Hybrid Studios - SketchUp Design

Hey guys, I've been a silent fan of the forum for some time now and am looking to get some opinions on our design. We are planning on starting up a multimedia studio in Southern California, having a control room, 2 iso rooms, and a large live room where we can do green screen filming/photography. In the SketchUp file, our warehouse is the black rectangle on the ground. For our wall construction we were planning on doing double wall construction. 2x4s stuffed with Ruxol stone wool, mlv, then r channels and 5/8" drywall. We are still trying to figure out what walls will be fabric vs drywall. Thoughts on design, wall construction? EDIT: Our SketchUp file is too big for this forum, but you can download it by copying and pasting the following link in your browser, or right click the link and choose "Saved Linked File As". http://kleinaudio.com/Hybrid-Studios.skp

Hi "Hybrid Studios". Please read the forum rules for posting (click here). You seem to be missing a couple of things! :)

For our wall construction we were planning on doing double wall construction. 2x4s stuffed with Ruxol stone wool, mlv, then r channels and 5/8" drywall.

Forget teh MLV, unless you have money to throw away: what stops sound is mass. Mass is mass: sound waves don't care how much you paid for it. While MLV is massive, and will stop sound, it is a very expensive way of doing so. If you want to save money, then just use the cheapest mass that will do the job. In most places on this planet, that turns out to be plain old 16mm (5/8") fire-rated drywall, although there are some places where other things might be cheaper, kg for kg. Also, you seem to be using a proper decoupled 2-leaf MSM design for your isolation, with each leaf on its own stud frame, so you do not also need RC. If your walls are decoupled, then they are decoupled, and it makes no sense to decouple them twice. Wasted money. RC is for people who cannot decouple by building separate frames. In your cae, you do show separate frames, so RC is pointless.

We are still trying to figure out what walls will be fabric vs drywall.

If it is fabric, then it isn't a wall! In order to isolate you need mass. Walls have two leaves, and each leaf consists of drywall. Fabric is not used to isolate rooms: it is used to hide the treatment inside the rooms. So build each room as a stud frame with drywall on it: that is your isolation. Then inside the room, you add whatever treatment is needed by the room. Isolation and treatment are two entirely different, unrelated aspects of studio construction. First you isolate, which stops sound going out. If sound can't get out, then it must stay in. If it stays in then it makes the room sound bad, so you add treatment to make it sound good again.

Thoughts on design, wall construction?

Two-leaf, fully decoupled MSM. That is the most effective, most economical way to get good isolation: There are other ways, but they are either less effective, or more expensive, or both. But you have other issues in your design, apart from the walls. Your floor, for example, appears to be built as a resonant drum head: three layers of wood (?) on top of a 2x6 (?) framework. That will make a wonderfully resonant cavity, that will act something like a drum, severely damaging your isolation to whatever is underneath all that, and also wreaking havoc on your room acoustics, since it will suck out energy at whatever frequency/frequencies it is tuned to. Why do you need that raised floor? I see conduit under there, but there are other ways that you could handle your cabling that would not interfere with your isolation or your acoustics. Then there is your front wall: It seems like the original idea was to have speaker soffits in an RFZ based design, which would have been great, but then something happened and now you have that strange heavily angled front wall thing, that looks like it might have been part of an CID design, but looks like it will be a perfect reflector at your first reflection points, and will therefore cause large phasing, comb-filtering, interference, timing and other unpleasant artifacts. I would get rid of that, ar at least re-angle to a proper RFZ design, and go back to the flush mount concept too. There seems to be enough space to do that, even considering the two windows to the iso booths. Also, if you are going to be doing film work, video-post, sound-for-video, and similar, then I'd really suggest that you should at least one large video screen up front somewhere. Where is the video control room / NLE suite going to be in relation to your audio control room? That's important, too. Then there is the sample of isolation materials on the wall between the two iso booths: If you are going to use 1/2" steel plate for your isolation, that will be fantastic (very expensive, but great isolation!) However, in that case it is pointless to add the 5/8" drywall and the MLV: Their mass is absolutely insignificant compared to the half inch steel plate, that they won't have any effect at all on isolation. The steel plate by itself will be way more than enough. In fact, it is very much overkill, unless you have really huge isolation needs. How much isolation do you need between those rooms? Is steel plate really necessary? The expense is huge. Finally, all of your timber is sized very strangely: For example, your 2x4s are shown as measuring 2 inches by 4 inches, and your 2x6s are show as being 2 inches by 6 inches: While you probably can buy wood like that, it would be cheaper and easier to just get normal 2x4s. Is there a reason why you need special sized timber? Is that all you can get where you live? There are a few other issues that also need looking at (if you use 1/2" steel plate for isolation, then you will need glass that is much thicker than 1/2" to maintain the same surface density, the ceiling is strange too, with joists dropped from joists on spacers, etc.) but I'd start by working on your isolation shell, room shapes, dimensions, and layouts first. - Stuart -

