Hello there friends, this is an update of the Garage Studioi project's status. The project, as it was concieved and designed so far, is officially buried. Goverment laws put the last nails on the project's coffin... :cry:
I went to the goverment agency to ask for details of getting a license for the studio and they stated that every business based on an underground floor should have a minimum of 4m (12f) floor to ceiling height. :shock:
I have only 3m (9f) of height (floor slab to ceiling slab)... :cry:
I'm never gonna get a license and I'm never gonna get paid for renting the facility to other musicians. I'm never gonna get my money invested on the project back (not that I was expecting to but I hoped at least to have a small income to cover my monthly expenses :roll: ).
So, I have two choices: forget all about this project and continue to spend my time in that shithole (excuse my language) that we (me and my band) call studio or modify this project to suit MY and my band's needs.
I decided to go with the second choise. Playing drums and having music in my life kept me going through some very hard shit (excuse my language again) and I owe them that much. I owe it to myself...
So, considering all the above, I took a shot designing my personal studio on the space my brother offered me (pics and sketchup file below).
This is a CR - LR configuration, including a small area for the main entrance and for a kitchen/WC. CR coverage is 16,5m2 and LR coverage is 25,5m2 (acoustic treatment is not included). I tried to stay as far as possible away from the south part of the basement, to keep my distance from the lift/boiler/pumps noise.
For wall construction, check my previous design, nothing's changed about that. When we finish building the two floor basements and take some sound measurements, I will modify the wall's design accordingly.
There's no need for a window between the CR and LR anymore, I'm gonna have a video camera in the LR, recording our performance and a monitor in the CR displaying the video feed.
For the CR, I'm gonna have a pair of Genelec 1032A speakers and a 32" TV/monitor in soffits (I could have them on stands but I really want to build those soffits). On the back wall, superchunck bass traps on both corners and a slat resonator in the middle. Side walls will be covered with slat resonators. Floor will be pseudo-floated (from top to bottom: wooden floor parquet, a layer of plywood, a layer of drywall and rigid fiberglass or sand). Ceiling will be covered with two layers of drywall and insulation, with a cloud in the center of the room (wide enough to include the listening position).
For the LR, I'm thinking of superchunck bass traps on all four corners, slat resonators in between, a curved panel absorber to cover that bloody pier (and provide a bit of diffusion?) and two clouds on the left and right side of the room respectively. For floor and ceiling see the CR above.
Slat resonators will be tuned AFTER I finish building the rooms and sound measurements are taken. And they will be made removable for more absorbtion, if necessary.
That's all folks... Your feedback (flame or praise) is something that I always, eagerly, expect (and rarely get... :oops: ).
Respect,
John
Designing a recodring studio in an underground garage
Originally posted at johnlsayers.com, topic 10950.
You are getting damn good at sketchup John :)
I like the design, it uses the space available really well. My only suggestion would be to raise the front speakers so they sit over a glass window with full view into the studio.
Hi John! I hope the New Year has found you more healthy and more busy than ever! :D
Thanks! And I haven't even touched the Layer/Component functions yet... :wink:You are getting damn good at sketchup John :)
You saying that is like music in my ears man! Those piers gave me a hard time trying to place the rooms around them and I also had to stay away from my noisy neighbours (lift, boiler, water pumps) but I think it turned out pretty well at the end. Even my brother will be satisfied when he finds out that I left more than 30m2 of space available for those storage rooms we were planning to have... :)I like the design, it uses the space available really well.
John, I was ahead of you on this one man! :lol: More than a week ago, I left you a message on the MeowMix thread, asking you for details on raising the speakers above the windows! I was aiming for a corner CR at that time, having a full view of the LR with that bloody pier in the middle. But then, I got creamed by the 4m height rule and I decided that a window just doesn't worth the money and effort for just me and my band... A monitor and a video camera should be more than enough for us... I really appreciate your suggestion though... :wink: Best wishes, JohnMy only suggestion would be to raise the front speakers so they sit over a glass window with full view into the studio.
John - to create that glass system you have to cantilever the whole front section containing the speakers off the rafters supported by a beam.
here's a pic from Jon's 3D model. You can see the second beam is holding up the studio front wall skin.
Talking about getting good at sketchup... I feel a complete beginner seeing your 3D image John... :oops: I could see the beam holding the front wall and the soffits in place above the glass from the pics below. This construction looks very indimidating though, if you don't have detailed schematics and a professional to guide you... Lucky Jon... :wink:John - to create that glass system you have to cantilever the whole front section containing the speakers off the rafters supported by a beam. here's a pic from Jon's 3D model. You can see the second beam is holding up the studio front wall skin.
