Hi there "rabbleroust", and Welcome!
I think it's reasonable to build a great spot without spending bazillions of dollars
Very true! If you design carefully, and work really carefully, and scrimp and save, you can probably do it for about half a bazillion.
It would be tight, but do-able...
Jokes aside, there's a lot of truth in that: good design and careful construction can save you money. Mostly the "good design" part. If the design is not complete, detailed, accurate, and tripe-checked for every last aspect before you start, then construction will cost you more than it would have otherwise...
We have a lot of inherent challenges that come with the shape and construction of the existing building
I'm sure you already know this, but curved shapes are the worst! In order of "terrible to acceptable", the very worst possible shape is a sphere or spherical dome, followed closely by a cylinder or cylindrical dome...
As luck would have it, I'm in the middle of a design for a customer who has a very, very similarly shaped room, Quite a bit smaller than yours, but the same basic shape. So I can tell you from first-experience that you are in for a "fun" ride with designing your inner-leaf rooms to fit in there!
I would like to be able to track / rehearse at all hours, if it's possible. My usual volume is low, but when I track drums or guitars things can get loud of course.
First order of business: put a number on that. How loud will your loudest tracking session be? How loud do you mix/master? You need to get out your hand-held sound level meter, and measure real-world numbers, in decibels (dBC, Slow). You also need to measure / find out how quiet you need to be...
The auto body shop is quiet,
That's unusual! Most body shops I've been to have things like pneumatic tools, compressors, hammers, presses, clumsy mechanics dropping heavy metallic things.... not to mention engines starting, running and stopping all the time as cars are moved around. A quiet body shop would be a strange animal....
I can't find my SPL meter right now,
A new search is in order! Without that, all your design is just guesswork. You might be way overdoing the design, wasting money and materials, or you might be "under-doing" it, and thus will end up with a place that does not meet expectations... and subjects you to frequent visits from the cops, and perhaps even legal issues.
I know that this sort of rounded shape is not desirable acoustically,
Yup!
but the size of the room should allow me to build another leaf inside it that has some better geometry.
True!
Even now the room, untreated, sounds smooth and gorgeous - maybe the room size and shape of the metal pieces are smoothing out the sound nicely?
It's possible, but I'd do some careful testing at various places in there. You might find that listening / tracking down the long axis, where the big pipes are creating useful diffusion, is one thing, while listening tracking in the sideways axis is much more problematic, where you get reflections from the curved ceiling.
The other issue is isolation: How much are you getting from that shell right now? Is ii sufficient for your needs, and to meet legal requirements? If so, it might be feasible to just treat the curved surfaces in between the pipes. If not, then you'll need to build the actual live room inside that shell, as a separate leaf.
the roof is a spray-foam that's approx 6'-8' deep.
Any more info on that foam? Specifically, is it closed-cell or open-cell? And what type of foam?
The floor at the moment is dirt, and I'm planning on pouring an isolated slab.
Smart move. From all you say, you are aiming for high levels of isolation.
At the moment, there is no direct access to the back structure from the large hall - I'm planning on adding doors and windows between the two so that access and line of sight is good when tracking in both spaces.
What we want to accomplish is two-phase.
Since you've been reading the forum for a while, you've probably seen me give this advice before, but it bears repeating: Even if you are going to build in stages, first design EVERYTHING before you build any of it. If you design and build one part now without any regard for the rest, you will very likely find that when the time comes to do the second part, you won't be able to! Or you will, but only with large compromises, or only after taking apart some of what you already built.
When I'm working on a multi-room facility design, I frequently change things around many times, putting rooms, doors, windows, HVAC components, etc. in different places, with different sizes, orientations, etc., and often I suddenly find a layout that makes a lot more sense than what I had originally, and I realize that the original would have been less-than-optimal in some aspect. It's only once I have all rooms in place that I can see how the studio will work as a whole. And only then can I start optimizing each part of it. The studio has to work as a complete facility that runs smoothly, not just a bunch of rooms.
So even if you don't plan to build some parts yet (the "second phase"), they still need to be designed fully, in complete detail, along with the "first phase".
Ideally, the room will have both both good acoustics for mixing and good/fun acoustics for tracking.
