Building into existing shell.

Greetings. I am currently working out of a smallish home studio that was built into an existing guest house. The goal is to convert this space into a professional recording and mixing studio. The problem is that due to location we are not allowed to demolish or extend the base of the main building. After speaking with a general contractor, we've decided to completely gut the interior leaving only the shell, which is a standard 2x4 > plywood > siding affair. Once a more specific floor plan has been drawn up, we will have a structural engineer on location to be certain of the integrity of the building and work out details of the tear down. Jumping ahead to an assumed gutted shell of a building: Building Dimensions The building exterior (from the plywood) will measure approximately 41' L x 24' W x 16' H (with an additional 4' at the apex of the A-frame). This area will be split into two separate rooms - a live room and a control room that will also act as a smaller second live room. The live room will measure 19' L x 21' W x 15' H and the control room will measure 16' L x 21' W x 13' H. This leaves a distance of 1.5' from outside wall to inside wall. (The live room will have a brick or stone "live" wall 1' in from the "long" wall to improve the dimension ratio, and there will be roughly 2' of space from wall to wall between the live and control rooms for isolation, which explains the missing 3'. Thoughts on this are also welcome. I have renders I can upload if desired.) Location The property is secluded from any major roads. It is a very quiet area with the nearest neighbor being about 300' away. However, there is the occasional truck and overhead airplane to worry about. The planes in particular are propellor based and can occasionally fly fairly low, though not terribly often. Budget We have roughly $100,000 (one hundred thousand) dedicated solely to the building construction and treatment (recording equipment is a separate budget entirely). We plan to do most of the labor ourselves with the help of some friends that love music (and pizza and beer). This budget also includes the occasional fees to have an acoustician/studio designer as well as any contractors come to the location periodically throughout the process to make sure we are doing things correctly. We are limited with what we can do with the existing building, but after long consideration it has been decided that this is the best location with the lowest financial overhead for us. The location also allows a future second studio and lodging. The hope is, naturally, to come in under budget. If this can be done for half our budget, we'd all be thrilled. But it must be done correctly first and foremost. Floor Plan I've made a couple of interior renders and basic floor plans in order to get the investor excited, but now it is time to create a more exact floor plan to make sure that we are doing this properly and to start putting together a cost-of-materials spreadsheet. My hope here on this forum is to start with the basics and build up from there making whatever adjustments your collective knowledge sees fit, while getting into more detail as this project moves forward. I'll post a couple of images thus far and ask a series of questions related to those images. Then I'm sure I'll post some more. ;) Images Image Details The external wall is a sheet of plywood (not yet certain of depth), vapor barrier, and 2x4. I can't change this. I plan to remove the old insulation and add 4" of 703 (or equivalent) between the studs. Next there is roughly 4" of air space, followed by another 4" of 703. Inside of the second layer of insulation is brick, followed by two layers of drywall (with green glue). The two rooms are individually attached to their own inner wall, separate from each other, resulting in a double-leaf system throughout the complex. (The ceilings will be as well, but we'll get to that later.) I have double doors and sliding glass placed in my rudimentary floor plan and renders, but I'm not quite there on this detailed floor plan yet. It is however in my head and will be added as I move forward. No sense in adding them now if I have to change half of the plans. HVAC, fire suppression, and lighting are all considered but are outside of the scope of this introduction. I'll pick your brains on that stuff soon, I'm sure. ;) Questions Walls and ceiling: Should the insulation on the outside wall extend over the 2x4s and not simply be between them? Before adding that first layer of insulation to the outside wall, should I caulk the studs where they meet the outside plywood, or is this of no concern? With a total of 8" of insulation, would it make sense acoustically to fill the air gap, or would it be a case of diminishing returns? I've added brick (or concrete) to the inner wall to create more mass, however I run into the problem of what to do with the ceiling. I certainly can't build a ceiling from brick to equal the mass of the walls. What should be done to add mass to the ceiling? Is brick a necessary addition given my location? Again, I'm not worried about neighbors or heavy traffic, but there is the occasional overhead prop-plane to worry about. I not only wish to record loud drums and guitars, but also would like to record quiet orchestral and choral pieces, as well as some foley work. Would something like MLV be a more appropriate solution for the walls and ceiling? Should I simply triple-layer the drywall instead? The outside walls extend up to 16', where the A-frame roof starts, reaching an apex of an additional 4'. This means there will be a maximum of 5' of space between the live room ceiling and the roof apex, and 7' for the control room. Perhaps mass isn't such an issue with that much space? (There is only 1' and 3' respectively of space from the ceilings to the start of the roof.) Floor: The structure is build on a massive slab of concrete sitting directly on earth. I do not intend to float any flooring because I probably don't need it and would likely mess it up anyway. However, I would be interested in raising the floors (separately) in each room with simple 2x4 to allow for wiring to be unobtrusively delivered throughout the complex as well as to add some insulation for thermal purposes. Is this a proper solution, or could this potentially cause acoustical issues? Just to reiterate, we will have engineers and acousticians on site periodically as this is simply too much money to not do things properly. But the more legwork I can get done on my own, the lower our expenses should be. Plus I enjoy learning. Thank you so much for your assistance! I'm open to adjusting things as we go and I look forward to hearing from each of you.

Hi Jeremiah, and Welcome! :) Great first post, by the way! I wish everyone would post as completely and thoughtfully as that. :thu:

41' L x 24' W x 16' H (with an additional 4' at the apex of the A-frame).

That's a really nice sized space, especially the ceiling height. So is that 16' at the top plate? In other words, the bottom edge of the roof trusses is 16 feet above the floor? If so, that's excellent.

a live room and a control room that will also act as a smaller second live room.

With nearly a thousand square feet of floor area to play with, you probably actually have space for more rooms, if you want them. ITU and EBU specs for control rooms call for a floor area of about 250 to 350 ft2 (250 for stereo, 350 for multichannel), so you could easily afford to have a CR taking up about 300 ft, for example, a live room taking up around 550, and an iso booth taking up around 150. (Those are the total areas, of course: the actual inner-leaf floor area would be less, in each case, after accounting for the wall thickness). You could probably even go to four rooms, if you don't mind making each a bit smaller: CR, LR, drum booth and vocal booth, for example. Those ITU/EBU specs are not written in stone, and you can still have a great room with less floor area. Also, what about other rooms you might need in the building? EG, bathroom, office, lobby, green room, storage, etc. Is there any need for those, or are they taken care of in another building?

This leaves a distance of 1.5' from outside wall to inside wall.

That would be excellent if you need really high levels of isolation, but that doesn't seem to be the case, so you can probably reduce that quite a bit, to gain space in the rooms. Normally a 10" thick wall (total thickness) will do the job of getting you good isolation. That would give you another 16" in each direction: worthwhile, for sure.

The live room will have a brick or stone "live" wall 1' in from the "long" wall to improve the dimension ratio,

The stone wall is a good idea, but live rooms don't necessarily need to be based on ratios. Control rooms do, for sure, but the purpose of a live room is to have a bit of "character" of its own. So ratios aren't as important for live rooms, and you don't need to sacrifice so much space behind the stone wall just for that.

there will be roughly 2' of space from wall to wall between the live and control rooms

Here too you can reduce that quite a bit, unless you really do need very high levels of isolation. Taking that down to one foot can increase the size of either room, or both, or provide some extra space for adding one of those other rooms I mentioned.

However, there is the occasional truck and overhead airplane to worry about. The planes in particular are propellor based and can occasionally fly fairly low, though not terribly often.

It would be good to measure the actual loudness of those trucks and planes with a sound level meter, to help you decide on how much isolation you need. If you could actually record them too, that would be great, so we can take a look at the spectrum of their noise, to help with the isolation concepts: it's no use designing in massive low-frequency isolation if most of the noise is in the high end: And the inverse also applies: it would be sad to assume there is no low frequency rumble from the trucks and not design for that, then discover that it's a big problem after the place is already built. Gathering as much data as possible up front is always a good idea.