Thanks for the detailed reply and sorry about the posting rules. I'm glad I have come looking for criticisms haha. It's good to know about MLV and RCs, as well as the angled walls. So basically you think the best way to go is double drywall with green glue (or is there a better spring)? What are your thoughts on QuietRock? Do you think the benefit would be worth the price? Also, what are your thoughts with a double layer of drywall and insulation, do you think stone wool would have a greater benefit vs standard R-30/R-15? As far as the angled walls go, we will have to re-visit what would be the best possible design. We are planning on having the monitors on a bridge behind the mix desk, so do you think that having the front wall just straight would be better? My apologies about the sketch up design, but the steel was just a texture place holder for the MLV, but since that no longer appears to be cost effective, we will change it out. And I hope I'm not totally putting my foot in my mouth, but isn't a 2x4, 2in x 4in x 12ft or 10ft etc.? It seems as though floating a floor is also a bad idea, what is your preferred flooring method? Rubber matting? The Sketch Up design is just showing our warehouse space, the gray box by the door leading into the control room is attached to our front office area. This is where we were planning on adding an editing bay or two (video monitor included). Thanks for you thoughts and criticisms so far, I hope that I'm not overloading you with questions. If I can provide clarity on anything please let me know. Again thanks for your time! -Bill

So basically you think the best way to go is double drywall with green glue (or is there a better spring)

Well, "yes but no"! I guess I didn't explain things too well, since you seem to have a misunderstanding about some things. First, Green Glue is not a spring: it is damping between layers of drywall on the same leaf. Air is the spring. The air between the two leaves of drywall, which is not the same as the layers of drywall. So yes, you need "double drywall" in the sense that you need two "leaves" of mass separated by a large air gap, with each "leaf" normally consisting of a stud from with one ore more layers of drywall on it. So your "outer leaf" might be a stud frame with just a single layer of drywall on it, or two layers of drywall (directly on top of each other, on the same side of the frame), or maybe even three layers of drywall in extreme cases. And your "inner leaf" would be something similar: a stud frame with one, two or three layers of drywall on it. And you might, or might not, also decide to use Green Glue in between some of those layers of drywall. Green Glue helps to damp some types of resonance in the drywall layers.

What are your thoughts on QuietRock? Do you think the benefit would be worth the price?

Mass is mass, and sound waves don't care about the price tag. They react to the mass that they run into, regardless of how badly that mass affected your cheque book. There are no "magic" materials that bypass the laws of physics (despite what some manufacturers try to get you to believe!). So take a look at what QuietRock is made of, and compare its cost with the cost of other equivalent materials that you could use to get the same effect. If it turns out that QuietRock is cheaper for the same effect, then go with QuietRock. If it turns out that other materials are cheaper for the same effect, then go with the other materials. I can't say straight out which way it will work out for YOU, since prices vary all over the planet. But in general, for most places, the cheapest materials that does the job is plain old fire-rated 5/8" (16mm) drywall.

Also, what are your thoughts with a double layer of drywall and insulation,

You should always use insulation in the wall cavity between the two leaves. It lowers the MSM resonance point, damps other types of resonance in the cavity, and in general improves isolation considerably.

do you think stone wool would have a greater benefit vs standard R-30/R-15

You can use either mineral wool or fiberglass insulation, provided that you use the right density in each case. For mineral wool, it should be around 50 kg/m3, and for fiberglass it should be around 30 kg/m3.

As far as the angled walls go, we will have to re-visit what would be the best possible design.

