Salt Lake City, Utah Home Studio Design

Hi John! I really appreciate your willingness to help people out with their studio design, thank you! Here's my situation.. I have just about 975 sqft in my unfinished house basement. The majority of the exterior/foundation walls are framed in with wood studs. The majority of the space I have to work with as 9 ft ceilings, and a smaller part has 8 ft ceilings. The floor are concrete, heating/air vents are in the floor. Electrical has NOT been done (though I am an electrician and will be running the clean power myself) I'm looking to build 2 studio rooms out of the space, one mixing/control room and one large live room. I intend to record acoustic drums in the live room, and full rock bands all at once in one room. This studio will be used occasionally for business but mostly for my personal 5 piece rock band to record. My recording setup does NOT include a large format console, simple daw controller, modern desk, high end pres, converters, and Adam A77X's as my main monitors (however I may upgrade to Focal SM9's in the future). Sound isolation isn't a big concern for this project, maybe a little extra isolation between the control room and live room but the rest of the house is used to having a loud rock band rehearsing 4 nights a week, neighboring houses are far apart, so that's not a concern. We are a very loud rock band easily reaching 110 db in the small 300 sqft room we currently record and rehearse in. The only "extra" isolation i'm interested in doing is decoupling the ceiling with faring channels. I own a mac so I can't use the recommended drawing program, and I don't have the time to get fluid with sketchup, so I hand drew and accurate floor plan. In the floor plan, it illustrated where the 9ft ceiling portion is and where the 8 foot ceilings portion is. The dotted lined wall in the middle of the diagram is a main support wall that can be removed replaced with a floor or ceilings beam. The other dotted lined wall at the bottom right corner is the "cap off" wall, that can be angled or adjusted give or take 4 ft or so. The bathroom is going have to stay the way it is with the exception of where the door is. Budget: Small but that's a tricky questions for me due to the fact I have a side job at a local lumber supply store where I can get drywall, wood, paint, flooring, and such things at a good discount. Lets pretend I don't at say around $5000, give or take a few grand? I really don't know what it is going to cost to do what I want to do. All labor will be done by myself and friends, so that helps the final price budget allot. Here's the space.. http://i295.photobucket.com/albums/mm150/ch-holt/SmallStudioLayout.jpg Also, heres a video walkthrough of the space http://www.youtube.com/watch?v=yvLl_dHweF0 Questions.. 1. What should the geometry of the rooms be for this space? 2. What layout would you do with this space? 3. Can I get away without doing a "room in room" design and still have professional acoustics? 4. Is the "room in room" designs the only way to angle/shape ceilings? 5. Do I even have enough cubic footage to have a great tracking room for drums and bands? Or should I just build control room and track in a professional studio?

Nobody?

Hi "chrish", and welcome to the forum! :) Wow! I don't know how I missed your thread! I guess it's just one of the ones that slipped by unnoticed, unfortunately. So thanks for bumping it!

I have just about 975 sqft in my unfinished house basement. The majority of the exterior/foundation walls are framed in with wood studs. The majority of the space I have to work with as 9 ft ceilings, and a smaller part has 8 ft ceilings. The floor are concrete,

That sounds like an excellent space for a studio. Decently high ceilings, and a great floor.

heating/air vents are in the floor.

That might be a problem: maybe you could post more info about that, and perhaps some photos?

Electrical has NOT been done (though I am an electrician and will be running the clean power myself)

Great! One word: star grounding. That's part of the secret to reducing the chance for hum and ground loops in studios.

I'm looking to build 2 studio rooms out of the space, one mixing/control room and one large live room. I intend to record acoustic drums in the live room, and full rock bands all at once in one room.

That implies two things: 1) You need major isolation, and 2) the live room should probably have a somewhat "dead" acoustic response, to aid in getting cleaner recordings with many instruments in close proximity.

and Adam A77X's as my main monitors

Oh Yeah! Now we talkin! :) :thu: (Sorry, I'm just a big fan of Adam speakers!)

Sound isolation isn't a big concern for this project, maybe a little extra isolation between the control room and live room

That's surprising. I find it really hard to get good drum recording when I can't clearly hear the drums on the CR monitors all by themselves, with no bleed through the walls from the actual drum kit. I know that doesn't bother some people, but personally I find it annoying and a bit frustrating if I can't hear just the mics by themselves on the monitors. There's also the issue that you can't really increase isolation between the rooms unless you also increase isolation to the outside world for both of them. It goes hand in hand, generally. The only way of doing that would be to isolate only the live room by itself, and not isolate the CR at all: leave it as part of the house. But that brings its own set of drawbacks.

We are a very loud rock band easily reaching 110 db in the small 300 sqft room we currently record and rehearse in.