Since I'm sort of finalized my design (I've tried different orientations of the CR-LR rooms but with those piers getting in the way, I either get smaller rooms or get them too close to the noisy south of the basement) and with the day of construction still very far away, I decided to pay attention to the little details of the design, aka the walls' design and the soffit design. I'll begin with my walls, if you don't mind...
I knew from the beginning of this project that my main goal for isolation would be to keep the noise OUT of my studio rather than IN. And I know that, until I get some measurements of the sound levels I'm gonna get OUTSIDE of the studio from cars coming and going and from structure bourne noise and vibrations, I can't determine the actual level of isolation I'm gonna need. My (and from people's comments here) guess is, high levels of low frequency isolation would be a must (imagine a Harley Davidnson Fat Boy parking 1m (3f) outside my studio's wall and you'll get the picture... :shock: ).
Now, what makes a wall assembly efficient? Quoting Rod Gervais from his book "Home Recording Studio - Build It Like the Pros", page 36: "Every assembly essentially creates a panel that will have it's own center frequency... ...A resonant frequency will pass through a wall like a hot knife through butter... create assemblies with resonant frequencies below 10Hz..."
OK, first stop, Resonant Frequency. After a bit of searching I found the formula that calculates the resonant frequency of a double wall assembly (it was in one of the document that AVare throws out occasionaly :wink: , the NRCC-44692. After some formula substitutions (pages 4-5), the equation for
the mass-air-mass resonance of a double wall with it's air cavity filled with sound absorbing materiali is the following:
Fr=1900*sqrt((m1+m2)/(m1*m2*d)) where
Fr is the resonant frequency in Hz
1900 is the constant factor for a cavity filled with sound absorbing material
m1 is the mass of the first surface layer in kg/m2
m2 is the mass of the second surface layer in kg/m2
and d is the depth of the enclosed air cavity in mm
m1 and m2 actually denotes surface densities
In my design, I'm using two kinds of wall assemblies, concrete-air-drywall for the perimeter wall and drywall-air-drywall for the walls between rooms. Fortunately for me, I didn't have to search around for concrete blocks and drywall panels surface density values, there is a table on page 6 of the NRCC-44692 document showing the surface densities of wall materials including CB and GB.
In Greece, typical thickness of concrete blocks used is usually 150mm. Surface density for those is 116,25 kg/m2. Surface density of the typical 16mm gypsum board that is used here is 9,84 kg/m2. When I substitued these values to the above equation, having d, the air cavity, varied from 10mm to 200mm, the table attached below was formed. If it's too small to read, you can get a larger version HERE.
f(x, y) is the resonant frequency of the various combinations of assemblies I calculated with varying d. t is the overall thickness of that particular wall assembly in cm. For example, f(16, 32) is the resonant frequency of the wall assembly with a layer of 16mm drywall on one side and two 16mm layers of drywall on the other.
I have to get some office work done for tomorrow now :evil: , so, I'll leave it like this and come back later to continue this study. In the meantime, pleeease, tell me your opinion of this study and give me any comments based on the data showed in the table.
Thank you very much for your time and patience.
John
OK, where were we? Oh, yes, resonant frequency of a double wall assembly (I should have started with the soffits... :roll: ). Well, since noone offered any opinions on the calculated data, I'll give it a shot... :wink:
Let's start with the drywall-drywall assembly. No suprises here, frequency drops if we increase the mass on each panel or the cavity between them. Frequency drops from 270,9Hz to 60,6Hz for a single drywall layer on each frame, from 234,6Hz to 52,5Hz for a single drywall layer on one frame and two layers on the other and from 191,5Hz to 42,8Hz for two layers of drywall on each side. An interesting point here is that, if we decide to use a drywall-drywall wall assembly, we could have a 60,6Hz resonant frequency with a 23,2cm thick wall (single layer of drywall on each side) OR have the SAME frequency, DOUBLE the mass (that's gonna be helpful when we get to the frequency region controlled by Mass Law) with two layers of drywall on each side and 6,8cm thinner wall. 6,8cm is not such a huge difference I hear you say, so get the cavity back to where it was and you'll have a resonant frequency of 42,8Hz with 26,4cm wall thickness (less than a foot).
