thinking of a control room

Hi Folks: My first question here, I hope everything is cool with my profile to do it. Our "studio/live entertainment" venue is sorely lacking in the CR dept. I am thinking of building a new one to get started. To start, the "big room" where this is going has evolved by other buildings being put in, that made the general space, the gaps between the buildings were just filled in, a roof put over it (uninsulated...yikes), and a concrete floor poured. Then a few walls put in to divide out a shop and other small spaces (not really pertinent to the question, but please allow my digressions). The room is quite pleasing to the ear with the open joists on the ceiling, some drapes, the stage, etc., but on to the question......There is a space that is available to build a new control room and I am thinking about it, starting with the basics. Would it be recommended to put down a floor system like DRIcore http://www.homedepot.ca/webapp/wcs/stores/servlet/CatalogSearchResultView?D=931386&Ntt=931386&catalogId=10051&langId=-15&storeId=10051&Dx=mode+matchallpartial&Ntx=mode+matchall&N=0&Ntk=P_PartNumber for the floor of the CR to start? OR, is there a less expensive solution? OR, just keep the concrete floor and put a laminate floor right on it (though I cannot guarantee it will stay dry)? Thank you Jim

welcome! why would the floor ever be wet? you want to fix that first... as far as adding a floating floor (dri-core or otherwise) you should consider your isolation needs - the concrete floor as a sound source may be minimal or well within your requirements. it would only generally become the main flanking source after your walls and ceiling go over 50db of isolation. but you can test that using metal and rubber hammers to determine just how much transfer through the floor you are getting, secondly using a contact mic and some sine wave tests to see what frequencies and levels are really there. then you can work out a strategy to defeat them. maybe damped membrane floors all around will solve impact or other structure borne noise.

I thought it would help in both isolating the CR and keep the comfort level up by not having your feet on the concrete. I figured that I would build the walls on top of the dricore. I am not expecting to be getting great isolation, as it is not my dime this will be done on. The walls will likely be 2x3 wood studs staggered on 2x6 top and bottom plates. Have not gotten far into thinking about this, just researching. I am a complete newb at 50 yrs. old. Umm, sine wave tests are beyond my understanding. I just want a decent room where I can sit at the 2 boards, be comfy, and get decent results. I am slowly cramming all this new info into my thick skull as fast as I can (what's a leaf?). For the time being could you dumb it down a bit for me please? lol.....I am just trying to get some basic theory down right now (ie. decoupling). I greatly appreciate you taking your valuable time for your responses though. Thank You.

I thought it would help in both isolating the CR and keep the comfort level up by not having your feet on the concrete.

If you have a concrete floor, it most likely does not need any more isolation, especially if you say that isolation isn't a real concern for you. Acoustically, a concrete floor is great, so you could just leave it like that, or if you think it is too ugly you could stain it, or lay laminate flooring on top of it. The general rule for good acoustics is that you want a "hard" floor (concrete, wood, etc.) and a "soft" ceiling (some form of insulation up there).

The walls will likely be 2x3 wood studs staggered on 2x6 top and bottom plates.

2x3 probably isn't enough. There's a lot of mass that you need to support, and you also don't want the studs to be too flexible. Probably 2x4 would be a better bet.

I am slowly cramming all this new info into my thick skull as fast as I can (what's a leaf?).