We have roughly $100,000 (one hundred thousand) dedicated solely to the building construction and treatment

That sounds about right for a 1,000 ft2 facility. That works out to around US$ 100 per square foot, which is probably reasonable, as long as you don't have unusual requirements.

We plan to do most of the labor ourselves with the help of some friends that love music (and pizza and beer).

Ahh! That makes the budget even more reasonable! Labor is a big part of construction costs, so reducing that is a smart move, provided you have the skills and tools. There will likely still be some parts where you can't skimp, such as electrical work, structural calculations, HVAC installation, and a few others, but you sure can save a lot of money doing most of it yourself.

If this can be done for half our budget, we'd all be thrilled.

Mmmmmmmm.... Well, dreaming is free! :) I reckon you can come in on-budget, but I wouldn't count on coming in much under it. There's this guy called "Murphy" who will see to that, no mater how well you plan... :)

The external wall is a sheet of plywood (not yet certain of depth), vapor barrier, and 2x4. I can't change this.

Not from the outside, no. But from the inside, you sure can change it! There's a technique called "beefing up" that you can put to good use here, to add more mass to that outer leaf. Basically, you cut strips of drywall, OSB or plywood to fit in the studs bays of that wall, pushed up tight against the existing plywood, sealed with acoustic caulk, and held in place with cleats. That can substantially increase the mass (and therefore the isolation), as well as improving the seal. It's a bit boring to do (maybe "mind numbing" would be a better description...) but it is worth it, if you are unable to do anything to the outside.

I plan to remove the old insulation and add 4" of 703 (or equivalent) between the studs.

You could also use fiberglass or mineral wool insulation in there, to save a few dimes. They key point for that insulation is the density: if you use fiberglass, then the density should be around 30 kg/m3, and if you use mineral wool then shoot for more like 50kg/m3. Those are optimum densities for damping inside MSM systems. Save the more expensive 703 for where it is really needed: treatment.

Inside of the second layer of insulation is brick, followed by two layers of drywall (with green glue).

Skip the GG and drywall there: they aren't doing anything much for you. The density of brick is around 2000 kg/m3 (depending on type), so assuming you just do one thickness for your wall (3-1/2") the surface density would be about 180 kg/m2. The surface density of 5/8" drywall is around 11 kg/m2, so you'd need about sixteen layers of drywall to double the mass of the brick, and do something useful acoustically.... IF you need more mass than a single layer of bricks can provide, then just render the wall with a 1/4" or 1/2" coat of plaster: Much more mass for much less money, effort and space.

I have double doors and sliding glass placed in my rudimentary floor plan and renders, but I'm not quite there on this detailed floor plan yet. It is however in my head and will be added as I move forward. No sense in adding them now if I have to change half of the plans.

:) From experience, you'll most likely have to change the plans many, many times as you move forwards! It's just the nature of the studio design process.

Should the insulation on the outside wall extend over the 2x4s and not simply be between them?

In between the studs is fine, but here the rule is "the more the merrier". The difference in total isolation of two identical MSM walls, where one is filled with insulation and the other has none at all, is as much as 16 dB. The more you put in, the better it gets. But your plan of 4" + 4" will likely already get you 10 dB or more, so depending on how much you need, you might of might need to fill the cavity.

Before adding that first layer of insulation to the outside wall, should I caulk the studs where they meet the outside plywood, or is this of no concern?

Absolutely yes and totally! Better buy shares in the caulk company now, as their stock is sure to rise once your rooms starts gulping down their products... :) In other words, sealing is critical to isolation. The objective is to make that outer-leaf wall totally air-tight. Hermetic. So yes, seal every tiny nook and cranny. Seal every miniscule crack. If it even looks like a crack, then seal it. Even if you are sure it is NOT a crack, then seal it anyway, just in case... Did I mention that sealing is important?

With a total of 8" of insulation, would it make sense acoustically to fill the air gap, or would it be a case of diminishing returns?

I think I already answered that, above.

I've added brick (or concrete) to the inner wall to create more mass, however I run into the problem of what to do with the ceiling. I certainly can't build a ceiling from brick to equal the mass of the walls.

Why not? :) It can be done...

Is brick a necessary addition given my location?

That depends on the answer to the single most important question for deciding on how to build your place: "How much isolation do you need, in terms of decibels?". Answer that question, and you immediately narrow down the myriad possible wall designs to just a handful. But at a guess, I'd say that no, you probably don't need brick, and you don't need such large air gaps, unless your isolation goals are extreme. Typical double-stud drywall MSM walls can get you as much as 70 dB of isolation if designed and built carefully, but more like 50 to 60 for the average home studio. That's still pretty darn good. So your first order of business should be to take some measurements with a sound level meter, and decide on your number. With that in hand, you can then decide on what building materials and techniques you need to get there.

I not only wish to record loud drums and guitars, but also would like to record quiet orchestral and choral pieces,

So far so good...

as well as some foley work.

:shock: :!: OK, we are back to brick then, no doubt about it. You might also need other extreme measures, such as a properly floated floor, or even a floated room. And all of a sudden your budget isn't looking so good any more... Foley work requires extreme isolation: you are recording very, very quite things and amplifying them enormously, so even tiny background noises become major issues. Your HVAC system, for example, now requires some major special attention: the flow speeds need to come down well under 100 fps, the AHU and compressor unit need much better isolation mounts, and the silencer boxes will have to be huge. You should probably also consider casting your pits in concrete, and you'll need to take special care with electrical and signal cabling too: Foley work sometimes requires water, and that doesn't mix with electricity too well...

Would something like MLV be a more appropriate solution for the walls and ceiling?

This one comes up quite frequently: I think I'll put it in the FAQ, or make a sticky about it some place. OK, it works like this: sound waves can be stopped by just four methods. That's it. The laws of physics are pretty clear on this. You can do one of four things to stop sound getting from "A" to "B". 1) You can put a barrier in between that is so massive (heavy) that the sound waves cannot move it. 2) You can put a barrier in between that is so rigid (stiff) that the sound waves cannot move it. 3) You can put a barrier in between that is so viscous (gooey) that the sound waves cannot move through it. 4) You can remove all possible paths between "A" and "B" that sound could follow, including air. Since #4 is out of the question unless you live in the space station, you have three left. Mass, rigidity and viscosity (or "damping"). Any one of those will do, but it turns out that the key is the first one: Mass. Lots of it. Huge amounts of it. Rigidity and damping also come in to the picture, but mass is king. Notice something here? There's no mention of price tag! The sound waves really don't give a hoot how much you pay for your mass: All they see is "mass", and that is what they react to. (Sound waves have very poor eyesight, and can't read prices... :) ) MLV is mass. Bricks are mass. Drywall is mass. Plywood is mass. OSB is mass. Concrete is mass. And all that sound waves care about is how may kilograms of mass they run into, NOT what that mass cost. So it just makes sense to use the least expensive material that has enough mass to do the job. MLV is not it. MLV is among the most expensive mass you can buy! Check the price, and kg for kg (or lb for lb), you'll find it costs several times what any of the others cost. Yes, MLV works, and yes it does have some legitimate uses in acoustic isolation, and yes I have used it myself when needed. But I would never use it when there are much less expensive materials available. For example, I have used MLV to silence the waste pipe from a toilet that ran through the ceiling of a home theater: Since MLV is flexible, it was the ideal material to wrap around pipe. Much easier than trying to box it in with drywall. But I would never use it as part of a wall sandwich: it is way too expensive for that. /RANT MODE = OFF/ ! :)

Should I simply triple-layer the drywall instead?

That's a really good option, yes, but not for Foley. It would work fine for a normal studio, even up to pretty high levels of isolation, but Foley is a special case.

Perhaps mass isn't such an issue with that much space?

Mass is always an issue, for acoustic isolation! The goal is to have the same surface density on the entire leaf, all around. So if you figure that you need, for example, 30 kg/m2 for your outer leaf, then that's what you need for your walls, doors, windows, HVAC silencers, electrical system, and everything else: If you have any part of the leaf that has less than 30 kg/m2, then you wasted an awful lot of money doing all the rest to the high level: an isolation wall is only as good as its weakest part.