There are different opinions on what the best possible design for a control room is, but the general consensus these days seems to be that RFZ and CID are two really good options. RFZ stands for "Reflection Free Zone", where the concept is that the room itself is shaped so that no first-order reflections can get to your ears until 20 ms after the direct sound gets there, and even then the level should be 20 dB lower. So surfaces at the front of the room are angled such that they reflect sound past the engineer, not towards him, and send it to the rear of the room, where it hits heavy absorption, or diffusion if the room is big enough, to remove as move energy as possible before that reflected sound eventually gets back to the engineer's ears, very much attenuated and diffused. CID or "Controlled Image Design" is similar, sort of an extension of RFZ, involving multiple angled surface at the front and sides of the room, and more complex to calculate and implement. Personally, I like RFZ, since the concept makes so much sense, and it works so darn well in practice. RFZ is more or less the shape that you show in your initial model, but usually with the speakers flush-mounted in the front angled walls ("soffit mounted"), in order to eliminate those nasty first order reflections off the front wall, as well as extending the low-frequency response of the speakers, greatly tightening the bass, improving the stereo imaging and sound stage, eliminating several other common artifacts, and in general making the room and speakers sound as good as they possibly can. There are methods for determining the optimum angles for those walls, as well as for the geometry of the speakers, soffit, desk and listening position.

We are planning on having the monitors on a bridge behind the mix desk,

That's not a good idea: many people do that because they see it done in professional studios, but they don't understand the reasoning. Pro studios put their main speakers in the walls (flush mounted, as I mentioned above), and do all their mixing and critical listening on those. Then they switch to the cheap, lower quality speakers, badly mounted on top of the bridge, to "check the mix" and see how it would sound on a typical home stereo system with bookshelf speakers. So those "speakers on the bridge" are not their main speakers, and are general never used for tracking or mixing: they are just there as a final check, to make sure that the mix that was carefully crafted on the high-quality soffit-mounted mains, also sounds good on low grade, poorly set up speakers. If you mount speakers on the meter bridge, then they cause the meter bridge itself to vibrate, thus distorting the sound. The location on the bridge also generally causes reflections from the console and desk, and a whole bunch of associated artifacts, such as comb-filtering, phase cancellation and other nasties. So if you want highest quality sound, your main speakers should be soffit mounted (flush mounted) in the front angled walls, and correctly set up with the optimum geometry.

so do you think that having the front wall just straight would be better?

It is an option, and some people do that, but of course then you cannot have soffit mounted speakers. Personally, I think the gains offered by correctly mounted speakers in an RFZ design is the best you can get.

And I hope I'm not totally putting my foot in my mouth, but isn't a 2x4, 2in x 4in x 12ft or 10ft etc.?

When lumber is cut at the mill, it really is 2" x 4", but it is then dried and shrinks somewhat. When you buy a ' 2x4 ' in your local Home Depot or Lowes, it actually measures 1-1/2" by 3-1/2". A 2x6 measures 1-1/2" by 5-1/2". A 2 x 8 is actually 1-1/2" by 7-1/4". Etc. So the nominal dimension is not the actual physical dimension. However, you can also order true 2 x 4's if you want, which really do measure 2" by 4", but that is usually not a stock item, and must be special ordered. Confusingly, the length really is correct: So a 12 foot 2x4 actually is 12 feet long, even though the cross section is only 1-1/2" by 3-1/2".

It seems as though floating a floor is also a bad idea, what is your preferred flooring method? Rubber matting?

What is your current base floor made of? Concrete, hopefully? And sitting directly on the surface of Planet Earth? If so, that's a great surface, acoustically. If you don't like it aesthetically you could stain it, polish it, or just lay laminate flooring on it, or solid hardwood flooring, or ceramic floor tiles. There are several options, but the idea is to keep it hard and reflective, so that you can have a "soft" ceiling, and also increase your options for final tweaking of the acoustics, after the room is finished.

the gray box by the door leading into the control room is attached to our front office area. This is where we were planning on adding an editing bay or two (video monitor included).