It does take a while to get your head around some of this stuff! A "leaf" is just an envelope of something dense, such as drywall, plywood, MDF or something like that, supported by studs / joists, completely surrounding your room. In simple terms, if you think of an ordinary house wall, there is a "leaf" on each side of that. You have studs holding it up, and drywall on each side, which is the two leaves. so that would be a two-leaf wall. If you nail another layer of drywall directly onto one side of that wall, then it is STILL only a two leaf wall: all that you did was to make one of the leaves thicker and more massive. So you could have, for example, 3 layers of drywall on each side and it would still only be a two leaf wall. Each layer of drywall that you add helps a bit with sound isolation. However, if you build another stud frame say an inch away from that existing wall, and put drywall on one side of those new studs, then you now have a 3-leaf wall, which is a bad thing. Contrary to what common sense tells you, adding that third leaf will actually not make your isolation better, and will in fact make it worse for low frequency tones. Not intuitive at first glance, but fact nevertheless. The reasons are a bit complex, and I don't want to confuse you more at this stage, but there are solid reasons based on physics and mathematics as to why that happens. So you never want to have a 3-leaf wall if you can help it. There are things you can do to help if you have no choice and MUST build a 3-leaf wall, but it is far better to avoid that if you can. The problem with adding extra layers of drywall to an existing ordinary house wall is that it helps a bit, but not much, because the studs themselves, inside the wall, directly link the drywall on each side. So when sound waves on one side make the drywall vibrate, that makes the studs vibrate, which in turn makes the drywall on the other side vibrate, so the sound actually travels right through the wall. The solution is to "decouple" the wall, basically by slicing it lengthwise down the middle, so that there is no direct connection from the inside "leaf" to the outside "leaf". Of course, you can't actually slice a wall like that in practice, so what you do instead is to have two stud frames, and put only one leaf on each frame. So if you have an existing wall that you want to isolate, your best bet is to take the drywall off one side of it, build a new frame about an inch away, and put the drywall back on that second frame. Now you have a fully-decoupled 2-leaf MSM wall, which is the absolute best way to isolate a studio at low cost. "MSM" stands for Mass-Spring-Mass, which you also sometimes see incorrectly as "MAM" (Mass-Air-Mass). The two "M's" refer to the two leaves (since they have plenty of mass), and the "S" refers to the air gap between the two leaves, which should be filled with insulation, such as rock wool or fiberglass. See? It ain't so hard to figure out!

For the time being could you dumb it down a bit for me please?

Was that dumb enough? :)

I am just trying to get some basic theory down right now (ie. decoupling).

Decoupling just means separating things physically so that there is no mechanical connection between them. It could refer to separating two sides of an MSM wall, or separating speakers from their stands, or separating a drum kit from the floor, or many other things, but the basic concept is that you cut all hard mechanical ties and replace them either with air or with "resilient" mechanical ties. For example, it's really hard to make your speakers float on air ( :shock: ), but you can mount them on something soft and bouncy, like acoustic foam, some kinds of rubber, etc. That would be "decoupling your speakers". Etc. - Stuart -

WOW, that was awesome Stuart. Exactly what I was looking for and I understood it. Thank you so much!!!! It explained a lot about what I was reading in other threads. Not having to do anything to the floor but tear up the ratty carpet is pleasing to the budget. Which right now is zero, but when we actually start gathering tracks, that money will be rolled into the project. I will look for something to keep my feet off the floor and toasty....the musicians can bring their own...lol. I will get some dimensions of what I have to work with....3 of them are fixed, the room can be adjusted lengthwise if needed. 2 of the walls are common to another business, they will have to be treated so they are not disturbed next door. Right now it is full of assorted "stuff" that I have to get the "boss" (pretty laid back guy, cool, good musician, more of a mentor and friend) motivated to get moving on. Ceilings......all of the ceilings through out the place are open 2x10's (I think) and the roof sheathing on the top of it. There are a couple of beams that go perpindicular to the joists, and there is a slope in part of it....will get to that when needed, but for now..... I understand that the CR walls should not be attached to the existing ceiling, correct? What to do at the top of the walls so the sound does not go over the wall? The 2x10's will be creating a series of tunnels right over the CR ceiling. Thanks again...I am enjoying learning.

oh...and.....if your leafs (leaves?) are different densities is that better? I am thinking they would be less prone to sympathetic vibrations that way. How about being unparallel? Seems many of the plans in John's book have that. Perhaps the inner CR wall verticle and the outer leaf (ha, using it in context already) being more of a K shape, canted out on the top and bottom, verticle only for the height of the window. K shape facing the live room. Would that help softening the corner to the ceiling and floor? Am I correct in assuming that those 90° corners are bad for building up standing waves of bass frequencies?

oh...and.....if your leafs (leaves?) are different densities is that better?