This is another discussion you might have seen me have several times!
The acoustic response that you need for a control room is laid out clearly in documents such as ITU BS.1116-2 and EBU Tech-3276, among others. When you have a room that meets those specs, this is what the acoustic response looks like
http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 . That's a great room for mixing and mastering: it meets or beats all the specs. But I would not want to record many types of instruments in there. The acoustics just aren't meant for that. The perfect, low decay times and dead flat response that you need for a good control room are too dry and "lifeless" for most instruments. Tracking vocals and maybe acoustic guitar in there would be OK, but drums or electric guitar would sound pretty lousy. Drums need space, air, life, to sound good, but the decay time in that room is only 270 ms, IIRC. Excellent for a control room, but drums would sound dull in there.
On the other hand, if you treated your single-room such that it was lively enough for most instruments, then it would be terrible for mixing and mastering. You would lose all the subtle clues that are so very necessary for being able to mix well, and absolutely essential for mastering.
Third option: compromise. Treat the room so that it is a bit liver than it should be for a control room, but a bit deader than it should be for instruments. And then you'd have a room that is lousy for both!
There's one other option: variable acoustics. It is possible to design treatment devices that can be open/closed/flipped/rotated/slid/covered/uncovered/etc., to expose different acoustic materials to the room, for different treatment options. It should be possible to design a set of devices that, when oriented in one manner, provide the perfect environment for mixing and mastering, but when moved to other configurations give you a broad range of variability, to meet any need for pretty much any instrument. I'm not talking about a couple of gobo's on wheels here! I'm talking about something rather more sophisticated: specifically designed modules, attached to the walls and ceiling, in specific locations, with specific tunings, to produce the correct acoustic response for a control room in once configuration, and a broad range of other responses in other configurations. I have designed a few such devices for some of my customers. They work, if designed properly and built carefully.
I like the option of having a dead booth for doing drums
Drums really don't sound good in dead spaces, even when close-mic'd. They need "air" to sound good. A while back Sound on Sound magazine did a series of tests in several studio live rooms around a big city, with the exact same identical drum setup in all cases, with the exact same song played by the same well-known drummer, in the identical manner, as near as he possibly could. And the results are rather surprising. You might want to google that, and listen to the actual tracks. They had both close mics and also ambient mics. The big rooms sound fantastic with both sets of mics, but the smallest room doesn't sound that good at all, on either set...
I think I'm weakest on HVAC concepts, but as far as I can understand, I should be able to use the storage room/sound lock as an exchange chamber for a wall mounted air conditioner.
Not for a facility that big! Rod's "exchange chamber" concept is meant for home studios, with just one or two small, low-volume rooms. You are going to need a proper HVAC system for you place, specifically designed to move the right volume of air through each room at the right speed, while dealing with the real sensible heat and latent heat loads in each one, and able to handle the "worst case scenario" for each room without being overwhelmed, while also able to handle the normal and smallest loads without being "underwhelmed". That's quite a challenge, and not doable with an exchange chamber, for that size facility.
***a large control / tracking room (full of obscene amounts guitars, synths, amps, percussion, pianos/keyboards etc),
... which will happily sing along with your music, as you try to mix and master, adding their own robust tones to the perfect, pristine sound coming form the speakers, and muddying it up to unspeakably bad levels.
Seriously, I never have figured out why people would go to all the trouble and expense of building a great control room with great acoustics to be able to mix perfectly well, with no coloration at all from the room... and then they throw in a whole bunch of resonant, reverberant, ringing, singing things that totally mess that up! Then they wonder why they can't seem to turn out good mixes... Sort of like building a beautiful swimming pool, with a top filtration system to keep the water crystalline, sparkling... then throwing gobs of mud, ink, paint, blood, garbage, and raw sewage into it, to make it more interesting...
OK, < RANT-MODE = OFF > ... but I'm sure you get my point. If you put anything in the control room that changes the room acoustics, then why even bother having a control room? When I was working on that room that I linked you to above (Studio Three), with the owner, we spent a lot of time doing numerous acoustic tests with all kinds of things that he wanted in the room, everything from furniture and even down to ornaments on the desk, as he wanted to be sure that nothing in the room would mess with the acoustics. Some things got to stay, other things had to go. Who would think that a small desk ornament could screw up the response? But it can.