OK, so you won't actually be doing any "sound for image" work in this studio? That will all be done in the editing system? The reason I'm a bit extra-inquisitive here, is because video post is sort of my area of specialty: designing video post production facilities is what I've been doing for the past twenty years or so, so even though it has nothing at all to do with the isolation or acoustics of your audio studio, I still get curious and love to see what people are doing in different parts of the world! So it's more just my own professional curiosity than any real need to know in order to help with the audio part. Sorry if I'm overly curios there! :oops: But it's unusual to see an audio control room that is not going to be doing sound-for-image work, located right next to a chroma-key set, and with a big window right onto the set. Just piqued my curiosity a bit. Anyway... excuse my prying!

I hope that I'm not overloading you with questions.

Nor problem! That's what this place is all about: helping out people to improve their studio designs. :) Nice SketchUp work, by the way: You grouped your geometry logically, and made it easy to figure things out, and look at different layers and parts of the design simply. I'd suggest you start using layers and scenes as well, to make it even easier... :) - Stuart -

Hybrid Studios wrote:

... We are planning on having the monitors on a bridge behind the mix desk...

Possibly Stuart misunderstood what you mean't here - or perhaps I misunderstand. I'm assuming you mean a separate, stand-alone construction serving as a support for your monitors, and not the "meter bridge" common in many studios with large mixing consoles, as Stuart understood you. I also have my Nearfield monitors on a separate "bridge" - the video monitors are also affixed to this (via swivel arms clamped to the bridge) - thus it is truly a "monitor bridge". Important here is that the speaker cabs are well, physically decoupled from the bridge to minimize conduction of vibrations (resulting in a secondary propagation source as well as detrimental interaction ("crosstalk") between the monitors resulting in poor or muddled imaging. Also the support structure for the bridge should be good and heavy as recommended generally for monitors stands. All said, if your budget and KH allow it, an RFZ design with soffit mounted monitors a Stuart described would be worth serious consideration.

When lumber is cut at the mill, it really is 2" x 4", but it is then dried and shrinks somewhat.

They also plane the lumber to make it smooth and consistent in size, which makes carpentry much easier :cop:

Stuart and Brian thanks for all your critiques! It is truly appreciated, sometimes a little hard to hear haha. Brian has a better idea of what I was talking about with a separate independent monitor bridge; and I definitely hear you on the soffit mounted speakers, but am planning on moving away from that just to save some money and keep construction a little simpler. Stuart thanks for taking the time to explain so many things to me! It seems in regard to the MSM idea, I was a bit off. Thanks for re-explaining that to me. It also looks like QuietRock is not the most effective way of increasing my wall's STC. I was planning on using Roxul's stone wool insulation (http://www.roxul.com/residential/produc ... fe'n'sound™). Our floor is indeed concrete and after taking your advice into consideration, we are leaning toward a hardwood floor. Do you think the best strategy for the floor is to just lay the hardwood floor on the concrete? Or add a rubber mat between the concrete and hardwood floor? For the control room, I was now planning on sound proofing the outside rectangle frame, then going back in after and adding lots of absorption behind the monitoring bridge and diffusion to the back of the room. I was totally wrong with the dimensions of the wood and am showing my experience with construction haha. My biggest concern is getting our live room walls to have a high enough STC, where our neighbors won't be irritated by a drummer blasting away in there all day. Our buildings warehouse walls are unfortunately drywall (I wish it was concrete :cry: ) and these are the walls shared with adjacent warehouses. Basically in your guys opinion, would a single wall built in front of these shared walls with a 1 or 2" gap, stone wool, layer of 5/8th drywall, green glue, and then another layer of 5/8th drywall give me high enough STC? Should I include a layer of MLV within the layered construction? Don't know if the benefit will be worth the cost. Let me know if I can provide any more information let me know, again thanks so much for your time and the information!

Our floor is indeed concrete and after taking your advice into consideration, we are leaning toward a hardwood floor. Do you think the best strategy for the floor is to just lay the hardwood floor on the concrete? Or add a rubber mat between the concrete and hardwood floor?

I'm not an expert on flooring, so I don't even know if if you can lay hardwood on rubber. If that is possible, then you could try it, I guess! Another option is laminate flooring, which normally is laid on some type of resilient underlay. Some that stuff can look really nice.

then going back in after and adding lots of absorption behind the monitoring bridge and diffusion to the back of the room.