Are you measuring on "C" weighting, slow response? If you are only clicking 110 dB like that, then you aren't so loud. The drums alone can put out 115 dB with a loud player, so adding in all the rest can take you closer to 120. If you are measuring on "A" weighting, then that basically ignores the drums and bass, so it isn't telling you the full story...

The only "extra" isolation i'm interested in doing is decoupling the ceiling with faring channels.

Furring channel alone (also called "hat channel") does not decouple. If you want to use furring channel, you need RSIC clips or something similar (Whisper clips, Isomaz, etc.) to do the decoupling. Or you could use proper resilient channel instead, which looks similar to hat channel, but is not the same at all, acoustically. Also, decoupling just the ceiling by itself won't do much to isolate. Your outer walls are wood framed, and without any inner walls those will just flank all of the sound right around your decoupled ceiling. Sound is sort of like water, in some aspects: it takes the easiest path. So if you put a big barrier in the way but there is an easy way to bypass that barrier around the edges, then that's the way it will go. So just doing your ceiling alone won't accomplish much.

I own a mac so I can't use the recommended drawing program, and I don't have the time to get fluid with sketchup,

There is a version of SketchUp for Mac, and it doesn't take that long to learn the basics. A few hours, maybe. There are plenty of good tutorials on YouTube as well, to help you get started.

so I hand drew and accurate floor plan.

That's great, but sound is 3D, not 2D, so it is a lot more use if you model your space fully in 3D. You'll need to do that anyway, once you get to figuring out the correct geometry for your control room, speakers, desk, walls, ceiling and listening position. That's practically impossible to do in 2D on paper, since the reflection angles are compound: sounds moves around the room in 3D.

In the floor plan, it illustrated where the 9ft ceiling portion is and where the 8 foot ceilings portion is. The dotted lined wall in the middle of the diagram is a main support wall that can be removed replaced with a floor or ceilings beam.

Based on that, I would suggest using the smaller "8 foot" side for the CR, and the larger "9 foot" side for the live room. Height is also more use in the LR than the CR, so that works out well too.

The bathroom is going have to stay the way it is with the exception of where the door is.

Looks like there shouldn't be any problem there.

Small but that's a tricky questions for me due to the fact I have a side job at a local lumber supply store where I can get drywall, wood, paint, flooring, and such things at a good discount.

That's a really good thing! If you are doing the work yourself, then it's hard to get cheaper labor than that, so there's no way to save money there, so being able to save on materials is very useful.

Lets pretend I don't at say around $5000, give or take a few grand? I really don't know what it is going to cost to do what I want to do.

OK; this is where a lot of projects start to run into problems, so its important to get this bit right. The best way of figuring out the real cost, is to call a couple of local contractors and ask for their "flat rate" per square foot for converting an unfinished basement into a home theater (minus the equipment: just for materials and labor), then add about 20% to that. You'll get a realistic figure of what it would cost if you were to get a contractor to do it. However, in your case you have free labor (you!) and discounted materials, so it is going to be much cheaper than the contractor rate. The question is: How much cheaper? That's hard to say, unless you can convince a contractor to break down his quote into two items: labor and materials. But since you are involved in the building industry, you probably already know roughly how much labor and materials cost, so you can probably come up with an estimate. But think of this: 5 grand for a thousand square feet, works out to about 5 dollars per square foot.... I'd say that even with free labor and discounted materials, that is still on the low side. Even if all you did was to lay laminate flooring, that already runs 2 to 3 dollars per square foot., so that would eat half your budget right there, just in flooring. Drywall is about $10 per 4x8 sheet (5/8" fire-rated), and you'd need about 65 sheets to do the ceiling (assuming no wastage), so there's another $700, not considering the RSIC clips and hat channel (or resilient channel), insulation, screws, caulk, backer rod, tape, mud, etc. Then there are the inner-leaf walls (studs plus more drywall), doors, windows, electrical, and perhaps the biggest expense of all: HVAC. So I'd say that 5 k is on the low side.

1. What should the geometry of the rooms be for this space?

Since you are on a very tight budget, I would just go with a simple rectangular control room, using one of the good ratios. Maybe one of Sepmeyer's ratios would work. The same for the live room: just a plain rectangle, and using a ratio that is distant from the bad ones.

2. What layout would you do with this space?

As above: But the CR where the ceiling is lower, as height is more important for the LR. Try to arrange it so you have good sight lines straight ahead from the CR into the LR.

4. Is the "room in room" designs the only way to angle/shape ceilings?

"Room in a room" is for isolation, and can be done in many different shapes. The simplest (and cheapest!) is just with using a plan rectangle for the shape of the room. Your budget probably won't go far enough to do fancy things, like shape the front of the room for RFZ, so I would just stick to a very simple rectangular shape for both rooms, and yes, you do need to do them as "room-in-a-room", to get good isolation, regardless of what shape you make them.