Not bad for my wall separating the Control Room and the Live Room, not bad at all! Unfortunately, resonant frequency at 42,8Hz for my perimeter wall is TOO high (Harley Davidnson parking, remember? :roll: ). I have to get much lower than that AND much higher for mass... :(
Introducing... the concrete wall! Now it gets really interesting! Compare the f(32, 32) and the f(16,150) data sets. The single layer of drywall on one side, concrete blocks on the other has a HIGHER resonant frequency than our two layers of drywall on each side champion we discussed! Even if we replaced the 3,2cm thick double layers of drywall with 15cm concrete blocks, we decreased the thickness of the other side! Conclusion: BOTH panels' thickness should be equally considered on our walls. Same conclusion applies if we compare f(32, 150) with f(16, 300) data sets. Stick with two layers of drywall on one side of your wall boys and girls... :wink:
Another interesting point arises when we compare f(32, 150) and f(32, 300) data sets. Even if we doubled our concrete block wall, the difference in resonant frequency starts at only 5,4Hz for 1cm of cavity depth and reaches... 1,2Hz for 20cm cavity depth (lowest frequency at 32,7Hz and 31,5Hz respectively)! Have we just sacrificed 15cm of space for 5,4Hz or 1,2Hz difference in resonant frequency? :shock: I don't think so! :evil: Hold your horses, I hear you say. You forgot about Mass Law. Well, a 15cm thick concrete block wall is pretty massive, don't you think? And according to Mass Law, I'm gonna get a 6db TL increase. Does it worth it, considering the additional cost? IMHO, no way! On my last design, I used the two drywall layers - 20cm cavity - 30cm side of concrete blocks assembly. Watch me how fast I'm gonna modify this to 15cm concrete blocks wall side... Unless, someone has an objection that would like to share... :wink: Seriously, 32,7Hz (the resonant frequency from the f(32, 150) data set with 20cm of cavity depth) is pretty low but... is it low enough for my situation? I honestly don't know... What do you think?
Only with the last three data sets, concrete blocks on both sides (I'll finish this soon, I promise! :oops: ) we have a resonant frequency lower than 20Hz. Since we can get that frequency range from the f(150,150) data with less wall thickness than the other two data sets, I'm not going to further elaborate on those. If we compare the f(32, 150) with cavity depth 20cm (32,7Hz, lowest frequency) and the f(150, 150) with cavity depth 16cm (19,7Hz, first frequency below 20Hz), we get a 6,8cm wall thickness difference, which is of little importance in comparison to the 13Hz difference in resonance. Cost of construction on the other hand is of huge importance to me... :(
Conclusions from this study? I'm all ears (or eyes :lol: ) for comments but from my point of view, I cannot determine the wall assembly I'm going to use unless I determine the sound level and frequency range of sources resiting outside the studio. Theoretically speaking, if I can afford the 15cm concrete blocks - 15cm cavity depth - 15cm concrete blocks wall assembly, I'll use that, if I can't, I'll use the 3,2cm two drywall layers - 20cm cavity depth - 15cm concrete blocks assembly. I think I can afford that... :?
Now, excuse me but I have to break a concrete wall down in half... :mrgreen:
Respect,
John
Hang on, John! One quick question: have you actually MEASURED the spectrum of the Harley's (and other offending vehicles!)? If that is your major concern, then why not do some real measurements on real offenders, to find out where your real problem will be.
Just a suggestion.
Or did you already do that?
- Stuart -
PS. Thanks for figuring all the numbers! Very useful info there!
have you actually MEASURED the spectrum of the Harley's (and other offending vehicles!)?
In simple words, no... :) But it's right at the top of on my check list, as soon as the two garage floors are build.I cannot determine the wall assembly I'm going to use unless I determine the sound level and frequency range of sources resiting outside the studio
I hope I didn't make a fool of myself for using the wrong equation or substituing the wrong data... thanks man! :thu:Thanks for figuring all the numbers! Very useful info there!
Hello friends, I hope you are doing fine with your lives!
Searching through this forum for soffit designs that I could study, I realised that there weren't any that offer the kind of detail I need. John's and Barefoot's designs are excellent to get you started, lots of work-in-progress/finished photos to give you the look&feel of the project but that's about it... Since I never did any major carpentry (building my dog's house doesn't really count, does it? :roll: ), I felt the need for 3D implementations. I searched for sketchup designs but the only decent one I found was John's Small Studio design. JohnS was generous enough to give us a great soffit design to work with and that's exactly what I did.
I designed the soffits based on my Control Room's dimensions, front wall is a bit narrow but I managed to sqeeze them all in there. For speaker dimensions, I used the Genelecs 1032A model, although I read somewhere that they are too big for a small Control Room like mine. Any thoughts on that? Any other models that I should consider? Monitor soffit should be big enough to hold a 32" flat monitor/tv.
You can check each individual component of the soffit design (frames, insulation, plywood etc.) by using the appropriate tabs (it was about time to start using components and layers :roll: ). I didn't use acoustic hangers like JohnS did, I used corner superchunck bass traps instead.
If you check my design out (I wish JohnS or Barefoot would comment on this one), and you think that I missed or misplaced something, anything, please, tell me about it, so that I could fix it.