The structure is build on a massive slab of concrete sitting directly on earth. I do not intend to float any flooring because I probably don't need it and would likely mess it up anyway.

:yahoo: :thu! Ahhhh! But wait a sec: Foley... You likely do need to float that floor, if you have traffic and aircraft. Even slight vibrations in the floor will get into your mics and end up as thunderous roaring in the recordings.

However, I would be interested in raising the floors (separately) in each room with simple 2x4

That's the same as floating a floor badly... :) Here too sound waves just don't care. You can explain to them that your floating floor isn't really meant to be a floating floor, and ask them very politely to ignore that fact that it isn't actually floating, but I don't think they'll listen... :) 8) Just run all your cabling inside the rooms, in a structured cabling system. Surface mounted rectangular ducts are great for this. Also, follow the general rule that electrical stuff runs at floor level, and signals level runs at the tops of the walls (sound, video, CAT6, etc.) That helps to keep hum and interference under control.

Just to reiterate, we will have engineers and acousticians on site periodically as this is simply too much money to not do things properly. But the more legwork I can get done on my own, the lower our expenses should be. Plus I enjoy learning.

for this size facility, and considering the investment, I would suggest that you should probably get a studio designer to do this for you, especially if you need it done this year. Realistically, it takes about six to nine months to learn all you need to know the basics of acoustics and studio design, HVAC, electrical, structure, etc. Then another three to six months to actually design a place like this. Then the actual building process can start. If you don't have a year or two to play with, then it might be worthwhile hiring a studio designer to do it all for you. If you have never done it before, you don't realize just how much goes into studio design, or how complex it can get. And there's one other factor here too: Foley. That's a whole different ball game. Designing a Foley sound stage is a big deal, due to the extreme isolation needed, and also the variable acoustics, and also the special requirements. Of course, if you have the time and the inclination, then by all means lean it and do it! I'd suggest two books to get you started: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. And also read John Sayers own work @ http://johnlsayers.com/Recmanual/index.htm But whichever way you decide to go, I'm sure looking forward to seeing this place go up! - Stuart -

Thanks! Happy to be here. ;)

That's a really nice sized space, especially the ceiling height. So is that 16' at the top plate? In other words, the bottom edge of the roof trusses is 16 feet above the floor? If so, that's excellent.

That's correct. It is currently a two story guest house. Our general contractor assures us that with proper bracing we can completely and safely remove that second level and have access to the roof. We will have a structural engineer confirm this before beginning demolition.

With nearly a thousand square feet of floor area to play with, you probably actually have space for more rooms, if you want them.

We did consider this. I initially drew up three different basic floor plans. The other two included an extra iso room but at the time we decided we really wanted a "wow" factor. We plan to install the new Avid S6 M40 and have large triple-pane telescoping sliding glass doors between the two rooms to really connect them - things that aren't in other local studios. We figured the large space would be the icing on the cake since no other studio in this area has that. We want to be a little different, but perhaps it wouldn't be a bad idea to rethink and offer one additional room. I'm sure we'd use it.

Also, what about other rooms you might need in the building? EG, bathroom, office, lobby, green room, storage, etc. Is there any need for those, or are they taken care of in another building?

There is one wall that we can build off of and it will be from the same wall as the two entry doors. The problem is that we can't go above 9' at the roof on that addition (for whatever reason) which makes it useless for extending the studio because the double-leaf wall will be part of the whole existing shell, floor to roof. We will be using this addition to add a 5' wide hallway along the length of the studio where there will be a bathroom and small utility closet as well as a warm and dry place for people to wait while the "recording" sign is lit. A separate building connected by a covered and paved walkway will house a lounge area, green room, and storage for musical instruments.

That would be excellent if you need really high levels of isolation, but that doesn't seem to be the case, so you can probably reduce that quite a bit, to gain space in the rooms. Normally a 10" thick wall (total thickness) will do the job of getting you good isolation. That would give you another 16" in each direction: worthwhile, for sure.

This is an interesting point. I sort-of arbitrarily chose a deeper pocket to lower any resonant frequencies, but really I wasn't sure if it was necessary. If bringing that down to 10"-12" wouldn't make an appreciable difference, I could certainly use the extra floor space. This is a place where perhaps taking loudness and frequency domain measurements would be of use.

The stone wall is a good idea, but live rooms don't necessarily need to be based on ratios. Control rooms do, for sure, but the purpose of a live room is to have a bit of "character" of its own. So ratios aren't as important for live rooms, and you don't need to sacrifice so much space behind the stone wall just for that.

I figured it couldn't hurt. ;) But again, if it means I get more floor space without an appreciable difference in sound quality, I'm all for it.

Here too you can reduce that quite a bit, unless you really do need very high levels of isolation. Taking that down to one foot can increase the size of either room, or both, or provide some extra space for adding one of those other rooms I mentioned.

This is another point I was curious about. I've felt from past experience in other studios that I could have used better isolation while tracking drums, however I don't know what construction methods were employed in those studios, and none of them had the monitoring horsepower that we plan to have (ATC SCM100ASL). Perhaps 10"-12" is in order here, too. That would be fantastic.

It would be good to measure the actual loudness of those trucks and planes with a sound level meter, to help you decide on how much isolation you need. If you could actually record them too, that would be great, so we can take a look at the spectrum of their noise, to help with the isolation concepts

Agreed. This is one of the next steps.

Labor is a big part of construction costs, so reducing that is a smart move, provided you have the skills and tools. There will likely still be some parts where you can't skimp, such as electrical work, structural calculations, HVAC installation, and a few others, but you sure can save a lot of money doing most of it yourself.

Absolutely! Luckily we have friends that are plumbers, journeyman electricians, general contractors, and so-forth. We will use up those wells all we can! However, to ensure things are done properly, we will be paying for services along the way for completely unbiased, professional assistance.

I reckon you can come in on-budget, but I wouldn't count on coming in much under it. There's this guy called "Murphy" who will see to that, no mater how well you plan...

That bastard...

There's a technique called "beefing up" that you can put to good use here, to add more mass to that outer leaf. Basically, you cut strips of drywall, OSB or plywood to fit in the studs bays of that wall, pushed up tight against the existing plywood, sealed with acoustic caulk, and held in place with cleats. That can substantially increase the mass (and therefore the isolation), as well as improving the seal.

Well this is good news! One of the original ideas was to place brick or concrete between the studs to place the mass there as well as add some structural stability, but in the end I just assumed that if the added mass wasn't continuous (due to the stud interference) that the acoustical benefits would be lost. If I may now switch directions for a moment: What if I were to go back to that original idea - add brick between the studs of the outer wall - insulate, then build the inner wall as a normal stud > double drywall system? That would certainly beef up the structural stability, but would it be a good method of acoustical control via mass? If so, I get the mass with the addition of gaining 3 1/2" of floor space since that mass is between existing studs.

You could also use fiberglass or mineral wool insulation in there, to save a few dimes. They key point for that insulation is the density: if you use fiberglass, then the density should be around 30 kg/m3, and if you use mineral wool then shoot for more like 50kg/m3. Those are optimum densities for damping inside MSM systems. Save the more expensive 703 for where it is really needed: treatment.

Good info. I like savings.

Skip the GG and drywall there: they aren't doing anything much for you. The density of brick is around 2000 kg/m3 (depending on type), so assuming you just do one thickness for your wall (3-1/2") the surface density would be about 180 kg/m2. The surface density of 5/8" drywall is around 11 kg/m2, so you'd need about sixteen layers of drywall to double the mass of the brick, and do something useful acoustically.... IF you need more mass than a single layer of bricks can provide, then just render the wall with a 1/4" or 1/2" coat of plaster: Much more mass for much less money, effort and space.

Good point. I'm not sure that I'd want brick as my surface for tonal reasons, but I haven't really thought too much about it. With proper treatment, it would probably work just fine. However now I'm back to considering the brick on the outer wall, so we'll come back to this...