Well, kind of. For three leaf, the recommendation is to put as much mass as possible on the middle one, but for a two leaf wall the optimum design has the same amount of mass on each leaf. You can vary it a bit if you have to. Since you got the "dumbed down" version easily, I'll go one step further to help you understand it better. An MSM wall is a tuned system. It is designed to resonate at a certain frequency. If you happen to play the exact note that it is tuned to, it will sing along with you happily, vibrating and resonating very loudly, and in fact AMPLIFYING that note, and transmitting it though to the other side wonderfully! So that must have you asking: "Why would you do that? If the wall is supposed to isolate, then when make it so that it amplifies?". The secret is that you tune the frequency of the wall so low that it is below the range of human hearing. So it will only amplify frequencies that you can't hear. That won't be good if you happen to be a whale recording whale songs in your whale studio, but for us ordinary humans, it is great. So, it is tuned to one specific frequency. Actually, it's kind of like a parametric equalizer that you tune to one note: it lets that specific note through but blocks all others. It's the "blocks all others" part that we are interested in. BECAUSE it is a tuned system, it makes a great way of isolating studios. It only passes that one frequency (and a small range of others around it), but it blocks all others. Technically, it is a bandpass filter. It is based on a principle of physics that is commonly called "mass-spring-mass". Basically, you have a mass hanging from a spring that is attached to something else massive. If you pull down on the lower mass and let it go, it will start bouncing up and down at its natural resonant frequency. If you try to make it bounce at another frequency, it will resist you and refuse to bounce. Or think of a pendulum, which is a weight swinging on the end of a string. Give it a slight nudge, and it will happily swing back and forth at its resonant frequency until the cows come home, but try to make it swing faster or slower, and it will not. It will fight back, and not swing at all. Try it: Hang a bottle of coke from a piece of string about a meter long, and see what its natural swing frequency is. Now do your best to make it swing at three times that frequency. :) Good luck with that!!! An MSM wall is the same: It wants to resonate at its one specific tuned frequency, and does not want to resonate at any other. It turns out that, from the resonant frequency and up to a frequency of about 1.4 times higher, an MSM wall is a really lousy isolator, and actually helps sound get through the wall. But above 1.4 times the resonant frequency it starts to isolate, and at twice the resonant frequency it is isolating reasonably well. From there on, the higher you go, the better it gets, all the way up the entire spectrum. So obviously the key is to design the wall so that the resonant frequency is as low as possible, and at least half of the lowest frequency that you need to isolate. So, for example, if you want to isolate everything below middle C (roughly 260 Hz) then you would design your wall to have a resonant frequency of 130 Hz (which is also C, but one octave lower), and your wall will be a lousy isolator up to about 182 Hz (F# below middle C), but from there on it will do an increasing good job. And of course, if you want to isolate the entire audible spectrum, then you'd tune your wall to something below 10 Hz, since the lowest audible frequency is 20 Hz. So how do you "tune" your wall? There are only two major parameters to consider: The mass in each leaf, and the distance between them. The "distance" basically determines the "spring" part of the equation. Acoustically, air is a really good spring. You don't normally think of air being "springy", but it is. Especially if you happen to be a sound wave! So the resonant frequency of your wall is set by how much mass you have on each leaf, and how big the air gap is between the leaves, period. Want a lower frequency? Increase the mass, or increase the air gap! Or both. Simple! :) There's an equation you can use to figure out what the frequency will be for any given combination of masses and air gaps, but there are also certain rules of thumb for folks who don't like equations: A single layer of 5/8 drywall on each side of a 4" air gap will get you reasonably good isolation for most instruments, except for the bass guitar and the drum kit (and other things that put out lots of low frequency energy). Two layers of 5/8" drywall on each side of an 8" air gap will take care of those too, pretty well. If you want overkill, go with three layers of 5/8" on each side of a 12" air gap, and you'll be good even for the huge deep rumbling of cannons and spaceships. That's about all there is to it, really! OK, just kidding! It's a bit more complicated than that, but that's the general idea. More mass buys you more isolation. A bigger air gap buys you more isolation. Decoupling buys you more isolation. Don't go less than 4" for an air gap, and don't use any drywall smaller than 5/8", and you'll be fine. Frequently we get people coming here telling us that they plan to use 1/2" drywall over a 1" air gap, and they get all snooty when we tell them that it wont work: Sometimes they go off in a huff, because the think they know better than the laws of physics, but some do stay around, learn, and end up building great studios. I often wonder what happens to the guys who leave and don't ever post the photos of the "wonderful" studios they built with 1/2" drywall... :) Do the math for that 1/2" drywall over a 1" cavity, and you understand why its a really bad idea: that wall won't isolate well even in the mid range! You'll hear people just talking on the other side of it, very clearly.