5. Do I even have enough cubic footage to have a great tracking room for drums and bands? Or should I just build control room and track in a professional studio?

Yup, you sure do! Your LR area seems to be about 500 ft2, and with a 9 foot ceiling, that's 4,500 ft3. Pretty good! Not for a very big band, to be sure, but you can still fit in a five-man band quite comfortably. Of course, the final room will be smaller than that, once the inner-leaf walls and ceiling are in, but still very usable. John has built tracking rooms inside shipping containers, very successfully, and your space is quite a bit bigger than that! So overall, I'd say that you have a good space to do what you want, and realistic goals, but that your budget is on the low side, and probably needs a shot of adrenaline and some steroids to get it on track. One option might be to spend that budget on just one of the rooms, then do the other one alter, once more resources become available. - Stuart -

No worries, Thank you for taking the time to reply. Lots of great info. I will post photos of the floor ducts soon. Isolation from the CR and LR: The reason I thought I didn't need great isolation is due to the fact I've been working out of a small "one room studio" for about 6 years, where the tracking room is the mixing room, and the drummer is about 10 feet away from you. Is what I would do is set the mics up, have the drummer play, then listen back to see what's going on, fix mic postions/change mics, repeat cycle. So whats the difference between referencing playback in the same room and having an isolated CR to monitor live in? Will you fill me in on all the benefits of having a greatly isolated control room? I feel like a newbie all over again. Room within a Room design: The CR is going to have to be a "room within a room" design anyway due to the heating and air ducts on the ceiling. How quite we talking when you do room within a room builds? The master bedroom directly above the LR. I will learn sketchup! Budget: Where should I be realistically? Why would I need to do HVAC? It'l already there and piped in. My brother in law does HVAC though, so theres another discount, if I have to. My old studio had no HVAC, haha. Room Geometry: If I wanted to go a little beyond basic rectangular rooms, how would I go about knowing how to do the geometry for an RFZ control room and such? And how much extra are we talkin? I mean, I'd like to start with good room acoustics to start with to an extent, and leave treatment as the last step. Extras: I would like to do a glass sliding door in between the rooms, that would double as the window looking into the LR. How does that work when put in-between two "room in room" designs?

The reason I thought I didn't need great isolation is due to the fact I've been working out of a small "one room studio" for about 6 years, where the tracking room is the mixing room, and the drummer is about 10 feet away from you.

Ouch! :shock: :!: That can't have been too much fun...

Is what I would do is set the mics up, have the drummer play, then listen back to see what's going on, fix mic postions/change mics, repeat cycle. So whats the difference between referencing playback in the same room and having an isolated CR to monitor live in? Will you fill me in on all the benefits of having a greatly isolated control room? I feel like a newbie all over again.

I think you answered your own question, without realizing it! You avoid wasting all that time on the "rinse, repeat" cycle. Since your drummer will be wearing headphones, and you'll have a talk-back mic in the CR, you can do the whole thing in real-time, without needing to record a bit, stop, rewind, play listen, rinse, repeat. That's a lot of wasted time! And if you get an assistant in the drum booth along with the drummer, also with headphones on, then he can adjust the mics while the drummer plays and you give them both instructions on your talkback.... it can just go so much faster like that, and much smoother. Also, since you were in the same room as the drummer before, your hearing was suffering temporary damage from the "live" playing, without their being enough time for it to recover to be able to properly hear the playback. So now you'll be listening to the drums with fresh, undamaged ears, able to hear all the subtleties that you might have missed before. Then there's the just plain "hearing damage" thing: Drums kill... your hearing. Drums easily hit 115 dB, but according to OHSA standards, after 15 minutes of that you have irreversible hearing damage, which accumulates over time. The more often you are exposed to those levels, the worse it gets. You did that for 12 years, so I'm betting that if you went to an audiologist and got them to graph your hearing, you'd already see the effects of that. And since you are a sound engineer, your ears are your biggest assets! It just pays to take care of them, and avoid any further damage, as time goes on.

Room within a Room design: The CR is going to have to be a "room within a room" design anyway due to the heating and air ducts on the ceiling. How quite we talking when you do room within a room builds? The master bedroom directly above the LR.

You can conceivable get around 60 dB of isolation, if you do things right. Laboratory tests show that you can get even more than that, but realistically, low 60's is about as far as you can go in a typical house. But that's huge! 60 dB of isolation will knock your 115 dB drums down to 55 dB, which is 5 dB quieter than ordinary conversation. Even if you only manage 50 dB, that's still Pretty Darn Good, since it only gets better as you move away from the wall. Isolation tests are measured 3ft from the wall, but air attenuates naturally as well, so the further you step back from the wall, the quieter it gets. At 15 feet, you are theoretically another 6 dB down. So it is feasible to get high levels of isolation with proper "room in a room" construction. In fact, that's the most economical way of getting good isolation.

