer to distribute one outlet on two studio rooms, without distribution sound waves between the studio rooms and the rest of the house? 9.) How is it connected to the rooms without breaking the acoustical seal (structure-borne sound)? So far, the above questions came to my mind whilst reading the reference section, recording manual and other posts. I would be very glad if you could help me with my project! I hope I provided as much details as you need. When not, just tell me and I will provide it! Thanks a lot to John for creating this site. I love it! Best regards, Edi (I just put this one here -> :horse: <- for all the dumb (recurrent) questions I may have asked. Just imagine I'm the horse! :shock: )

We can handle specific questions but multiple questions suggest that you have not read near as much as you will have to in order to get to a point were you ask, specific questions ;) EDIT: Call me a glutton for punishment: "3.) Unfortunately I didn't find the STC rating of John's inside-out wall here." A walls rating on the STC point system is dependant on the products that it is made of. The inside out wall is not a static building appliance. It can have 2X4 wood framing or 2X6 wood framing and in some cases it can have metal framing. It can have a 16 inch layout or a 24 inch layout. The panels could be 1/2 inch, 5/8inch it could be either of those X2 or it could be a variation of the three. Specific questions get specific answers...you have to know what it is you are going for, in a very educated method, in order for any one to make an educated guess. That said, the STC rating on John's inside-out wall can go anywhere from 20 to 47 (by it's self), 40 to 60ish in the proper assembly, the transmission loss will increase with the higher STC rating often but the LF has been known to suffer >if< the air space is particularly small due to a rigid air spring. If that doesn't help, I am not surprised :) It didn't help me the first time I read something similar either.

Adding to what xSpace already said...

- Due to the fact that I play drums myself, I will use the rooms for practising too (110dBc to 130dBc ?)

130 dB(C) :shock: !!! :!: That would make you the loudest drummer on the entire planet! 130 dB(C) is roughly the loudest sound you can expect to get from a large tower of speakers at a rock concert, measured 1 meter away. As a drummer, you might well be putting out 115 dB(C), but I totally doubt you will ever managed to get 130 dB(C) out of drum kit (unless maybe you put a stick of dynamite inside it...). At 130 dB(C) you'd be in pain over most of your body, and you'd suffer irreversible hearing damage in about 22 seconds. Give or take a second or two...

I would like to use them for the ventilation of the studio rooms, but I have to do some sort of acoustical isolation.

Search the forum for "silencer" and you will find a lot of information on how to do that.

concrete wall -> 5cm air gap ->

5cm is very thin for your air gap. It should be at least 10cm, preferably more.

2cm glass wool ->

2 cm fiberglass is also nowhere near enough. You should fill the entire cavity between the outer leaf and inner leaf.

double layer gypsum (12mm & 16mm)

Forget the thin (12mm) drywall. Use only 16mm. Also consider using Green Glue in between the layers.

-> 10cm timber frame

so you are planning to build inside-out walls? Good!

If floor has to be floated, then 5cm timber frame on neoprene (filled with RockWool) -> 2 layers of particle board -> laminate floor (or carpet).

Read this: viewtopic.php?f=2&t=8173 As you can see, what you propose for "floating" your floor simply will not work. Wast of time, money, space, and will most likely make things worse, not better.

3.) Unfortunately I didn't find the STC rating of John's inside-out wall here. What will it be when everything is sealed to air-tight?

Like Brien said: That all depends on how you build it! Build it wrong, you will only get maybe STC-30 out of it. Build it right and you can get well over STC-60. By the way, STC is a lousy way of specifying isolation for studios: it tells you nothing at all about low frequency isolation, which is where all your problems will be.

4.) Am I right, that each room must have it's own ceiling

Yes, if you want good isolation. And each ceiling must rest ONLY on its own inner-leaf walls, NOT touching any outer leaf walls at all, nor the outer-leaf ceiling.

