Studio construction - is this any good?

I know there has been numerous posts about this, and I've tried to read thoroughly thru most of them to get wiser, but I would so much like to have your input on these drawings and choices that my contractor made. I'm in Europe, so I will use metrics. Liveroom from the bottom and up: As it's an old house I'm having rebuild, I'm not sure how the foundation is. Most likely concrete. We were talking about putting 100mm armed concrete on top. The concrete slab will be split between live room and control room. Then 350mm Polystyrene. The floor itself will be constructed according to my "drawing2", which I have lifted off from SAE. Same goes for the walls and ceiling. What I'm afraid of is that the external noise will too much. I have neighbors in 30 meters range NorthEast from the live rooms outer corner. I don't care too much about the acoustics inside, as I have a nearly identical room right now, that I have damped lightly and put up a few diffusors, and it sounds amazing for drums, which is what I'm gonna record 90% of the time. I am aware, though, of the fact that an extra loud and noisy room on the inside will affect the outside noise. Any ideas and thoughts? Let me also know if I'm a little short on info here... :D Thanks!

The site you refer to sae, John L Sayers is the author of. That said, Most of what is there in this picture is of value, excepting the floor, I wouldn't recommend this at this point in time. I cannot speak for John, but he might even suggest an alternative, being that the information on that site was developed from information a decade or so ago. Having a room sound good is fair enough and is relatively easy to achieve...but the isolation ( the ability to contain the sound within the boundaries of said room) is more difficult than can be expressed in a few simple paragraphs...so we often ask for more information...that request will now be submitted :)

Hi Hansen, and welcome! I agree with Brien: I wouldn't do the floor like that either. If you have a good concrete floor, then just leave it like that! Acoustically, concrete is a good surface for a floor. Or if you don't like the look of concrete, then lay laminate flooring on top of it.

Then 350mm Polystyrene. ... Same goes for the walls and ceiling.

Polystyrene is closed-cell foam, and therefore is practically useless acoustically. A drum kit is the most difficult instrument to isolate, due to the high levels (115 dB, easily), and low frequencies. To isolate, you need mass, all around the room: walls, floor, ceiling, windows, doors. The best way to achieve high levels of isolation at a reasonable cost, is with a two-leaf system, just as you see in John's diagram that you posted: In that case, the outer leaf is brick, and the inner leaf is two layers of 16mm drywall. As you can see, there is no connection between the inner leaf and outer leaf. The ceiling is done the same way: outer leaf and inner leaf, with no connections. Now, the amount of mass that you will need, and the amount of separation that you will need between the leaves, will be determined by your numbers: How much isolation do you need? (in decibels). What is the lowest frequency that you need to isolate?

Let me also know if I'm a little short on info here...

Yep! :) As Brien said: you'll need to provide a lot more info, such as your numbers (see above), the amount of space you have available (length, width AND height), the existing construction (in detail), your goals, your budget, etc. - Stuart -

Thanks for your input! Highly appreciated. More info... The thing is, that I'm not responsible for the design nor construction, so I haven't given it THAT much thought, and obviously, I see now that I should have done earlier. I am just "keeping an eye" on my contractor and sent him the SAE links for information. My idea was to build my live room "room in room" (exactly like I found on SAE - from John :oops: ), isolated on neoprene pads placed on the concrete foundation. I don't know why the contractor wants the polystyrene. I think moist/heat isolation because of heating system in the floor?! My best guess, as I haven't had the chance to talk to him about this yet. You see all the numbers on "drawing1". The live room being 8x7,3 meters, and 2.5 from floor to ceiling. And yes, I want to contain the sound in there. I am hoping that 25 meters from the live room, the alleged 110dB will not surpass 55dB, which is the maximum in my country. And since it's drum, I'm thinking 60Hz is the lowest (and I believe it's not more than 70-80dB here), and 10-12kHz is the highest (again the loudest part of the sound is probably the snare "crack" around 500Hz - 3kHz). Are there any resources about that anywhere? Someone measuring a drumkit being played in a studio? That's where I'd like someone to give me some good ideas to the construction of a room that will work for me :D

The thing is, that I'm not responsible for the design nor construction, ... I am just "keeping an eye" on my contractor and sent him the SAE links for information.

:shock: Please tell me he has plenty of experience designing and building professional studios? If not, I really hate to say it, but this does not bode well for a successful outcome. Not trying to scare you: Just laying it the way I see it. Building any type of acoustically isolated structure is nothing at all like building an ordinary house or office. There are many similarities, for sure, but there are also a few major, and I do mean MAJOR, key differences. If this contractor of yours has never designed nor built any studio before, the chances of him getting it all right from simply looking at a few diagrams from a paper that John wrote many years back, are pretty close to zero. Even if John himself designed this place for you, but you then allowed a contractor with zero experience in acoustics to build it, then chances would still be pretty slim. But to let him both design and also built it, all by himself, well.... I'd expect that work about as well as I'd expect a butcher to be able to do brain surgery on humans, successfully...

My idea was to build my live room "room in room"

Room-in-a-room is great! ... if you know how to do it right! It isn't just a matter of following a basic diagram found on the internet.