Until next time,
John
Hey, John. Good idea to post soffit designs! I wish there were more of those. Or maybe even a book on the subject!
A couple of comments from my limited understanding of soffits:
1) John recently told me that it is a good idea to extend your soffit panels down lower to the floor, instead of cutting them off at the top of the bass trap. Just leave a large gap at the base for the bass traps. So the top section of the bass trap will be "hidden" behind the bottom section of the panel, and only the bottom section of the bass trap (a few inches) is directly exposed to the room. The idea (IIRC) is to get the soffit panels (read "infinite baffle") as big as possible in all directions around your speaker, for best acoustic effect. They need to be large, flat, massive, uninterrupted surfaces, with your speaker in the middle.
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EDITED TO ADD: Since originally writing this a few years back, I have since learned that the speakers should NOT be in the middle of the soffits, but rather offset to one side or the other, in order to avoid creating peaks and nulls in the frequency response. It seems that a position about 2/5 of the width is good. They should also not be centered vertically, for the same reason. That said, you do still need a lot of surface on all sides of the speaker. - Stuart -
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2) I see that you have plywood between your studs, not on the front of them, and all you have on the front is your finish wood. I'm not convinced that's the best way to do it. I know the idea is to have as much mass as possible in your panels, so I kinda intuitively feel (but can't think of a good reason!) that one large thick sheet of plywood / OSB / MDF over the studs, plus a thick layer of the finish wood, would be better than several smaller pieces of plywood between the studs and thin finish. Maybe one of the soffit experts can comment on that?
3) On John's design, he puts the cooling ports way up high on the soffit panels. Yours are right above the speakers. My guess is that John does that: 1) once again, to have as large an interrupted flat surface as possible on the soffit panels, and 2) perhaps something to do with not having it act as a bass port? Dunno about the second one, but I'm pretty sure that the first one is right. I do know that you need as much solid flat massive real estate around your speakers as possible. Maybe it might be an idea to move your cooling port to the top of the soffit? (Also, your cooling ports are covered with insulation at present! You probably need to cut a hole in that, for better air circulation!)
4) The flat screen monitor.... hole cut in the center soffit panel to mount it? .... hmmmmm.... not sure about that. Can't think why, but it doesn't convince me that cutting a big hole in there is a good idea... I'm thinking that just mounting it on the surface might be a better idea. Also, if you DO mount it "in" the soffit, then I reckon you'll need cooling ports for that too! Don't know about yours, but my 32 inch gets pretty hot. It needs cooling airflow. I would not want to seal it in an un-vented box like that.
5) "Plywood": I think John recommends OSB or MDF instead of plywood. I might be wrong on that, but I seem to recall reading a comment from him somewhere. I think the reason was mass vs. cost, or something along those lines? Not sure...
Anyway, that's just my $0.02, from my murky understanding of soffits! Take it with a large pinch of salt!
Personally, I'm going with concrete soffit panels for my room. Did you see the "in progress" design I'm working on for that, and the associated discussion with Andre? It might be useful for you.
- Stuart -
uhm..... :twisted:Don't know about yours, but my 32 inch gets pretty hot.
As long as it's finished and works as 1 layer, it's cool. (just like sealing of GB wall sections etc) Which brings me to:2) I see that you have plywood between your studs, not on the front of them, and all you have on the front is your finish wood. I'm not convinced that's the best way to do it. I know the idea is to have as much mass as possible in your panels, so I kinda intuitively feel (but can't think of a good reason!) that one large thick sheet of plywood / OSB / MDF over the studs, plus a thick layer of the finish wood, would be better than several smaller pieces of plywood between the studs and thin finish. Maybe one of the soffit experts can comment on that?
Same thing, make it part of the whole layer. Flush the screen with the wall and it will do the job, IMHO. (but I'm no expert on these matters)4) The flat screen monitor.... hole cut in the center soffit panel to mount it? .... hmmmmm.... not sure about that. Can't think why, but it doesn't convince me that cutting a big hole in there is a good idea... I'm thinking that just mounting it on the surface might be a better idea.
mass... MDF of GB have more mass per volume than Plywood or OSB does.5) "Plywood": I think John recommends OSB or MDF instead of plywood. I might be wrong on that, but I seem to recall reading a comment from him somewhere. I think the reason was mass vs. cost, or something along those lines? Not sure...
same here...Anyway, that's just my $0.02, from my murky understanding of soffits! Take it with a large pinch of salt!
A good idea (to me), to finish of the whole panel, would be to put stucco on it. Cement or gypsum based. Concrete panels are hard to make I think, but it would be cool if you got it done!Personally, I'm going with concrete soffit panels for my room. Did you see the "in progress" design I'm working on for that, and the associated discussion with Andre? It might be useful for you.