I would urge you to NOT keep those things in your control room. By all means, have them in there when you need to record them, but then take them out and store them elsewhere when you need to mix.
ideally with some life to it for fun tracking, but controlled enough to mix in (at least at the mix position)
"I want a road for my car that has the perfect surface to race Formula 1 cars on, bringing out their best performance and top speed, but is also sufficiently muddy, steep, rocky, full of roots, boulders, and holes, with sharp dips and curves, lots of trees, gravel, and sand, so it is great for my off-road bike. The road I want must be perfect for both!". Yup. good luck with that!
I think you get the point I'm trying to make. You can't have it both ways.
***a small storage closet / sound lock / HVAC exchange chamber
You absolutely do need the storage, no argument, and for a facility that size, it will need to be quite large. But you do NOT need a sound lock: if you design the studio correctly, each door is it's own sound-lock, so having an entire separate room as a sound lock is superfluous, wasted space, and wasted money. It also messes with your access paths and traffic flow: Load-in and load-out should have the simplest, most direct path possible, and having to drag heavy, bulky, delicate, expensive gear through multiple doors and a separate sound lock, is not helpful.
I haven't' figured out how to use sketchup well enough to draw double framed two leaf walls yet,
There's a number of good tutorials about SketchUp on YouTube. If you work through those, you'll get a good handle on it. The key points are to make each new object you create into a "component" immediately, then to assign it to one or more "layers" that are organized meaningfully and logically. Using guidelines helps a lot when scaling, sizing, and moving components. Use "Scenes" to control the visibility of various sets of components, from various viewpoints.
If my starting interior shell dimensions are those, what sizes would be smartest to do for these 3 rooms?
I think you mean "If the starting interior dimensions of my outer-leaf shell".... Sorry to split hairs like that about terminology, but it's confusing to take about "interior dimensions" when you are asking how to build the inner-leaf!
our height is 11'6" to the bottom of the joists, ... If we do the independently framed ceiling, it looks like our effective ceiling height would be 11'1".
Using what size lumber for the new ceiling joists? Did you check that those dimensions are suitable for carrying that dead load and live load (what load?) with that span using that type of wood? What deflection are you allowing for with that calculation? If you think I'm talking Greek, and didn't understand much of that, then there's a problem. You need to know all of that in order to have determined the size of your joists, to ensure that they have enough structural integrity to safely (and legally) carry the load, while also providing the amount of isolation that you need (which we don't yet know, until you get your sound level meter out and do some tests... )
Since you already know what your ceiling height will be if you do it that way, you must have already done all those calculations....
On the other hand, if you were to build your inner-leaf ceiling using the "inside-out" technique, the acoustic height of the room could be around 11'4", give or take a bit, independent of the joist sizes that you end up needing. Plus, you'd have all the advantages that an inside-out ceiling produces anyway...
Would it be worth it to pour our slab a foot down from the live room to get that extra foot, or will 11'1" be enough to get happy?
Did you do the math? What ratio are you basing the room dimensions on? Sepmeyer? Louden? Boner? Is it in the Bolt area? Is your Bonello chart smooth? Does it pass the critical three BBC tests? Once again, if all that is Greek, then you have a problem. On the other hand, if you know what all of those are, but don't know how your room relates to any of them, then you also have a problem....
As far as I can tell, it's right on the edge of being too short to be ideal.
How did you arrive at that conclusion? On what basis?
Exterior Finish : My stucco guy is going to be patching up the holes in the outside walls, because there are 4 doorways we are filling in, as well as some vents. Should I be having him just try to match what's already there? Anything else I should be having him do to the exterior besides make it airtight?
Excellent! Get him to make it as thick as possible all around, and make sure he actually fills all holes, gaps, and cracks, instead of just skimming over them with a surface coat. Attention to detail, and perfect seals are critical aspects.