6.) Am I right, that the outer insulation (the one on the gypsum situated to the concrete wall) must have a low density (e.g. 20kg / m³) whilst the inner one must have a higher one (e.g. 60kg / m³)

No. Use 48 kg/m3 in the cavity, and whatever density is needed for each type of treatment inside the room, which might or might not be the 48, or 20. But 60 is probably too high.

8.) How can I build a silencer to distribute one outlet on two studio rooms, without distribution sound waves between the studio rooms and the rest of the house?

With very long, very convoluted ducting, with multiple 90° bends and duct liner on the inside! It would be much easier and cheaper to build two separate silencers, one for each room outlet. And another two separate silencers, one for each room inlet. Four in total. Or rather, six in total, since you have three rooms, not two. I think your "footprint 2" looks like a good start, except that I think you are wasting space with the soundlock. Maybe if you were to move your CR to the middle, so that the main door is in the middle of your CR rear wall, you'd be able to put your live room on one side and your drum booth on the other. - Stuart -

Hi Stuart! Thanks for your reply.

130 dB(C) !!! That would make you the loudest drummer on the entire planet! 130 dB(C) is roughly the loudest sound you can expect to get from a large tower of speakers at a rock concert, measured 1 meter away.

That's the reason why I wrote 130dBC with a question mark. I will immediately throw my SPL meter away.

You should fill the entire cavity between the outer leaf and inner leaf.

So when the concrete wall is the outer leaf and the gypsum is the inner leaf, I should fill the whole space between with insulation? Will this still count as an air-gap?

Forget the thin (12mm) drywall. Use only 16mm.

I understand, that using only 16mm will create a leaf with a higher mass, but shouldn't each layer of one leaf have a different density, because of the weak-spot at the resonance frequency?

Also consider using Green Glue in between the layers.

What is "Green Glue"? Could you explain it or name a manufacturer? I don't know what I have to search for here in Austria.

I think your "footprint 2" looks like a good start, except that I think you are wasting space with the soundlock. Maybe if you were to move your CR to the middle, so that the main door is in the middle of your CR rear wall, you'd be able to put your live room on one side and your drum booth on the other.

The reason I would prefer drum booth and live room on one side is that I would like to be able to open the doors to the drum booth, so you can make one room out of the two (not for recording, but for band practice). If you have an other suggestion for a better footprint where drumbooth and live room is on one side, please tell me! I don't stick with the soundlock! One problem I see myself on the "live/drum-booth to practise room" concept is, that the isolation between studio rooms and rest of the house will only work when the doors are closed between drum-booth and live-room. When both rooms would have a common floor and ceiling, the isolation to the rest of the house would work regardless if the door is open, but I'm afraid, that would ruin isolation between live-room and drum-booth when recording. (I hope it is understandable what I mean). Do you have a suggestion how this can be resolved? I will go into more research about building techniques, wall structure, etc. later, but first I have to be sure about the footprint. To all of you: I'm really sorry if I wasted someone's time with imprudent questions in my first post. I will now have a look at the project step by step. So when I'm finished with the layout (where I'm still happy if I could get some suggestions), I will come back with some detailed drawings for discussion. Best regards, Edi

"but shouldn't each layer of one leaf have a different density, " In theory. Refraction (changing the direction of travel) is what is being thought of when layers of different density are suggested. Since it is two fold, small in how it helps us and adds an un-needed level of difficulty in trying to establish just how it helps us, it is most always recommended to just use the amount of mass required to reach your isolation goal.

So when the concrete wall is the outer leaf and the gypsum is the inner leaf, I should fill the whole space between with insulation? Will this still count as an air-gap?

For any MSM you need to fill the air gap with insulation, not just concrete and drywall. If you do not fill the air with insulation, you could be losing anywhere up to about 16 dB of isolation. The insulation serves several purposes, but mostly it forces down the resonant frequency of the MSM system, and damps resonance in the cavity. Without it, the cavity itself resonates, and the MSM frequency stays high, both of which reduce isolation. Don't think of it as an air-gap (although it is often called just that). Technically, the "gap" between the leaves is a damped spring. The air is the spring, and the insulation is the damping. That's why the more correct term for this type of wall is MSM (mass-spring-mass) rather than MAM (mass-air-mass).