Hey Stuart and Ro, thanks for checking my design out and for your well placed comments, some of them are refering to "grey areas" for me also, the main reason I made this design in the first place! I would hate to go to my carpenter with just blueprints and without knowing exactly what I was talking about!
The soffit panels extend down to the floor (30cm from the floor actually) just like John's design. The difference is that this extension goes a bit inside to provide space for the insulation in front of the panel. John does this to absorb reflections from the console. It's all in there, go to the "plywood" tab and check the bottom part of the soffits, you'll see it. :thu:John recently told me that it is a good idea to extend your soffit panels down lower to the floor, instead of cutting them off at the top of the bass trap.
one large thick sheet of plywood / OSB / MDF over the studs, plus a thick layer of the finish wood, would be better than several smaller pieces of plywood between the studs and thin finish.
Stuart, you got me thinking there... While I was designing the frames, I was considering the panel placement, on the frames or between them? I decided to place them between frames thinkng like Ro did, it's a solid layer after all, but now I'm not so sure... :?As long as it's finished and works as 1 layer, it's cool. (just like sealing of GB wall sections etc)
John's design (attached below), as great in detail as it is, lacks in terms of scale. If it was in correct scale, floor-to-ceiling distance would be approximately 1.8m (6f). If it was the distance between the speaker box and the cooling port he didn't scale then you're right, the cooling port should be right at the top of the frame, if it was the distance between the cooling port and the ceiling he didn't scale, the cooling port should be about 30cm (1f) from the speaker box. Which one is correct though? Oh, and in case you don't feel unbalnced enough :roll: , check what JohnS did with Meow Mix Studio's soffits (photo attached below)! 3 cooling ports for each speaker, a few inches away from the speakers! Talking about "grey areas"... :?On John's design, he puts the cooling ports way up high on the soffit panels.
You spotted that little detail? :shock: Wow! :lol: Well, according to John's design that cavity is filled loosely with insulation. Therefore, without the cloth in front of the cooling ports, you would actually see the insulation inside. I didn't cut a hole in there in order to simulate that effect. Great eyes though! :thu:Also, your cooling ports are covered with insulation at present! You probably need to cut a hole in that, for better air circulation!
The flat screen monitor.... hole cut in the center soffit panel to mount it? .... hmmmmm.... not sure about that. Can't think why, but it doesn't convince me that cutting a big hole in there is a good idea...
I thought about having the monitor hanged on the surface of the panel (that's what JohnS did in Small Studio sketchup design) but due to the small distance between the speakers and the monitor, I'm conserned about the reflections from the monitor's edges... Flushing it would make the monitor an extension of the panel. And it would look great too! :wink: The real question here is, do we place the monitor in a box attached to the front frame similar to the speakers' boxes or just hang the monitor from the back frame, up to the hole in front (I didn't include that detail in my design)? Stuart, if you're conserned about having a hole in your panels, let me remind you that we have a huge hole along the bottom of the front frame. So, it's not a matter of making the front frame air-tight, it's more about making the panel as wide as we can. That's a huge "grey area" that we need to clear up... :?make it part of the whole layer. Flush the screen with the wall and it will do the job
Don't know about yours, but my 32 inch gets pretty hot.
:shock: HAHAHA!!! :lol: I love this forum! :yahoo:uhm..... :twisted:
I think John recommends OSB or MDF instead of plywood.
Well, it says "plywood" on John's design so I named it like that (I actually used sketchup's OSB material for that... :lol: ). It's not that we have too many options for panel materials and it doesn't really affect the overall design principles, so, when the time comes I'll talk to my carpenter about cost vs mass ratios... :thu: A quick note though... I think JohnS uses plywood (solid enough but less dense than MDF or OSB) because he doesn't want the soffit panels to become a 3rd leaf with Control Room's front wall. Any thoughts on that? :? Keep a cool head (and your 32 inch Stuart :lol: ), Johnmass... MDF of GB have more mass per volume than Plywood or OSB does.
Yeah, that's what I think too, but I'm just stubborn enough to want to try anyway! :) I figure that, in the worst case, I can either do what you suggest (stucco), or I can paint it black and cover it with acoustic cloth, to hide the ugliness.Concrete panels are hard to make I think, ...
Stay tuned! When I get around to that part in a few months, I'll certainly post photos for you guys to laugh at, so you can say "See? I told you it was not going to be easy!". :) Fortunately, concrete is fairly cheap here, so I can mess up a few times while I try to get it right, without breaking the bank.... but it would be cool if you got it done!
Hello, long time, no see! I've been really busy outside the studio project but now I'm back to give you an update of my final design. I decided to draw it again, but this time the whole process would be with as much detail as possible, much like building the real thing!