How about being unparallel?

All that does is change the resonant frequency along the length of wall. You'll have a range of frequencies, starting from highest at the thinnest air gap and running down to lowest at the biggest air gap. But your entire wall is only as good as its weakest part, so what you'll get is that the wall will act more or less as if it was tuned to the highest frequency (thinnest gap). So if you want to do that, make sure your thinnest part is already at a low enough frequency.

Seems many of the plans in John's book have that.

Yes, but that is for other reasons, that we'll go into in the next lesson! 8) (And also takes into account that "thinnest gap=weakest link"). Also, don't get confused with the ISOLATION of a room, and the TREATMENT inside it: They are two different things, but they often look similar on the plans...

Am I correct in assuming that those 90° corners are bad for building up standing waves of bass frequencies?

Yup! Which makes them an excellent place for putting bass traps! In fact, all modes in a room terminate in corners, so that's why you'll see a common recommendation here that the absolute best place for your bass traps is right there, where two or three surface all come together: You are guaranteed of hitting the mode, plus you get a free boost in effectiveness in the corners. - Stuart -

You're awesome Stuart! OK, I get the MSM, tuned wall concept. I have played with those little yuppie swinging ball sets before...lol. I would almost bet there is a calculation that is going to scare me for figuring out the resonant frequency of a wall. I have some construction knowledge (jack of all trades, master of none), and I am thinking that a product like QuietRock would be optimal for sheething mat'l for the walls. According to Mike Holmes (big name in the building industry in Canada) each sheet is like putting up 4 (or is it more?) sheets of regular drywall for noise performance. I think it is super dense drywall. I am now thinking 2 seperate 2x4 studded walls will be better then, with an air gap between them, in a 2 leaf system. After all, I really only have to build the end wall. Our "big room" has an alcove on it that I will be using. Right now it is full of junk and it has a small bathroom in back. One side wall is 12" of triple brick that abuts the retail space of the same business. The other side abuts a flower shop, we definitley do not want to disturb them. I will try to get some pics and dimensions in the near future. I have sketch up, but I am really bad at it. Wall insulation????? That is the next question....I am thinking Roxul brand Safe n Sound fire proof acoustic celulose batt insulation. I am assuming (again) by what I have seen with the builds in the forum that tuned walls are not just hollow. The other thing that has me scratching my head it the open joist roof system throughout as it makes tunnels over the CR. I mean, it is great in the big room, open 2x10's on top of that is the roof sheething, on top of that is the roofing (layers of torched on membrane I think....lots of weight). But the room sounds pretty good (there are some bass traps in the corners, have not given them a big inspection, but the room works and sounds good, so I am just sticking to the CR for now). The boss is really balking at the idea as he has the present booth all on dedicated circuits for wiring and is thinking cost, but I am slowly encouraging him and will be doing most of the work. I told him it does not cost anything to clean out the room to start. This will likely end up a long project, as we have to start getting money coming in to afford it, and word is just starting to get out. He has a guy coming in every week to tutor me on the new DAW and we cannot stand side by side in the present CR. We have both the DAW and a Mackie 1604 and I want a table we can set them on side by side, that way I can use both for live shows. Our starting venture is to have people come in and play to a live audience, as they play, we gather the tracks and hand them a CD of wav files they can take home and throw on their computer and mess with it from there, or send out to mastering, etc. Gets music into the community in exchange for tracks. We operate on a donation basis right now and the bills get paid, but that's about it. I am doing what I am doing in exchange for the training I am getting. Slowly, we want to build it into something that will support itself better, but still keep getting the music into the community by giving fans and musicians a venue that is affordable. We still want to put out a good product.

So, here is the reason I want a new CR.....This is what I am working out of now. The Mackie board resides under the DAW. Ok, do I hear snikering?

This is what I am working out of now.