From experience, you'll most likely have to change the plans many, many times as you move forwards! It's just the nature of the studio design process.

I figured as much. It's a fun process, though.

In between the studs is fine, but here the rule is "the more the merrier". The difference in total isolation of two identical MSM walls, where one is filled with insulation and the other has none at all, is as much as 16 dB. The more you put in, the better it gets. But your plan of 4" + 4" will likely already get you 10 dB or more, so depending on how much you need, you might of might need to fill the cavity.

And now we've already changed the outer and possibly inner walls, as well as the distance between them, so in the end it might just be completely filled anyway. This brings us back to the previous comment about using a mineral wool for the greater density, I was under the impression that if the well is filled completely and the insulation is touching both leafs, than that insulation should have as little rigidity and compression as possible to avoid shorting the system. I would think that a greater density would typically translate to a greater rigidity or compression. Perhaps I'm off the mark, or perhaps the higher density of the mineral wool is still too low to make such a difference. Just thinking out loud.

Absolutely yes and totally! Better buy shares in the caulk company now, as their stock is sure to rise once your rooms starts gulping down their products... In other words, sealing is critical to isolation. The objective is to make that outer-leaf wall totally air-tight. Hermetic. So yes, seal every tiny nook and cranny. Seal every miniscule crack. If it even looks like a crack, then seal it. Even if you are sure it is NOT a crack, then seal it anyway, just in case... Did I mention that sealing is important?

Sooo, is sealing important? or... ;)

Why not [have a brick ceiling]? ... It can be done.

Apparently so! Very cool photos. The concave ceiling wouldn't be my first option acoustically, although structurally it would be the most sound. I do like the look of the flat brick ceiling, and at my ceiling heights that could be something really special. Certainly no other studio in this area has that. It's a consideration, although it depends still on that outer wall idea.

That depends on the answer to the single most important question for deciding on how to build your place: "How much isolation do you need, in terms of decibels?"

Understood. I need to take measurements. Typically for this area, I could probably get away with a single outer wall, but those darn planes...

(Referring to foley) OK, we are back to brick then, no doubt about it. You might also need other extreme measures, such as a properly floated floor, or even a floated room. And all of a sudden your budget isn't looking so good any more... Foley work requires extreme isolation

This is true. I've done a small amount of foley work in the past and have run into noise issues for the quieter stuff. Perhaps given the current budget I won't pursue this field too deeply. I would still like to offer it, which means a well isolated room, but perhaps I won't actively advertise it.

You can do one of four things to stop sound getting from "A" to "B". 1) You can put a barrier in between that is so massive (heavy) that the sound waves cannot move it. 2) You can put a barrier in between that is so rigid (stiff) that the sound waves cannot move it. 3) You can put a barrier in between that is so viscous (gooey) that the sound waves cannot move through it. 4) You can remove all possible paths between "A" and "B" that sound could follow, including air.

This is understood.

MLV is among the most expensive mass you can buy! Check the price, and kg for kg (or lb for lb), you'll find it costs several times what any of the others cost. Yes, MLV works, and yes it does have some legitimate uses in acoustic isolation, and yes I have used it myself when needed. But I would never use it when there are much less expensive materials available.

This was not understood until now. Thanks for that! MLV is out.

[Triple layering drywall is] a really good option, yes, but not for Foley. It would work fine for a normal studio, even up to pretty high levels of isolation, but Foley is a special case.

It looks like foley is out, at least in a "dedicated" capacity. So, depending on where we land with the initial wall construction, potentially, triple drywall is a decent option. I assume this would be true for the ceiling as well?

Mass is always an issue, for acoustic isolation!

What I meant to ask was; given the amount of space from ceiling to roof and the amount of potential insulation in the cavity, was the same amount of mass as critical as it is with the walls, that will have much less space from inner to outer walls. Although, I think your answer is universal if I understand correctly. Add mass.

:thu! Ahhhh! But wait a sec: Foley... You likely do need to float that floor, if you have traffic and aircraft. Even slight vibrations in the floor will get into your mics and end up as thunderous roaring in the recordings.

The current room construction, which I was not part of, has this problem. Twice I've had to stop a recording due to the rumble of a passing airplane. Take off the headphones and you barely notice it, but through a pair of omni mics without a high-pass filter, it was definitely there! So, no foley, but still a potential issue. The mics were shock-mounted, so it was just excitement of the air probably caused by sympathetic wall resonance.

[Raising the floor with 2x4s is] the same as floating a floor badly... Here too sound waves just don't care. You can explain to them that your floating floor isn't really meant to be a floating floor, and ask them very politely to ignore that fact that it isn't actually floating, but I don't think they'll listen...

I was under the impression that as long as I kept a raised floor rigidly attached to the concrete slab (by direct contact with the 2x4s) that resonance wouldn't be an issue and it would be different from attempting to float a floor. Was this wrong?

Just run all your cabling inside the rooms, in a structured cabling system. Surface mounted rectangular ducts are great for this.

That's not a problem. I just like the idea of cleaning things up a bit and being able to open an access floor-board to the wiring channel. Not necessary though.

or this size facility, and considering the investment, I would suggest that you should probably get a studio designer to do this for you, especially if you need it done this year.

Sound advice. And we will definitely want this done within a year. There's the ROI we have to consider... :? I would still like to do the initial planning myself and then bring a collection of ideas and paperwork to a designer to help make these things a reality.

I'd suggest two books to get you started: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics)

I've actually owned this book for a long time and have read it often. I also picked up "Handbook for Sound Engineers" by Glen Ballou about 12 years ago and have about worn through the binding! I've just never paid too close attention to the studio design sections. I've been studying general acoustics for many years, but have never had the need to dive too deeply into studio design, and now I regret it! Thankfully we have forums like this to ease the blow. ;)

"Home Recording Studio: Build it Like the Pros", by Rod Gervais

I've seen this mentioned here a few times. I will definitely check it out. Thank you for taking the time to work with me on this, Stuart! You are a great help. :)

That was me. Apparently I logged out.

That was me. Apparently I logged out.

Yeah, that's been happening quote a bit the last few days, but it shouldn't. Guests should not be able to post without logging in. John and I are trying to figure it out, but neither of us changed any settings in the forum, so we aren't sure why that happened... So until we nail down the issue and fix it, please try to double-check before you post, that you really are logged in.

Our general contractor assures us that with proper bracing we can completely and safely remove that second level and have access to the roof. We will have a structural engineer confirm this before beginning demolition.

Your contractor speaks the truth! :) And your structural engineer will tell you how to do it right, but but hopefully it's just a matter of ensuring that the the walls have enough strength in sheer, maybe with some diagonal bracing on each wall face. There might also be a need for cross-bracing across the entire span of the shell, but hopefully not. If that is necessary, you'll just have to work with the structural guy to fit it inside the cavity between walls, if possible, so nothing from the outer-leaf penetrates the inner-leaf.

and have large triple-pane telescoping sliding glass doors between the two rooms

:shock: :!: :? Triple-pane is 3-leaf. Not good. It reduces your isolation, as compared to a two-leaf doors, for the same total mass and wall thickness. Either that, or I misunderstood your "triple pane", and you are actually talking about having two sliding panels and one fixed panel in your door, to get a wider opening? That would be OK, but you'd probably have to have those doors custom made: the seals where the two sliding panels come together would be a problem, in addition to the normal wall/floor seal issues. Sliding acoustic doors are great for that "wow" factor (take a look at some of John's designs!) but they are not cheap, and they do need to be done carefully: Remember the "seals" part? "Sliding" and "airtight seals" don't go together too well....

which makes it useless for extending the studio because the double-leaf wall will be part of the whole existing shell, floor to roof.