I think I got it down as best as I could, so check if you please the compressed sketchhup file I attached cause this is more or less what I'm going to buld (except for the acoustic treatment, that would be the next step)! If you notice any problems that would translate badly when construction begins (hopefully in a couple of months), I would really appreciate it if you point them out.
Always thankfull for your time,
John
You are floating your floor???!!!!?!?!?!?! :shock: - Stuart -If you notice any problems ... I would really appreciate it if you point them out.
Yes, Stuart, I'm sure I've mentioned it on my last design update that I would "float" the CR's and LR's floor because I'm conserned of the structure bourne noise and vibrations from vehicles parking right beside the studio's perimeter wall and from the noisy neighbours (lift, boiler, water pumps). It's imposiible (for many reasons) to pour a separate slab underneath the studio's space in order to separate the perimeter concrete wall from the building's existing floor slab. I have to live with that. Inner wall frames though, could be placed on floor elevated frames sitting on neoprane pads with insulation in between to eliminate resonance and with a layer of drywall, a layer of plywood and a layer of wood finish on top. Check John's designs attached below to compare with what I did. Stuart, why are you so suprised by the idea of floating the CR's and LR's floor? Can you elaborate further on that? Maybe I'm missing something and you could save me the trouble and a few hundred bucks with an alternative idea? Please do so! :thu: JohnYou are floating your floor???!!!!?!?!?!?! :shock:
Well, my only question here then, is: have you done all the necessary calculations!
If you have, then you will be able to answer these questions without even thinking about it:
What resonant frequency are you shooting for? How much mass do you need in the floor to get that frequency? How are you going to achieve that mass, if you don't want to use concrete? What air gap do you need under the floor to get that frequency? What pucks did you choose? What layout did you come up with for the pucks? How much deflection will your specific mass give you on your specific pucks in that specific layout that gives you the specific resonant frequency that you are shooting for?
From your SketchUp file, I don't see anywhere near the amount of mass that you will need to get to even a half decent resonant frequency.
Floating a floor is serious business. If I recall correctly, John mentioned that in his entire studio construction career, he has only ever needed to do it once or twice, and that was in multi-megabbuck professional studio builds.
Did you read this thread, carefully?
FLOATING FLOORS: viewtopic.php?f=2&t=8173
Floating a floor is not something you do lightly. If you do not do it exactly right, you end up making things much worse than if you you would have not floated it at all.
I'm not saying that you should not do it: I am saying that you should be very, very aware of what it involves to get it right, in terms of design, calculation, mass, construction, etc., and the consequences of getting it wrong.
Probably because I almost made the same mistake you are about to make, until I found this forum and realized what a truly bad idea it is to float a floor if you don't know what you are doing (like me) and don't have many thousands of dollars to spend doing it right (I don't)! :) - Stuart -Stuart, why are you so suprised by the idea of floating the CR's and LR's floor?
Stuart, I hear what you're saying and I'm really gratefull for your concern and advice. Believe me when I say that all those questions you're throwing at me were always on my mind when I was considering the floor design.
The point is, it's not something I'm considering for certain, I've just designed it to get the feeling of the construction envolved and to have something to show to my brother (the contructor). I've read the threads about NOT floating the floor but at the same time I've seen many construction threads that utilise floating floors based on John's designs without problems or complaints. So I'm a bit torn inside about this issue. And I don't think JohnS posted those designs just to show his work for one studio construction. It depends on the situation really.
I decided to float the floor in my design because it's something optional that I can always remove after I discuss this with you and my contructor. He will be responsible for those calculations you are refering based on mass and neoprane pads type and placement and if he assures me that resonance will be around 20Hz and structure bourne noise will be contained, I'll go for it.
You see, the way I think about this is that floor and ceiling should be treated as a typical double frame wall. The tricky part with the floor is to maintain an air gap between the subfloor and the inner floor without allowing structure bourne noise to pass through. Mass should be considered like building an inner wall frame, hence the drywall-plywood-wood finish layers with insulation underneath.
If I add an additional drywall layer and if we apply the same calculations as a normal wall that I did a couple of posts back, we will determine that its resonance frequency will be pretty low. Actually, lower than the 32,7Hz that we detrmined earlier (we add plywood and wood finish mass to the total mass, remember?).
Well, that's not entirely true because we forgot about one little thing: our walls are connected together by steel frames on neoprane pads. The same equation doesn't apply here. If anyone knows a formula to determine the resonance frequency of that construction, be my guest, bring it on! If not, I'll get my contructor to calculate that.
Then, it's the cost of the bloody thing to consider! If it's too high, consider it off the design. If it's on budget, consider it done.