Exterior walls and inner shell : My thought is to do a two leaf, double wall system on all the exterior walls (and ceiling), by filling all the existing joist bays with 3 layers of 5/8" drywall, caulking w/backing rod all around
The concept is right (fully-decoupled two-leaf isolation system), but how did you determine that you need three additional layers of drywall in there, if you don't yet know how much isolation you need? What frequency are you tuning your walls for? What level of isolation will they provide? What is the lowest frequency that you need to isolate? Doing the math is critically important... If you didn't do the math, then you have a problem: You are building a wall, and you have no idea if it will do what you want or not. And it might well do what you want, but you might also be spending the other half of that bazillion dollars you mentioned, unnecessarily.
and cover the inside w/2 layers of 5/8" drywall.
Why two layers? Why not one? Or three? Or four? How did you arrive at the conclusion that 2 layers will give you the right MSM frequency and the right amount of isolation?
will it be enough for us to get away with some loud stuff when neighbors are home?
Let me put that question back to you, in other terms: "If I cut a piece of string at random, with my eyes closed, just sort of guessing, will it be long enough to get from here to there? But I can't tell you where "here" and "there" are yet, because I don't know, as I can't find my tape measure"....
That's what you are asking us. You don't know how much isolation you need because you have not measured how loud you are or how quiet you need to be, you haven't told us what frequencies you need to isolate, but you are asking us if what you propose will be "good enough" to achieve a goal that you have not yet defined!
Doors : I'm thinking of using a combination of sliding glass doors and SuperDoors for the doors -
Once again, that decision should be based on how much isolation you need, but this time, it's how much you need between rooms. That's a basic spec for starting the design process. If you have not yet set your goals, how will you be able to design walls, doors, windows, HVAC and electrical to meet those goals?
It's one thing to design a studio for 30 dB isolation, and a very, very, VERY different thing to design it for 90 dB isolation. That's roughly the same as the difference between stopping a kid on a skateboard, and stopping a freight train. And I'm not joking there: that really is a comparable scenario, in terms of energy that you'd need to dissipate in each case.
Interior Walls : I'm not sure if I should do a single stud or double stud construction for the drum booth and storage closet rooms. I think there's enough space to do either, just curious if it'd be workable to keep these walls simple and mostly focused on controlling tracking ambience instead of extreme isolation.
You already said that you plan to do those as proper two-leaf fully-decoupled MSM isolation systems, so I'm just not understanding why you would want to put double studs on one of those walls. Maybe I'm missing something here? Perhaps I didn't get the question you are asking?
Electrical : I'm thinking of getting into the room through the slab, and then doing my runs (both to outlets and light fixtures) exposed on the inside walls via conduit, to not puncture the shell.
Are you planning to do the inner-leaf walls inside-out or conventionally? If you do them conventionally, it might look ugly to have conduit running all over the place on the surface of your walls, but if you do them inside-out, that's a possibility. However, in both cases I normally prefer to use a structured raceway system, such as one of these:
http://www.calcentron.com/Pages/fram-tr ... aceway.htm
http://www.export.legrand.com/EN/dlp-wa ... ng_95.html
Much neater than conduit! More expensive, but the aesthetics are worth it, I think.
Soffet mounted mains : should I consider?
Absolutely! Soffit mounting is arguably the most important, best single thing you can do to improve room acoustics. It eliminates all of the artifacts associated with having the speakers inside the room, since technically they are NOT inside the room when soffit mounted.
I've always used near fields, but with a room this size would having some soffeted speakers be smart?
You can soffit mount near-fields as well, if you want...
Of course, in acoustic reality there's not really any such thing as a "near field speaker": it's basically just a marketing term, not a defined technical term about speakers. If you ask four different manufacturers for their definition of what a "near field monitor" actually is, you'll get six different answers, most of the mutually exclusive! If you don't believe me, google that; "Definition of near field monitor"...
Here's a smattering of definitions that Ive picked up over the years, not one of which is true:
"Near-field monitors are short throw, narrow dispersion, limited range units."
"Nearfield is a reference to the range of frequencies the speaker is capable of replicating."
"Nearfield monitors are designed to be positioned approximately one to two metres away from the listener"
"Near-field: a compact studio monitor designed for listening at close distances, typically between three and five feet"
"Nearfield monitors are designed to sit on or just behind the meter bridge of a mixing desk, within a couple of feet of the engineer"
"Nearfield monitors are small speakers which you sit fairly close to."