Ummmm... there seems to be a conceptual issue here: your exterior building shell is just the outer leaf of the two-leaf system: each individual room is the inner leaf. The shell cannot be two-leaves, since that would make each inner room into a 3-leaf system, thus reducing you low frequency isolation. Think of it like this: Your outer leaf is like an empty shoe box, an your individual rooms are like large matchboxes sitting inside that shoebox, but not touching it, and not touching each other. The shoebox is one-leaf, and each matchbox is one leaf. So now you have two leaves between any given room and the outside world, and you also have two leaves between any give room and its neighbors. This is the concept:

A separate building connected by a covered and paved walkway will house a lounge area, green room, and storage for musical instruments.

You probably already know this, but your storage are for instruments should keep the same environment (temperature and humidity) as the place they will be played: Some instruments are sensitive to temperature and humidity changes, just like some mics are.

This is an interesting point. I sort-of arbitrarily chose a deeper pocket to lower any resonant frequencies, but really I wasn't sure if it was necessary. If bringing that down to 10"-12" wouldn't make an appreciable difference, I could certainly use the extra floor space. This is a place where perhaps taking loudness and frequency domain measurements would be of use.

Right! You can adjust your isolation (MSM resonant frequency) in two basic ways: change the mass on each leaf, or change the depth of the cavity between them. so if you want a smaller cavity to get more floor area, you can increase the mass to compensate for that. In general, you shouldn't go much below 4" for the depth of the cavity, as you start to get into "diminishing returns" there: at that point making the leaves thick enough to compensate for the smaller cavity means that you end up using more space for the extra mass than you gain from the cavity depth. Unless you use more exotic (and expensive) materials for your mass, such as steel plate, lead sheeting, or suchlike. If you really want to get into the calculations, then the equation for the resonant frequency of a 2-leaf MSM wall is: Have fun! :) :wink:

This is another point I was curious about. I've felt from past experience in other studios that I could have used better isolation while tracking drums,

Right! Drums are teh hardest of all instruments to isolate, since they are LOUD (115 dB is typical) and a lot of that energy is in the low end of the spectrum, which is the most complicated to isolate. Killing drums needs more dense walls and larger air gaps, and things like Green Glue can also help: that gives you the extra bit that you need in the low end, and your budget can take that, I reckon. For your drum booth (if you so a separate one), I would consider more dense wall and ceiling materials, such as fibercement instead of drywall: It's about twice as dense, meaning in the same thickness panel you get twice the mass. For example, consider a wall that has an initial layer of 3/4" MDF on the studs, then two layers of 3/8" or 1/2" fibercement board with Green Glue between them, over an 8" gap filled with mineral wool. That can give you pretty high levels of isolation, approaching 70 dB, with luck, and going down to well below the fundamental frequencies of the kick and floor tom. That would be a good option. But then you also need to do the HVAC silencers in the drum booth to the same level of isolation, and also the electrical and signal wall penetrations. And the door seals. (Did I before mention that seals are important? :horse: :roll: )

the monitoring horsepower that we plan to have (ATC SCM100ASL)

Awesome! :thu: You know, if you REALLY wanted to have those things causing some major "wow" factor in your place, you could soffit mount them... :) The are front ported, so there's no problem there. Your room would sound beyond awesome if you did that... No SBIR, no edge diffraction, not comb filtering, no reflections off the front wall, baffle-step power response corrected.... I'd seriously suggest that you give it some thought.

Well this is good news! One of the original ideas was to place brick or concrete between the studs to place the mass there as well as add some structural stability, but in the end I just assumed that if the added mass wasn't continuous (due to the stud interference) that the acoustical benefits would be lost.

Bricks in the stud bays would be overkill, probably, and you are right about the studs being an issue. The density of typical studs is only about a third to a quarter of the density of brick, so you'd be losing a lot right there. MDF and drywall, on the other hand, are more or less the same density, so continuity of the same surface density around the entire wall is not an issue. Adding 2 or 3 layers of "beef" inside your stud bays can get you some substantial mass on that outer leaf.

What if I were to go back to that original idea - add brick between the studs of the outer wall

See above, plus how would you set the bottom course of bricks? It would be resting on the sole plate... :shock:

Good point. I'm not sure that I'd want brick as my surface for tonal reasons,

Well, you'll need more or less the same treatment to get the room acoustics under control, regardless of the building materials. Walls made from brick or drywall won't be a whole lot different in that aspect: Treatment is mostly related to room dimensions and total isolation: surface materials are less relevant. One option you might want to look at if you go with stud framing for your inner-leaf walls, is "inside-out" construction. Basically, you build the wall "backwards", in the sense that the drywall faces the cavity and the studs face the room. So you end up with the entire group of stud bays for basic treatment. John invented this system many years ago, and has used it a lot, as have many forum members. It can help a huge amount.

I was under the impression that if the well is filled completely and the insulation is touching both leafs, than that insulation should have as little rigidity and compression as possible to avoid shorting the system.

Right. That's why you only "fill" the wall: you don't "overfill" it. You don't force the insulation in so hard that it creates a flanking path: you just lay it in so that it is just reaching both leaves.

I would think that a greater density would typically translate to a greater rigidity or compression.

That's one of the reasons why you don't use high density insulation! The other reason is optimum damping: 30 kg/m3 for fiberglass an 50 kg/m3 for mineral wool are the peak points where the damping is at maximum efficiency, so you get the best "bang for the buck" at those points. If you use some other type of insulation, then you'd have to use a different density. Actually, it isn't really the density that matters: it is a parameter called "gas flow resistivity", which is sort of like how much the insulation resits the movement of air. But since most insulation manufacturers don't bother measuring or publishing that information for their products, it is hard to find. Fortunately, there's a reasonably good relationship between the density and the gas flow resistivity of each type of insulation: it's not linear, and not perfect, but close enough for our purposes. So those are the densities where the gas flow resistivity is most suitable for MSM damping. Filling with insulation also changes the way the air responds to pressure waves, from isothermal to adiabatic, and extends the average path length that a sound wave "sees" as it moves through the cavity, thus making it "seem" bigger than it is. Good stuff all around!

The concave ceiling wouldn't be my first option acoustically,

Right! But you could hang hard-backed clouds below it, or other acoustic devices, to compensate for the focusing effect, and you could build it as a catenary curve (poly-cylindrical) instead of constant radius... :) And it looks pretty cool, if you want "wow" factor! Of course, that would be for the live room: the control room would be much better off with a flat ceiling. But imagine that in your live room...

So, depending on where we land with the initial wall construction, potentially, triple drywall is a decent option. I assume this would be true for the ceiling as well?

Right. However, there's a potential issue with your roof, depending on how it is built: you might need a 3-leaf system up there: in some cases it is unavoidable.

I was under the impression that as long as I kept a raised floor rigidly attached to the concrete slab (by direct contact with the 2x4s) that resonance wouldn't be an issue and it would be different from attempting to float a floor. Was this wrong?

Let me put it this way: If you bolt down your kick drum rigidly to the floor, will it sound any less resonant? :) Any time you have a membrane (eg, plywood subfloor) stretched out over an air cavity, then you have a drum. It is a resonant system, for two reasons. One is the membrane, the other is the cavity. Just like a kick drum, there are two "sounds" going on. One is the resonance of the membrane itself (the sound of the beater hitting the drum head), and the other is the actual cavity sound (the reverberance of the air inside the drum shell). so a raised floor is basically just a kick drum, and it sounds like one too. Sure, you can add mass and rigidity to the floor "membrane" but the amount of mass and rigidity you need to push the resonance down below the bottom end of the spectrum, puts you in the realm of a thick reinforced concrete slab. That's why you see studio designers and acousticians giggle a bit at the attempts you often see on YouTube to "float" floors and rooms with 2x4s and plywood. The mass and rigidity just aren't there. I'm not sure if you saw this thread? viewtopic.php?f=2&t=8173 Here's some more technical info on the pitfalls of floating things in studios: http://archive.nrc-cnrc.gc.ca/obj/irc/d ... /ir802.pdf

That's not a problem. I just like the idea of cleaning things up a bit and being able to open an access floor-board to the wiring channel.

Surface-mount structured systems do allow you to do that. They usually have clip-on plastic covers that you can remove to get access to your cabling. Legrand is the manufacturer I normally use, but there are others.