:shock: :shock: :shock: :shock: :shock: Oh wow! No wonder you are so keen on getting a decent room! I feel for you. It must be hell to try to get a mix that translates anywhere at all in that space! I've worked in some unusual environments in my time, but I reckon yours takes the cake... Whew! - Stuart -

I looked at the room I wanted to take over. Well, as much as I could anyway. I am rethinking after taking a few rough measurments (hard to weave a tape through all that is piled up in there). The room has a lot going against it. First, it is about 13' wide and 16' deep, but there is a bathroom that takes up about 3' at the back for part of the room. This is getting the room pretty square. The ceilings are low. The floor is over a basement and there is the access way to the basement in the floor. There is a wall between it and another business that cannot be disturbed. So, I am back to trying to figure location again. This time somewhere in the "big room". As I have mentioned, it used to be a courtyard that developed by other buildings going up around the area. BUT!! The floors are a solid foot of concrete. It is about 40x40 but has an area divided off for a small woodworking area. The walls that surround it are foot thick solid triple brick. Here is a tour of the place. beside the CR is the entrance to the big room: looking through the door into the big room (note carpet, not my fault), the door between the piano and stage goes to the shop: and panning to the right, it shows our heat source too (forced air NG), we just shut it off when recording: Looking back at the entrance door and CR window, the door to the far right is the room I was originally thinking about. Shows one of the bass traps in the corner (again, not me, have not even inspected them yet, I just got here): A few posts to deal with, as you can see. It must remain useable for live performances. Is there any point in posting pics of the room I was thinking of useing? Can a room such as I described be made into a CR on a budget? Right now I would not mind just a coat of paint on the place in a bit more of a bright colour. Note the ceilings as mentioned earlier. Thanks for any input/comments. Given the circumstances of budget and inexperience (mine), I am really lost on what to do. Right now I am still learning the sound engineering end of it, and trying to go through John's book and get some of that info absorbed. But I am enthusiastic and willing (wanting) to learn.

post the photos and detailed measurements of the other room. i think it would be hard to get one room optimized for live performance and critical listening. even with the smallness of the other space, it might be possible to shape it so it works.

OK, a few shots, for what they're worth. As you can see, a lot of mucking out has to be done first. I guess this room is the only choice available. After it gets cleaned up, I will get some info and measurements and try to make a SU of the room. I will also be doing some studying (and asking questions) so I can address the challenges specific to this room. This is looking through the doorway to the bathroom door in the back. The left wall is 12" of brick and abuts our own space. To the right, not sure what the construction is but beyond that is the flower store I don't want to be disturbing. inside the door looking left: looking right: and looking back at the door from the bathroom doorway in the rear: I did say it needed cleaning out first, didn't I?....lol. I may be able to move the entrance wall out, to be determined. The bathroom may be reconfigured, will take that into account in the design. The room will also have to have some capacity as storage space. Do the main side walls that I see in most booth designs have to be fixed solid structure, or can they be sliding panels? I was thinking that if I could use sliding panels, I could use that in incorperating storage behind them. Would anti-fatigue mats be good under a laminated floor (on top of the wood floor over basement) for isolation/insulation? (general question, I don't have the construction specifics yet of what is there) Specifics will come as soon as I can get them. Thanks Jim

in theory, some portions of the side walls and elsewhere could be cabinets to store mics etc. it will be useful to get really accurate measurements (1/4" / 5mm or so) of the room.

OK, Thanks. I guess the next step is to get the boss motivated to schedule a day of clean up! Then I can more accurately describe what is going on. Everytime something gets moved in there, I see something different. More concrete on the floor than I had seen before, that's one good sign. We are in the middle of putting together a bunch of tunes and recording while I learn the engineering end. Having a blast doing it (boss must like what he is hearing, he is really keen on the project), will be great to have a comfy room for the board where I can sit and work.

A long day doing some preliminary mixing today.....have some "ear fatigue". But had a blast too. Anyways, I was talking to the boss today and the room (in the above pics) that I get to adapt to a CR has a false ceiling (it is still not cleaned out). The good news is the ceiling is 3' higher than the pics show......The bad news.....there is virtually nothing between it and the flower shop next door. I have to say that the big cheese is a pretty cool guy, but a little old fashoin when it comes to acoustics (thinks it is some sort of voodoo or something). As there is zero budget right now, that is not a problem, but I think I am going to have to build the CR a bit at a time. First, isolating from the flower store, then a bit at a time, maybe start with a cloud, absorbers at the reflection points on the walls(I like the super cheap ones built in another thread with the 703), maybe a few bass traps, and just go a bit at a time as we go along. It will be fun picking your brains as we go....have patience with me, and thanks again!! Jim