"Nearfield is if your ear is closer to the speaker than it is to any reflective surfaces."
"The whole point of small near field monitors is that you sit close enough that you don't need a treated room. Amazing how many people don't seem to get that"
"Near-field studio monitors are small speakers that minimize the effects of your room on the sound source."
"For nearfield monitiors, you need a listening distance that's at least 3 times the distance between the woofer and tweeter"
"Near field monitoring is a way to sit closer to your monitors with the idea that sitting closer to the speakers say 3′- 4′, will reduce the sound of the room in the mix."
"Nearfield simply means "close distance."
"Nearfield means so close that the SPL no longer increases if you move even closer."
"Nearfield means less than 2.50 meters
"Near field is the critical listening distance"
"Nearfield means that your ears are closer to the speakers than they are to any of the room boundaries".
"Near field refers to the size of the monitor in relation to the listening distance"
"Near-Field monitors are designed to be placed less than 6 feet away from the listener."
"Near field listening: set them up 4 feet apart, from 4 feet away. They will sound great regardless of the room from that close".
"Nearfield monitors"? = No bass, no hope of bass, let's not pretend."
What a wonderful hodge-podge of garbage answers! Most are totally off, a couple get sort of close, but they are all still absolutely wrong! And mostly they contradict each other. The worst thing is, all of those come from "experts" offering thier opinions on how to set up speakers and rooms...
The issue is that there's no such thing as a "near field" monitor anyway, since the term "near field" refers to the ROOM; not the speakers. If your head is closer to the monitors than the critical distance for the room then you are in the near field. If you are beyond the critical distance, then you are in the far field. Period. That's it. The "critical distance" is a well defined technical term that marks the boundary between the direct field and the reverberant field, in any given room. It can be predicted mathematically, and it can be measured. There's no question about where it is, or what it is. That distance varies for each room, and each set of treatment, but does NOT vary for different speakers in the same room. For a smallish to medium room that is very well treated, the entire room might be in the near field, but if you take out the treatment then the near field might only extend a couple of feet beyond the speakers. In a small, badly treated room that is poorly laid out, there might be no near field at all. And in a large room, the near field might extend several meters, even with minimal treatment.
In other words, "near field" is all about the room regardless of the speakers. If you set up some so-called "mid-field" speakers in a room that is well treated, you WILL be in the near field, and those things are now, therefore, "near-field monitors", regardless of what it says on the box. But put those same speakers on a large room that is poorly treated, and you might find that you are in the far-field, just a couple of feet away!
Using the term "near field" for monitors is marketing hype. Nothing more, nothing less. There is nothing at all that you can do to a speaker to ensure that it will always be a near-field monitors, since that depends entirely on the room, and on where you place the speakers and your head in that room.
Sorry about the rant again! But my point is that you can use pretty much whatever speakers you want to use in your room (within reason!), regardless of what it says on the box they came in. You do not have to listen close to near-fields, and you do not have to be 20 feet away to listen to far-fields. And you can soffit-mount pretty much any speaker you want to, with only a very few exceptions. So chose the best, acoustically flattest speakers you can get, with the spectrum range that you need for your music, put them in properly designed soffits at the correct locations in the room, and then design the room around them.
When I'm designing a room, one of my big priorities is to make sure that the room works with the speakers. They should complement each other, smoothly not fight each other. If the owner insists on certain specific speakers (many do), then I'll look at their characteristics and take those into account in the design, setting angles, distances, and treatment in meaningful ways to control the way sound propagates from those around the room, and also to load them as well as possible, acoustically.
HVAC : This is my weakest area of experience. I try to read about it and my head spins. Would it work to put a wall mounted AC unit in the storage closet, and have fans exchange air w/both the control room and dead booth?
Nope!
I'm thinking $35K - 65K for this first phase? Does that sound reasonable? Scope of work is : Slab, Reinforcing exterior walls, building interior walls, 2 sliding doors (if we double it up from the iso to main hall), one SuperDoor, and 2 Slightly-Super-Doors, Electrical, HVAC, Audio Wiring.
Your budget is reasonable for the first phase, yes, but your priorities are a bit off. Before you do any of the above, you need to design the entire studio first, in all detail, down to the last stud and fraction of an inch. Anything less, and you'll be throwing 65k up in the air, hoping some of it will land somewhere useful....