I don't know why the contractor wants the polystyrene.

The simple fact that he even specified it, indicates that he knows precious little about acoustic isolation!

I think moist/heat isolation because of heating system in the floor?!

Hang on a sec there! There's an underfloor heating system, and he wants to put polystyrene on top of it? :shock: There's an underfloor heating system, and he wants to float an acoustic isolation floor on top of it? :shock: :shock: Ummmmmm.....

And yes, I want to contain the sound in there. I am hoping that 25 meters from the live room, the alleged 110dB will not surpass 55dB,

OK, so the first part of your design goals is; TL of at least 55 dB.

And since it's drum, I'm thinking 60Hz is the lowest (and I believe it's not more than 70-80dB here), and 10-12kHz is the highest (again the loudest part of the sound is probably the snare "crack" around 500Hz - 3kHz).

There's a huge difference between "loudest part" and "part most difficult to isolate"! Isolating 3 kHz to 55 dB TL is a piece of cake. Isolating 60 Hz to 55 dB TL is practically impossible (and unnecessary, too). Now, since you are talking about drums, I'm guessing that bass guitar also plays a part here? And since we are talking about acoustic drums, I'm guessing that impact noise flanking through the building structure is also a possible issue here? If so, specifying 60 Hz as your lowest frequency of interest is probably optimistic.

Are there any resources about that anywhere? Someone measuring a drumkit being played in a studio?

I've done that myself, many times! None of them scientifically valid, of course, as I did that in various places, with various drums, mics, drummers, etc., and never in an independent acoustic lab. But for what it's worth, levels of 115 dB are common, and 118 isn't out of the question. Adding a bass guitar can get you pushing 120. Much of that is in the low end of the spectrum, and as I mentioned before, isolating sounds above 2 KHz is nowhere near as hard as isolating sounds below 200 Hz.

That's where I'd like someone to give me some good ideas to the construction of a room that will work for me

For possible construction methods that will get you 55 dB of isolation, I'd suggest starting with IR-761 for walls, IR-766 for floors, and IR-802 for a better understanding of impact noise. I'd also suggest "Master Handbook of Acoustics" by F. Alton Everest. (That's sort of considered to be the "bible" of acoustics.) And if you really want to get a good handle on the whole "fully decoupled MSM two-leaf room-in-a-room" thing, a really good place to start is with the Wyle report (WR 73-5). Finally, I'd add "Home Recording Studio: Build it like the Pros", by Rod Gervais. That will give you much more detail about the practical side of construction. Studying those will give you a really good understanding of how to design your room completely, including things that you haven't mentioned yet, but that are extremely important, such as the HVAC system, the electrical system, doors, windows, and the single most important point of all: airtight sealing. - Stuart -

Thanks for all the information and ideas of what to read. I wont bore you with more details from my contractor, as his drawings are not final. But I will give him the PDF's with IR-761+766 and IR-802. Thanks!

"I don't know why the contractor wants the polystyrene. " He wants it because he has no idea what he is doing. If it where to be used for anything, it would be part of a thermal shield on the exterior of the structure. Outside of that, and I believe Stuart covered it already, it has no value in a floor...period. Typically you would use lightweight cement. I know, I know...there are floors that are made of wood with this type of configuration....but you want mass....sand...concrete...dirt...rocks...MASS!!!

The polystyrene may well be used in a floor between the existing floor and the new poured concrete, acting as Brien said, as a thermal shield, especially if the new slab will incorporate heating. 350mm however is rather extreme (35mm?) and this layer will go beneath the slab and not on top of it.

Brihar is right. I believe this guy actually knows a little about what he's doing. Just got the measurements back from an acoustic measurement company, and things are looking good. But thanks for all your thoughts on this.

Just got the measurements back from an acoustic measurement company,

What measurements? What exactly did they measure, and in what way are things "looking good"? Just curious. - Stuart -

Hansen wrote:

Brihar is right. I believe this guy actually knows a little about what he's doing. Just got the measurements back from an acoustic measurement company, and things are looking good. But thanks for all your thoughts on this.

It isn't a measurement of anything but a thermal environment. If in fact this is a heated floor then the process has nothing to do with acoustics of this floor but only to do with "typical" installation. which does not produce mass...only an attempt to make the heat work as it might be expected to based on procedure. And you did say this was your design Hansen, so your design abilities are now under question. Then you said "Then 350mm Polystyrene." Ok 13.75 inches(350mm)of polystyrene is way too much. The better way out, based on the little I know of this project would be to install the heating coils into the lightweight concrete. The polystyrene is going to make a hard connection so it has little use as best as I can tell in this configuration and is taking away all of your available head room. You are attempting to do a mass/spring/mass but you are making hard connections at every step of the way. Get rid of the polystyrene and install mass. At least, you can get a 2 inch Owens Corning 703 or comparable product, possibly rockwool, and install that in the area instead of the polystyrene. I agree your floor guy/heater guy knows what he is doing, but only in respect to this heated floor, out side of that....he is incorrect.