I've been studying general acoustics for many years, but have never had the need to dive too deeply into studio design, and now I regret it! Thankfully we have forums like this to ease the blow.

That's what we're here for! :thu: - Stuart -

Guests should not be able to post without logging in.

It asks me to place the names in the correct box like it did when I signed up, if that helps. Since it was my first "reply" I didn't think much of it.

...hopefully it's just a matter of ensuring that the walls have enough strength in sheer, maybe with some diagonal bracing on each wall face. There might also be a need for cross-bracing across the entire span of the shell, but hopefully not.

Given enough space, We might just be able to add steel beams between the partitions separating the rooms, since they are individually housed. We'll find out soon enough.

Triple-pane is 3-leaf. Not good. It reduces your isolation, as compared to a two-leaf doors, for the same total mass and wall thickness. Either that, or I misunderstood your "triple pane", and you are actually talking about having two sliding panels and one fixed panel in your door, to get a wider opening? That would be OK, but you'd probably have to have those doors custom made:

The later is what I meant. ;) I was looking specifically at these sliding glass doors. I'm sure I used the wrong terminology.

Ummmm... there seems to be a conceptual issue here: your exterior building shell is just the outer leaf of the two-leaf system: each individual room is the inner leaf. The shell cannot be two-leaves, since that would make each inner room into a 3-leaf system, thus reducing you low frequency isolation.

No issue, just me using improper phrasing. Again. We plan to build in from the shell before adding the hallway. The shell would be the first leaf. The external hallway would I suppose be considered a third leaf if done this way, though I didn't think it an issue being at least a 5-foot wide space. Is this the wrong way of thinking? The issue is; since we can't tear down the existing structure, that wall along where the addition is to be built must remain. I can only poke a hole for a second door. (I don't get it either. Zoning stuff.) I don't see any way around this aside from making that hallway its own structure. I will draw up a new floor plan today with the add-on to help visualize. Maybe you'll come up with a better solution.

You probably already know this, but your storage are for instruments should keep the same environment (temperature and humidity) as the place they will be played: Some instruments are sensitive to temperature and humidity changes, just like some mics are.

As a drummer and guitarist, I'm all too aware of this. We plan to own two drum sets (an old bop kit and a yamaha recording custom), multiple guitars/basses and amps, a b/c3 with leslie. and various percussion. Plus whatever we can get our hands on, really. We simply don't want to take floor space with all of this gear. In an earlier plan that had a dedicated iso room with shorter ceilings, I had the idea of storing the stuff on the "roof" of that iso booth, which could look pretty stunning as well with some nice lighting. But then I switched to an open plan. The lounge area would be climate controlled to match the studio, and the walk between the two is less than 100'. Plus it might be kind of neat to allow the musicians to grab a guitar or something while playing pool. Microphones will be stored in the studio. I might be exploring the iso-rooms again, in which case it might be cool to store the instruments above again. Perhaps with a sliding library-style ladder. I quite like that, actually...

If you really want to get into the calculations, then the equation for the resonant frequency of a 2-leaf MSM wall is: ... Have fun!

I will! Thanks for that. I'm sure I'll be using this.

For your drum booth (if you so a separate one), I would consider more dense wall and ceiling materials, such as fibercement instead of drywall: It's about twice as dense, meaning in the same thickness panel you get twice the mass. For example, consider a wall that has an initial layer of 3/4" MDF on the studs, then two layers of 3/8" or 1/2" fibercement board with Green Glue between them, over an 8" gap filled with mineral wool.

I forgot about this stuff! At a cost of just over double drywall, it would certainly be within my budget to use this as an initial layer throughout the entire live and control rooms, assuming I forgo brick. I know it doesn't have the density of brick, but it is much more thin, and considerably cheaper. Could this treatment be used for the ceiling as well?

But then you also need to do the HVAC silencers in the drum booth to the same level of isolation, and also the electrical and signal wall penetrations. And the door seals. (Did I before mention that seals are important?

I think I heard that somewhere... The HVAC and electrical are two areas where a professional on site is a necessity. I feel like this is where I would waste most of my time in research. At a certain point, you just have to budget things in.

Awesome! You know, if you REALLY wanted to have those things causing some major "wow" factor in your place, you could soffit mount them...

I've used the ATCs once before and I just can't look back. 8) I've considered the soffit mount approach but didn't think too much on it since I'm not confident in my ability to do it right. However, I think you are correct with the "wow" factor and really, that's what we want. I will learn, or I will hire. Since your first reply, I've worked on some new room dimensions both with and without iso rooms. The depth of the control room is sitting at a comfortable 22', which leaves plenty of room for a soffit. The width is 12' and the height goes all the way to 16'. These are equally good dimension ratios and I can hang clouds to "lower" the ceiling where it counts.

I'd seriously suggest that you give it some thought.

Done! I will explore this, most definitely. ;)

Bricks in the stud bays would be overkill, probably, and you are right about the studs being an issue. The density of typical studs is only about a third to a quarter of the density of brick, so you'd be losing a lot right there. MDF and drywall, on the other hand, are more or less the same density, so continuity of the same surface density around the entire wall is not an issue. Adding 2 or 3 layers of "beef" inside your stud bays can get you some substantial mass on that outer leaf.

Good note, and more cost effective.

Well, you'll need more or less the same treatment to get the room acoustics under control, regardless of the building materials. Walls made from brick or drywall won't be a whole lot different in that aspect: Treatment is mostly related to room dimensions and total isolation: surface materials are less relevant.

I like the tone and look of a nice wood room, especially in the higher frequencies, but there is something appealing to a massive brick structure. And with proper treatment, I suppose the tonal differences wouldn't be an issue. This is an area where I might come up with two designs - one fiber cement and drywall - the other brick. At that point I can see what a professional studio designer has in mind. I might be leaning toward the fiber cement and drywall approach only for cost and ease of construction.

One option you might want to look at if you go with stud framing for your inner-leaf walls, is "inside-out" construction. Basically, you build the wall "backwards", in the sense that the drywall faces the cavity and the studs face the room. So you end up with the entire group of stud bays for basic treatment. John invented this system many years ago, and has used it a lot, as have many forum members. It can help a huge amount.

This is an interesting approach. I'll look into that.

That's one of the reasons why you don't use high density insulation! The other reason is optimum damping: 30 kg/m3 for fiberglass an 50 kg/m3 for mineral wool are the peak points where the damping is at maximum efficiency, so you get the best "bang for the buck" at those points. If you use some other type of insulation, then you'd have to use a different density.

Great insight! Mineral wool might be the way to go, then.

Right! But you could hang hard-backed clouds below it, or other acoustic devices, to compensate for the focusing effect, and you could build it as a catenary curve (poly-cylindrical) instead of constant radius... And it looks pretty cool, if you want "wow" factor! Of course, that would be for the live room: the control room would be much better off with a flat ceiling. But imagine that in your live room...

That would look fantastic, especially at 16'!

...there's a potential issue with your roof, depending on how it is built: you might need a 3-leaf system up there: in some cases it is unavoidable.

Could you elaborate on this? The A-frame, directly connected to the outer shell walls, would be the first leaf, then would be insulation (mixed in with a myriad of structural beams and duct/electrical), then would be the ceilings of each room as the second leaf. Am I missing a step?

Let me put it this way: If you bolt down your kick drum rigidly to the floor, will it sound any less resonant? Any time you have a membrane (eg, plywood subfloor) stretched out over an air cavity, then you have a drum. It is a resonant system...

Understood, and rather obvious now. Sometimes someone else just needs to say it before you can whack yourself on the forehead and say "duh!" Hardwood directly on concrete it is. ;)

Surface-mount structured systems do allow you to do that. They usually have clip-on plastic covers that you can remove to get access to your cabling. Legrand is the manufacturer I normally use, but there are others.

I will check them out. Thanks again, Stuart!