Thanks again for your comments, very stimulating to discuss these with someone other than yourself... :idea:
And acoustic treatment is on the way... :wink:
John
Hi again, John. Just to add some fuel to the fire: :)
Firstly, I was wrong about John saying that he has floated floors a couple of times. In actual fact he has only ever found the need to do it ONCE. His comment: "I've only floated one studio floor in the past set of studios I've designed. The first studio in Dubai has a floated floor because it is on the 6th floor of an office block so it was necessary to isolate from the offices below. All the other projects are on concrete slabs in house basements or industrial sites and have cosmetic timber flooring only in the exposed floor areas." So, if John has only ever found it necessary to do that once in recent years, then I'm wondering what it is about your case that makes it necessary? I don't recall the details of your existing floor: maybe you could refresh my memory?And I don't think John S posted those designs just to show his work for one studio construction. It depends on the situation really.
Has this constructor built studios before? Successfully? Has he done those calculations before? The calculations are not for the light hearted! Take a look here, for example: http://www.earsc.com/HOME/engineering/T ... asp?SID=61 You need to do those types of calculation for each individual puck in your floor, and for all possible load conditions. If your contractor has SUCCESSFULLY floated several studio floors before, and you get to go see them and talk to their owners, who give them unanimous happy reviews, then all is well. But if you are his guinea pig, then that would be a major red flag for me!... and my contructor. He will be responsible for those calculations
20 Hz is way too high! If your floor resonates at 20 Hz, it will BOOST sound transmission in the range 20 to 30 Hz (roughly), and you wont get any reasonable level of ISOLATION until you are well up in the 50 - 100 Hz region. Kick drums, bass, toms, other things all put out considerable energy in this area. So do cars, trucks, and motorbikes.... You need to shoot for a floor resonance of way below 20 Hz! So: far from improving things, if you can only get your resonance down to 20 Hz, then you will be making things worse, not better. You say that you are concerned about traffic noise getting in but think of this: a four-cylinder four-stroke engine turning over at 600 RPM has 20 cylinders firing per second, which is the exact frequency at which your floor would transmit sound BEST... A floor with a resonant frequency of 20 Hz would do a really good imitation of a drum head, tuned to the idling frequency of some cars, trucks, bikes.... Food for thought... There is the other issue that you may not have considered: Live load / dead load. Since your design at present is for a low-mass floated floor, you need to repeat the calculations for all possible load scenarios, to make sure that the floor will still work. For example, you will probably do your calculations considering the load of the walls, ceiling, basic equipment, and you. Your floor might work fine like that. But add another four or five people, a bunch of instruments and amps, and a couple of cases of beer (don't forget that!), and your pucks might end up "bottomed out", so your floor is no longer floating at all. On the other hand, you might decide to take out the sofa and a rack of equipment for some reason, and find that your pucks are now fully uncompressed by the remaining mass, so once again, your floor is not floated. In both cases, you have a direct flanking path to the underlying floor, and a tuned cavity in between. Not a happy situation! With a light-weight floating floor, such as you propose, that extra variable load is a large fraction of the total normal mass load on the pucks, and it will be changing greatly all the time. You need to be very careful to check that your pucks are always loaded in the manner specified by the manufacturer: You can't just spread around a few pucks and hope for the best! Each and every puck needs to be compressed to the correct range within its design limits, not more and not less. so that means you need to know the exact loading that will occur at each of the points where you plan to have pucks. If even one single puck bottoms out or tops out, then your floor is no longer floating, and is now flanking. Since your floor will be flexible (it is only a timber frame), loads will not be spread evenly: Six people sitting on the sofa at the back might bottom out all the pucks back there, but not affect the ones at the front of the room at all. You also need to choose the right puck for each location: Do you use heavier duty pucks under the walls, or do you just use more of the same pucks, spaced closer together? Only calculations can tell you that. Do you need more pucks at certain places where the load is higher, such as under the console / rack / speakers? And you leave out certain pucks where the load is lower? Once again, you have a whole truck-load of calculations ahead of you to figure that out. And each time you change the puck configuration, or the loading condition, you need to re-do all of them. "Gee, I think I'll need an extra layer of drywall on the ceiling". Re-calculate the entire floating floor. "Hmmm. I think I'll fill my speaker stands with sand". Re-calculate. "What if I move the rack over to the other side?" Re-calculate. "How about if I install a bar fridge and coffee nook?". Re-calculate. "How about if I use 10mm laminate floor instead of 6mm, and put some throw rugs on top?" Re-calculate. In short, any change you make that adds or removes more than a few dozen kilograms of mass, means that you need to re-calculate all of your equations, for each individual load point and each individual puck of your floating floor. You might think I am exaggerating, but consider this: If you have, for example, a total floated room mass of two thousand kilograms resting on those pucks, and you add a pair of nice solid 50 kg concrete-filled speaker stands, you just changed your floated mass by 5%. If your pucks could only take another 4%, then they are now fully compressed, bottomed out, and you just killed your floor: it no longer floats. (And there is no way that you would know about it, other than that your isolation just got a hell of a lot worse.) In order to avoid that kind of issue, you need a truly massive floating floor (several tons of concrete), where these types of changes in mass are only a very small percentage of the total floated mass. When I first came here, I was all fired up about floating my floor, just like you are, until I started to research the physics, mathematics, economics, and reality of doing so. Then I got scared, woke up from the nightmare, and decided that this is NOT something I want to do. I would blow more than my entire budget for the complete room just on floating the floor. Once again, I'm not trying to tell you that you should not do it, if you really need to. I'm just repeating what I learned from listening to the experts here, on other forums, and in books: The probability that you actually really do need to float your floor is pretty low, and if it does turn out to be necessary, then you probably should not try to do it yourself: In that case, you really should hire someone like John or Rod, who know what they are doing, know how to do the math, and have done it all before, successfully. OK, I think I'll stop ranting now! :) - Stuart -... and if he assures me that resonance will be around 20Hz ...