Your room might not be big enough to be able to use most types of diffusion successfully. You need a lot of space between your ears and the diffuser, in order for the artifacts created by the diffuser to even out and become smooth, and that also depends on the frequency the diffuser is tuned to. Depending on which expert you listen to, you need either ten feet, or three full wavelengths of the lowest frequency, or seven full wavelengths of the lowest frequency. Personally, I reckon 3 or 4 full waves is probably good, so measure the distance between the front surface of the proposed diffuser on back wall and your ears, multiply that by four, and that gives you the lowest frequency you can tune your diffuser to. However, there is now evidence that the scattering effect of diffusers can extend a full octave below the calculated low cutoff frequency, so when you come up with the number from your measurement, better double the frequency to be sure. Then if that final frequency is any use for the rest of the acoustics in your room, it makes sense to build diffusers. On the other hand, if the frequency is too high to be useful, then just go with absorption. Your plan also seems to be skipping the first reflection points: Those are rather important.

My biggest concern is getting our live room walls to have a high enough STC, where our neighbors won't be irritated by a drummer blasting away in there all day.

Another thing you ain't gonna like: STC is a lousy system for measuring studio isolation, since it does not cover low frequencies! It can tell you nothing at all about how well a wall isolates a bass guitar, for example. It can tel you lots about how well it will isolate normal speaking voices, but not so much about music. It was never intended for that purpose. There are other methods used for measuring isolation for studios, but looking at the full TL (Transmission Loss) is the best, I think (others might disagree... )

neighbors won't be irritated by a drummer blasting away in there all day.

An enthusiastic drummer can put out 115 dB without breaking too much of a sweat, and a bit more if he really tries hard. So that's your starting point for figuring out how much isolation you need. Now all you need to do is to define the objective level equivalent to "neighbors not irritated"! :) There are a couple of ways of doing that. If "neighbors not irritated" is the same as "cops can't legally arrest me or fine me", then check the noise ordinance regulations at your local municipality, to find out what the legal maximum level is, which is normally different for daytime and nighttime. If you really want to keep your neighbors happy, then a better method is to play drums loudly on a full range system set up in the actual space that you will be using, then take a sound level meter over to your neighbors place and get someone else to turn down the volume on the system until your neighbor says he is not irritated, and measure that level on your meter. Either way, subtract the "not irritated" level from 115 dB, and the result is how much isolation you need. Simple! :)

Basically in your guys opinion, would a single wall built in front of these shared walls with a 1 or 2" gap, stone wool, layer of 5/8th drywall, green glue, and then another layer of 5/8th drywall give me high enough STC?

depends on how that existing wall is built: if it is a typical stud frame with drywall on both sides, then that is already a 2-leaf MSM wall, so adding anything else next to it create a 3-leaf wall, which is always going to give you WORSE isolation for low frequencies than the equivalent 2-leaf wall. In that case, what you can do is to take off the drywall on your side, use it to "beef up" the other side from within (between the studs that will now be visible), then build your second leaf as you described. If you do that properly, you should be able to get isolation in the range of 50-something dB, meaning that the 115 dB drums will be down to about 60 dB just outside the wall. That might or might not be good enough, depending on how easily your neighbors are irritated...

Should I include a layer of MLV within the layered construction? Don't know if the benefit will be worth the cost.

Not worth it. MLV is just mass with a very expensive price tag: It does have some uses in acoustic isolation, but not many. I just used it in the ceiling of my dining room to isolate the soil pipes from a new bathroom I built, and it works fine for that, but the ONLY reason I used it is because I needed something heavy and flexible that I could wrap around the pipes, as I didn't have enough space to build a soffit for the pipe: It's difficult to wrap drywall around a pipe! But I would not have used it, if there would have been enough space to build a proper soffit, and I cried as I forked over the money for the roll of MLV ... (OK, not really, but I wasn't happy having to spend so much for simply mass). So unless you have some very special requirements, like I did, then forget MLV. Sound waves really don't care how much you paid for the mass that you used to stop them. The stop just the same if you paid a few dollars per kilogram for drywall, or a few thousand per kilogram for titanium!

I was planning on using Roxul's stone wool insulation...

That should be fine... but your link seems to be broken! - Stuart -