Design, design, design. Those are the three most important aspects of building a successful studio. One acoustician for whom I have great respect, has a motto: "Building a studio is 80% design, 20% construction". It might sound like a joke, but he's absolutely right. If it is designed properly, then the actually construction will be a breeze: fast, simple, effective, cheap. But if the design is poor (or non-existent), then construction will be slow, unsure, problematic, and very, very expensive, with an uncertain outcome.
All I need to do "work" is the phase 1 stuff, so we can get through our first phase and then figure out what we want/need/can afford to do for step 2
Sorry, but that's backwards, and a recipe for disaster. It just is. I hate to be so blunt, but there's no other way to put it.
Here's an analogy: "All I need to do now is to go on vacation, so phase one is to get in the car and start driving, then figure out where I'm going and how much it will cost and what to take with me and if I can even afford it, after I have already driven a few hundred miles." In effect, that's what you are saying. You are heading for a goal, but you don't know what it is, where it is, how to get there, or how much it will cost.
Are there any key considerations I should have while doing phase 1 that will impact how we approach the second step?
Yes: The ONLY consideration you need to take into account is to design ALL of it first, completely. All other considerations will become apparent as you progress with the design.
So I don't have the resources anymore to pay a fabulous designer and construction team to build
You said you are thinking of a budget around 60k for the first phase, and I'll assume about twice that for the second phase, so a total in the ball-park of around 150k - 200k. I'm not sure what type of rates you think we studio designers charge, or what you have been charged in the past, but there's PLENTY of room in your budget to get a good design done. I'd suggest talking to John Sayers, and asking him to quote for doing your place. If he can't, then let me know by PM and I'll put you in touch with others who can. But do watch out for unsolicited offers from folks claiming to be forum members and studio designers, offering their services without you having asked! I've seen some evidence of that on the forum lately: there seem to be a couple of unscrupulous "members" here, who reach out to unsuspecting real members, such as yourself, ... watch out for those guys! Talk to John or to me, and we'll guide you to folks who actually will do a good job designing your place. You will make the contact with them; they won't contact you first.
it's going to be as DIY of a build as possible, and I want to keep our expenses as low as we can
That's fine for the construction, and also for the design if you have the knowledge and the skills. But an experienced designer can save you money, many times what he charges you for the design fee. He will help you avoid the typical (and expensive) pitfalls and mistakes that most DIY studio builders fall into. Just having to tear down and re-build one wall that you got wrong the first time can cost you thousands of dollars, that you could have avoided spending if you would have had a good design in the first place. And spending nearly 200k, only to have mediocre results because you tried to save on a small percentage of that for the designers fee, does seem a bit short-sighted....
I plan on having this space serve as a creative home base for my wife and I over the next 20 - 30 years.
OK, another paraphrase: "I plan on spending 200k to make this my dream studio for the next 30 years, my life's project, the very reason I exist, but I don't want to spend a few extra grand and a few extra months to make sure that it is designed properly, and will actually be a place that I really can use for the next 30 years... or even use at all! I'd rather take my risks, save those few grand, and just hope that, purely by chance, it sort of turns out to maybe be roughly a vague approximation of something that might possibly sound somewhat acceptable, perhaps..."
Hmmm....
Not trying to be a wet blanket, or rain on your parade, but from my objective viewpoint, far away from your project, that's the way I see it. In your shoes, with that budget and that goal, I'd be on the phone to John or another designer right now, begging him to design the place, to ensure that it really does work, and really will have good enough acoustics that you'll be able to use it for the next 30 years.
Sorry to be so "in your face", but sometimes that's the best way to get someones attention. You are planning to invest a large sum of money, so I would strongly suggest that the very best thing you can do is to set aside some of that to get a good designer, such as John, to design it for you. And I'm betting that however much he charges you, you'll save that (and more!) from having it done right, and not making mistakes.
- Stuart -
All I need to do "work" is the phase 1 stuff, so we can get through our first phase and then figure out what we want/need/can afford to do for step 2. Are there any key considerations I should have while doing phase 1 that will impact how we approach the second step?