I just thought of another idea:
It might be a long shot, but can you CUT the existing slab, to separate it from the rest of the building?
For example, if you could cut through that concrete slab floor, all around the edge of your space, then you would effectively decouple your floor from the rest of the floor, and most important, from those noisy things around you. Of course, you will need to get a structural engineer to look at this and tell you if it is possible, but it might be worthwhile! If you CAN do that, then it would be a lot easier than trying to float your floor.
I imagine that it probably will not be possible to do that, but it would be a good idea to hire a structural engineer anyway, to examine the issue, and tell you for sure, and also to let you know if you have other potential issues that you need to consider.
- Stuart -
"If you CAN do that, then it would be a lot easier than trying to float your floor."
You have obviously never demo'ed a concrete steel reinforced structure.
It can be done, but you have to re-enforce the perimeters. Building heavy walls on there would destroy the concrete. IIRC there's a note with a solution in Rod's book about that (have to check, but I'm pretty sure)
Geez, Stuart, when you get fired up, nothin' stops ya! :lol:Hi again, John. Just to add some fuel to the fire: :)
And I don't think John S posted those designs just to show his work for one studio construction. It depends on the situation really.
Sure, I'll refresh your memory alright! :horse: :lol: Seriously, my situation is unique in a way because of the location of the studio. I haven't seen any threads in this forum or any other forums of building a studio 1m (3f) away from parking spaces with machiney all around! It seems I'm the only one crazy enough to try it. :mrgreen:So, if John has only ever found it necessary to do that once in recent years, then I'm wondering what it is about your case that makes it necessary? I don't recall the details of your existing floor: maybe you could refresh my memory?
and my contructor. He will be responsible for those calculations
Well, not really, no, but the contructor (my brother) is a civil engineer with experience on anti-earthquake solutions, and when someone designs and builds structures to contain such a low frequency bourne noise as an earthquake, you pay attentiion to him! :wink: The principles envolved should be similar, only on a different scale. I'll show him my books about this subject and I'll get his professional opinion.Has this constructor built studios before?
and if he assures me that resonance will be around 20Hz ...
Come on Stuart, I know and you know that we can't get such a low frequency without an isolated or floated concrete slab... And I guess it's not an easy task to perform on a 460m2 foundation slab supporting two underground floors plus five appartment floors above ground without having reinforcement issues. We'll discuss my options, and I'm sure the ratio quality/price will come up... :(You need to shoot for a floor resonance of way below 20 Hz!
Hi Brien, it's been a while since your last comments on my thread, welcome back man! Really appreshiate your feedback! I'm sure that's what my brother will say, that's why we'll be considering my options before he pours the foundation slab.You have obviously never demo'ed a concrete steel reinforced structure.
Ro, always appreciate your comments, another good point that my brother will seriously consider, as I mentioned above. Since I decided to build my studio for personal usage and not for hiring, I could live with all my walls standing on the foundation slab and have all these structure bourne noise problems, I would have background noise on some of my recordings BUT I would save a substantial amount of money to put it somewhere more useful (acoustic treatment for example). That's an option. Another (expensive and difficult to apply) option is the isolated/floated concrete slab. And a third option is the neoprane pads-frame-insulation-double drywall-plywood-wood finish layout, not so expensive and hard to build but risky if you don't do it right. Thank you all again for your time :thu: , JohnIt can be done, but you have to re-enforce the perimeters.