Taking into account a number of Stuart's points, I've made some adjustments (as I figured I would). We'll start with the images: The most obvious change is the shifting of the main wall and additions of two rooms, plus a rough drawing of where the hallway addition will be. The box in the control room is just a personal reference of where 38% into the room lengthwise sits. The current inside dimensions are (roughly) as follows: Control Room - 22' L x 12' W x 16' H Live Room (asymmetrical) - 22' L x 19.5' (long end) 15.5' (short end) W x 16' H Iso/Drum Booth 1 (asymmetrical) - (roughly) 11.5' L x 9' W x 13' H Iso Booth 2 - 9' L x 5' W x 13' H I gained a bit of floor space by making the depth of the outside walls 1' instead of 1.5'. I also made all internal isolating walls 1' to match. Moving the control room wall allowed me to gain space in the big room without sacrificing acoustics in the control room. The ceiling had to go up to compensate, but there will be clouds at appropriate heights to manage the rooms mid and high frequencies while allowing the LF to make use of the larger dimensions. The large iso room can comfortably fit a drum set or percussionist or can be used for any other needs if the drums are in the live room. The smaller iso room is still large enough to comfortably fit two people if necessary. On the closeup you can see that in addition to cutting the space down to 1', I've added mass to the outer wall with two cut-to-fit pieces of drywall (caulked and with green glue) in between the studs. On the inner leaf is a sheet of 1/2" concrete board with two layers of 5/8" drywall (all with green glue). Between the two leaves is roughly 8" of insulation (fiberglass or mineral wool). The addition on the outside will be a long connected hallway with a bathroom, which is roughly 5.5' wide. It is included to discuss ways of connecting it to the main building. As I mentioned earlier, since I cannot completely demolish any outer walls, I have to make the main facility outer wall a complete leaf. There is a decent possibility of extending that addition to beyond 6' if that will help to somewhat diminish the triple-leaf effect. It would also leave a bit more room for storage. However, due to cost, if making the opening larger has little to no effect, perhaps I need to think of other options. Thanks again!

I also intend to look into soffit mounting for the control room, but I'm not quite there yet.

I was looking specifically at these sliding glass doors.

Cool! I didn't know anybody made them as standard items. You live and you learn. I'm going to take a closer look at their technical data, to see how the really perform: I always get a bit concerned when I see isolation numbers for studios quoted as STC ratings... :)

The external hallway would I suppose be considered a third leaf if done this way, though I didn't think it an issue being at least a 5-foot wide space. Is this the wrong way of thinking?

No, that's fine. You got it right. It is a third leaf, yes, but with a 5-foot air gap the MSM resonance is so low as to not be an issue. Below 10 Hz, for sure.

The issue is; since we can't tear down the existing structure, that wall along where the addition is to be built must remain. I can only poke a hole for a second door. (I don't get it either. Zoning stuff.) I don't see any way around this aside from making that hallway its own structure.

Don't you just love the way regulations are so logical, consistent, clear, and well thought out? :shock: :!: :lol: ( /SARCASM MODE = OFF/ )

At a cost of just over double drywall, it would certainly be within my budget to use this as an initial layer throughout the entire live and control rooms, assuming I forgo brick. I know it doesn't have the density of brick, but it is much more thin, and considerably cheaper.

If you can get a 1/2" panel of fiber-cement for about twice the price of 1/2" drywall, then you are doing fine! You are paying about the same per kilogram (or per pound) of mass, which is good value for money. Where I live, it's a bit more expensive, but still an excellent option. But I would use OSB, MDF, or plywood as the first layer, then put the fiber-cement board as the second layer: That gives you the additional advantage of 100% nailing surface around the entire room... very useful when it comes time to hang acoustic treatment on the walls: you don't need to go stud-hunting!

Could this treatment be used for the ceiling as well?

Yup, it sure can.

The HVAC and electrical are two areas where a professional on site is a necessity. I feel like this is where I would waste most of my time in research. At a certain point, you just have to budget things in.

Right, but do make sure you get an HVAC guy with studio experience! Doing HVAC for studios is rather different than doing it for a house, office, school, shop, etc. If he has never done studios with high isolation before, he won't get the need for duct liner on the inside of all ducts, massive silencer boxes, decoupling sleeves on all connections to equipment, hugely over-sized ducts and registers, and all the other things that are absolute necessity for a studio.

I've considered the soffit mount approach but didn't think too much on it since I'm not confident in my ability to do it right. However, I think you are correct with the "wow" factor and really, that's what we want. I will learn, or I will hire.

Did you notice that the manufacturer's own website shows pictures of those very same speakers, soffit mounted in glass? Just sayin' .... :)

Since your first reply, I've worked on some new room dimensions both with and without iso rooms. The depth of the control room is sitting at a comfortable 22', which leaves plenty of room for a soffit. The width is 12' and the height goes all the way to 16'

Your ratio would be 1 : 1.33 : 1.83, which is within spitting distance of Louden 2, ( 1 : 1.3 : 1.9 ): Nice! Room volume is about 4200 cubic feet: Also nice! Floor area around 1600 ft2, and you have modal support all the way down to 25 Hz. I would still tweak those a bit, to center the axial modes more on musical notes, but overall that looks like a really nice size. The soffits will bring the average length down a bit, and slightly on the width too. And since you are going with soffits, I'd also suggest going the whole distance, and doing a full RFZ design. Wow factor isn't just visual: aural is also rather important for a studio, and a well done RFZ designed control room is going to raise that Wow factor a few notches on both fronts. How many RFZ rooms are there in your area? How many studios have soffit mounted speakers? :)

Could you elaborate on this? The A-frame, directly connected to the outer shell walls, would be the first leaf, then would be insulation (mixed in with a myriad of structural beams and duct/electrical), then would be the ceilings of each room as the second leaf. Am I missing a step?

Ventilation: your roof deck very likely needs to be ventilated from below (depending on what type of deck it is). That implies air vents under the eaves to bring air in, and either a ridge vent or gable end vents to allow it out again. Building codes normally require roof ventilation, and if they don't it's just a good idea to do that. If there is no ventilation up there, the attic space can get extremely hot in summer, and very cold in winter, which can do damage over time. You don't want to be replacing your roof deck every few years, I'm sure! Depending on where you live, there's also the potential for condensation, mold, ice, and other unpleasant things happening to the roof deck and the attic space, if the deck isn't ventilated. So if you have to ventilate, then obviously the roof deck cannot be sealed to the walls, meaning that it cannot be your outer leaf. In that case the best solution is to seal off the entire attic space from your studio by putting a "middle leaf" across the top of your outer-leaf walls, leaving the roof all to its self, to be ventilated any way it needs to be. There is the potential for typical third leaf issues with that: Even though the roof can't be your outer-leaf (because of the vents), it can still act as a leaf, since it is just a layer of mass over an air gap. So it's best to assume it will be a 3rd leaf (remember Murphy?). The antidote is to make the middle leaf more massive and use a bigger air gap under it, as compared to the way it would have been if there were just two leaves. Optimal is to have the middle leaf with as much mass as the other two combined, and the air gap about 50% bigger than it would have been otherwise. That pretty much puts things back where they were, in in terms of MSM resonant frequency and isolation. Not sure if that made any sense at all! It's 1 AM here, and I need to get some shut-eye!

Understood, and rather obvious now. Sometimes someone else just needs to say it before you can whack yourself on the forehead and say "duh!" Hardwood directly on concrete it is.

:) :thu: and now that I threw you that curve ball, I'll totally confuse you by throwing you a reverse-curve ball (whatever that is!) and saying that it is possible to raise parts of the floor, if done right. For example, a drum riser, or the raised area for your client couch at the rear of the CR... :) They can be done, but do need careful design...

I will check them out.