What is "Green Glue"? Could you explain it or name a manufacturer? I don't know what I have to search for here in Austria.

It is made by the "Green Glue" company http://www.greengluecompany.com/index.php Despite the name it is NOT actually glue: it never dries. It's only purpose is to create a damping layer inside the wall, between the layers of drywall, which greatly increases isolation in the low frequency region. There are no substitutes. This is the only company that makes it and also provide independent laboratory test reports. A couple of other companies claim to make something similar, but they never seem to be able to provide any independent technical data on their products... It is expensive, but well worth the cost when you need excellent isolation in low frequencies. which is what you will need for your drums. Call them or e-mail them to find out about distribution in Austria. - Stuart -

Edi_28 wrote:

Forget the thin (12mm) drywall. Use only 16mm.

I understand, that using only 16mm will create a leaf with a higher mass, but shouldn't each layer of one leaf have a different density, because of the weak-spot at the resonance frequency?

With studio sound isolation, the controling factor is low frequency isolation. A wall that isolates lows effectively has such high isolation at high frequencies that the dip in isolation is not significant. Andre

OK! What I've learned so far is, that I have to do my homework first. I've read several very interesting threads on this board, that will bring me on the right track and I understand now why building a studio is 90% planning and only 10% constructio. I will come back to when my plans have got so much details, that I'm able to ask detailed questions. My greatest "Thank you" to all of you which guided me to the right way so far. Is it better to create a new subject when coming back, or shall I just update this one? Edi

Edi_28 wrote:

What I've learned so far is, that I have to do my homework first. I will come back to when my plans have got so much details, that I'm able to ask detailed questions. My greatest "Thank you" to all of you which guided me to the right way so far. Is it better to create a new subject when coming back, or shall I just update this one?

Most of here learned by asling questions. Do not stop from asking (lots of) questions. We love people that want to do things right and helping them. If you follow and learn from the answers to your questions, you will end up with the best possible studio for your needs and limits. As you already learned, the long part is the design, and learning the factors involved in it. For right now, it is probably better to ask questions of separate issues in separate subjects. We are looking forward to your questions! Andre

Thanks Andre for your encouragement! I won't stop asking, because I know that my design would have a lot of failures in it without the people around here, and I definitly want to do it right! I'm very impressed of some, how fast they turned from a newby to an expert (e.g. Soundman) just by reading and trying, so I try to follow their bumpy road of self education. (Read it - Try to understand - Learn it - Use it) Currently I have to get sure about the footprint, of how I can fit my needs into that room whilst dealing with existing doors, windows, and so on. So I'm looking forward to get some response when my plans reach the status to be postable. As soon as I have found a footprint I'm happy with, I will come back with more detailed plans to hopefully get some help and much more important, to get some criticism. (I also must do some sketchup training too.) Needless to say, any recommendations are always welcome! Edi

One problem you are going to run into when trying to put so many rooms into a small area are the >doors< required to access each room. Pretty much every room you have in your PDF drawing, excluding one, will require doors coming from the control room...what a pain :) Bigger rooms are in your future.

I know that this is a problem, so I'm currenlty in heavy research for another layout to solve it. If you have any suggestions, you are welcome. Another problem I have is the following: As far as I understood, the cavity between two leafs must be sealed airtight. So if the cavity surrounding the new rooms has to be airtight, I have to put a second sealed door in front of the existing one, because those are doors like you use it in a living room which are modified in that way, that an airflow can happen between the air outlets in the studio room (blowers) and other outlets in other rooms of the house (suckers). So my idea currently is to remove the one door in the south (close it with bricks and render) and to build a small room surrounding the remaining door and seal it airtight. Inside the small room I plan to mount all exhaust air silencers from the studio rooms, so that the vent will still work. I have done a real simple drawing in paint (because currently I have no other possibility to do it in a better prog). I hope it is understandable. Next to the outside of the small rooms will be the other "inside-out" walls of the studio rooms.