They make great products, but their web site is a disaster for finding what you want, even when you know exactly what it is! So let me give you a hand: http://www.legrand.com/EN/cable-management_12722.html Scroll down to the bottom, and click on the "Complete perimeter solutions" video. It shows you how the whole system fits together. Now, if you can then figure out how to find the actual individual products that make up the solution, on their web site, then you have much better blind-navigation skills than I do! :) I just go to the the local hardware store, and look on the shelf: it's much easier... - Stuart -

Just took a better look at those doors: they claim 40 dB isolation at 80 Hz for a pair of 5/8 + 5/8 doors with a 10" gap. Pretty impressive! Even allowing for marketing hype and knocking off a few points, that's still very respectable. Thanks for the link. Any idea on pricing for those things? Cheap they ain't, I'm pretty sure... - Stuart -

Any idea on pricing for those things? Cheap they ain't, I'm pretty sure...

No clue. I will contact them when it comes time to put together a rudimentary materials cost spreadsheet. When I do, I'll let you know.

I would use OSB, MDF, or plywood as the first layer, then put the fiber-cement board as the second layer: That gives you the additional advantage of 100% nailing surface around the entire room.

Good idea. Is this a better option than resilient channel on the walls and ceiling?

Right, but do make sure you get an HVAC guy with studio experience!

Absolutely!

Did you notice that the manufacturer's own website shows pictures of those very same speakers, soffit mounted in glass? Just sayin' ....

I saw that. Seems like that might introduce a few new problems, but at least they are confident in soffit mounting their own speakers.

Your ratio would be 1 : 1.33 : 1.83, which is within spitting distance of Louden 2, ( 1 : 1.3 : 1.9 ): Nice! Room volume is about 4200 cubic feet: Also nice! Floor area around 1600 ft2, and you have modal support all the way down to 25 Hz. I would still tweak those a bit, to center the axial modes more on musical notes, but overall that looks like a really nice size. The soffits will bring the average length down a bit, and slightly on the width too.

I've been making great use of Bob Golds room mode calculator. Very handy. In case you didn't see, I had another post just before your reply which shows a newer floor plan with dimensions. I guess we can add to those a layer of plywood. I'm still unsure about the soffits. I keep going back and forth. I really like the idea of being able to move the speakers, but then again, I really like the idea of NOT being able to move the speakers... If that makes sense... I'm probably just a bit overwhelmed by the pressure to get that bit right.

Ventilation: your roof deck very likely needs to be ventilated from below (depending on what type of deck it is). That implies air vents under the eaves to bring air in, and either a ridge vent or gable end vents to allow it out again. Building codes normally require roof ventilation, and if they don't it's just a good idea to do that. If there is no ventilation up there, the attic space can get extremely hot in summer, and very cold in winter, which can do damage over time.

This makes sense. I live in a temperate zone that isn't too humid, rarely gets above 80 in the summer or below 30 in the winter. I'm sure I'll have to discuss this with a local professional, but while we're here; would it not be sufficient to simply stuff the roof with insulation? It's a lot - 4' at the apex of a 41' x 24' roof. But I like options when available.

Not sure if that made any sense at all! It's 1 AM here, and I need to get some shut-eye!

You seem to be doing just fine. ;)

I'll totally confuse you by throwing you a reverse-curve ball

I think for now I'm going to plan on no floating floors. When I initially had the open floor plan I liked the idea of removing the sofa and having more flat ground to use if needed. Although I see a step up in many facilities, I don't see much practical purpose here. I've heard that one purpose is to align the sat ears with the HF, but I don't buy that. I was on the team that developed a distributed mode loudspeaker (Tectonic Audio Labs) and got to understand dispersion characteristics pretty intimately. At ~20' with a 10 degree vertical dispersion, that back wall should be pretty well covered. Plus my doors will be on that back wall. Somehow... :P They do look nice, though...

They make great products, but their web site is a disaster for finding what you want, even when you know exactly what it is! So let me give you a hand:

Very elegant looking! Although that website... Can you count the links? Thanks again!

Good idea. Is this a better option than resilient channel on the walls and ceiling?

You only need RC if your leaves are on the same set of studs. Ie, not decoupled. RC decouples them. But if you have your leaves totally separate from each other already (fully decoupled), then you don't need RC. Decoupling twice gives no additional benefit, except to improve the manufacturer's cash flow!

Seems like that might introduce a few new problems, but at least they are confident in soffit mounting their own speakers.

Right on both counts! You might not have noticed, but I'm a big fan of soffit mounting. It makes so much sense, in so many ways. But I don't think I'd like to try doing it in glass, as in that photo...

I've been making great use of Bob Golds room mode calculator. Very handy.

Yup. It's my favorite. AndyMel has a pretty cool one, too. It even auralizes your modes for you... http://amroc.andymel.eu/ , and you can view axials, tangentials and obliques in any combination.

I'm still unsure about the soffits. I keep going back and forth. I really like the idea of being able to move the speakers, but then again, I really like the idea of NOT being able to move the speakers... If that makes sense...

How about eating your cake and having it too, so to speak? Do both! :shock: :!: Soffit mount one set, and have another set on stands. If the room is reasonably large, then you should be able to do that, with careful design.

I'm probably just a bit overwhelmed by the pressure to get that bit right.

That's what we're here for! To watch you sweat, that is... :) Naah, I mean that we are here to help you get it right.

I've heard that one purpose is to align the sat ears with the HF, but I don't buy that. I was on the team that developed a distributed mode loudspeaker (Tectonic Audio Labs) and got to understand dispersion characteristics pretty intimately. At ~20' with a 10 degree vertical dispersion, that back wall should be pretty well covered.

Right! I'm totally with you there. The real reasons I've heard for having a raise client couch are mainly marketing, believe it or not! Not acoustic at all. Apparently, it gives the client a sense of being important, and a sense of control, and other such things. And if you think about it, since most client couches in small studios are either up against or very close to the rear wall, they aren't exactly in an acoustic sweet spot anyway.... Even worse, you often see studios with large numeric-sequence diffusers on the rear wall, just inches from the client's head :shock: :lol: So it's pretty clear that the couch is not there to give the client a good listening experience, in most cases. That can only happen for pretty large size control rooms, where there is space to actually get the couch in a good acoustic location. - Stuart -

Great Thread so far! I've been searching for info on studio quality sliding glass doors for my studio. I found the site you found, Soundproof Windows.com. I read their spec sheets and a few reviews and decided to email Jack for a quote... For a pair of 5/8" thick glass sliding doors from them, one for the inner and outer leaf of my drum booth, I was quoted $5000.00!! :shock: before shipping! :cen: However, he did boast to say that you could have a drum set banging away on one side of the opening and track vocals on the other side with no crosstalk. Pretty bold statement. As much as I would like to spend $5k, its just not in the budget. I ordered the exterior windows in by building from Pella and decided to contact the rep I was dealing with to pick his brain on their sliding glass doors to see if a custom built door from them was a possibility. I asked if they could build a set with solid laminated glass as opposed to the 3-pane system they typically use. He told me it was possible so I sent him some specs and am waiting to hear back. But honestly, I just dont trust the door frames that would house the glass to be dense enough to equal the mass of the surrounding walls and the glass for the door. Plus, on all of their doors I've seen the track system is always pretty whimpy and doesn't seem like it would do a great job of sealing up for sound. I've been trying to find info on how to build some DIY sliding glass doors but have had no luck. Luckily a friend of mine is a glass wholesaler so I can get all types and thicknesses of glass for next to nothing in cost. But building a track system for the doors that would give a great seal while supporting the weight of at least a 5/8" thick piece of glass in a wooden beefed up frame similar to the "super door" method. Im totally stumped! I may just go back to my original plan of a door and window as opposed to sliding glass but I'm not gonna give up without exhausting the possibilities. Would either of you have any input on the subject or be willing to direct me to a thread that is more on the topic of sliding glass doors? Cheers, Jason

Would either of you have any input on the subject or be willing to direct me to a thread that is more on the topic of sliding glass doors?

I think you've pretty much found everything you need to know: Acoustic sliders are great, look cool, work well, provide excellent sight lines, but cost a fortune. And the ones that don't cost a fortune are not good for isolation. That pretty much covers it, unfortunately. The cheap ones aren't good, and the good ones aren't cheap.... - Stuart -