Why would I need to do HVAC? It'l already there and piped in. My brother in law does HVAC though, so theres another discount, if I have to.

You seem to have all your discounts neatly lined up! :) Cool! OK, you need HVAC because "room in a room" implies that there are two totally air-tight seals around you: the outer-leaf and the inner-leaf. The are both absolutely hermetically sealed. So no air goes in or out. And since you and your clients/friends sort of do need to breathe, you do need to bring in fresh air and get rid of the stale air. To do that, you need to chop huge holes in your carefully sealed isolation walls! :shock: So to retain your high isolation while still allowing air through, you need to put "silencer boxes" on those places where your HVAC ducts go through your isolation walls. And you need to put a fan on there some place, to make the air move. And you need to dimension things correctly so that the air moves slow enough to not create any sound of its own. That's why I said that the HVAC registers in your floor might be an issue: They need to have silencers on them, in order to keep your 115 dB drummer noise from getting into the duct system of your house, and popping out in every single room, very annoyingly. That's what silencer boxes do: allow air to go through, but block sound. You can build them yourself: not hard at all. But they do have to be designed right, to do the job. Then there's the issue of cooling and humidity: the above is only about ventilation (getting fresh air in / stale air out), but you also need the actual air conditioning part to control the humidity in your room, and the temperature. Half a dozen musicians jammed into a small room, and jamming away spiritedly at a great song, can produce a lot of heat, and a lot of humidity. The human body puts out anywhere between about a hundred watts and over a thousand watts, for strenuous exercise, which is like having a couple of heavy duty space heaters in your room.... Unless you remove it, that heat has no place to go! Your room is wrapped in thick acoustic insulation, which is really great thermal insulation too. So the job of the HVAC system is to take care of the cooling aspect, too. Your house very likely already has an HVAC system in it, so you might well just be able to tap into that, rather than add new equipment. If your existing system has the capacity to handle the extra load, then that would probably be the way to go. If not, you could put in a couple of mini-split systems to do the job.

My old studio had no HVAC, haha.

Right! But it also had no isolation... :)

If I wanted to go a little beyond basic rectangular rooms, how would I go about knowing how to do the geometry for an RFZ control room and such?

There are quite a few threads here on the forum about that. If you search for RFZ you'll probably find way more than you ever wanted to know about it! But the basic concept is to angle the front wall and parts of the side walls such that no reflections can reach your ears until at least 20 ms after the direct sound, and at 20 dB quieter. That's hard to achieve in the home studios, so relaxing it to 15 ms and -15 dB is reasonable. So you angle the walls and ceiling to accomplish that: Of course, that makes it harder to build, since your framing now runs at strange angles in places, but it certainly does make for a much better control room.

And how much extra are we talkin?

It's hard to say how much extra that would cost in materials: I'd guess that it adds maybe 10% - 15% more. The biggest issue is labor, since you need to cut all of those angles very carefully. It slows the build down, but improves the final result.

I mean, I'd like to start with good room acoustics to start with to an extent, and leave treatment as the last step.

You can do that, for sure, but RFZ isn't only treatment: you angle parts of the actual physical walls of the room, as well as part of the ceiling. So it has to be done in the design stage, and the construction stage.

Extras: I would like to do a glass sliding door in between the rooms, that would double as the window looking into the LR. How does that work when put in-between two "room in room" designs?

It works very well! :) What you do is to put a pair of doors back-to-back with a small air gap between them. One door is in the inner leaf and the other in the outer leaf (from the point of view of the room you are in! the "inner-leaf" of the control room is sort of the "outer-leaf" for the live room, an vice-versa...). If you look at John's own web site, you'll see many examples of how to do sliding glass doors between rooms: http://www.johnlsayers.com/ Some forum members have done the same thing in their studios, so if you search through the build threads, you'll see some of those, and how they did. - Stuart -

Thank you, Soundman! That was very informative and helpful. Questions: RFZ Designed Control Room 1. Can I learn how to design one on my own? If so where can I find the info? I've searched this forum and can't find explanations on how to make one. Or is it something a professional has to design in order to work? Live Room Geometry 2. From what I've learned the live room should just have non parallel walls, either angle one opposing wall 12 degrees or both 6, is that correct? Would should I do with the ceiling?

Thank you, Soundman! That was very informative and helpful.

:) We aim to please!

RFZ Designed Control Room 1. Can I learn how to design one on my own? If so where can I find the info? I've searched this forum and can't find explanations on how to make one. Or is it something a professional has to design in order to work?

You can learn how to do it yourself, it's not that hard, once you understand the principles of acoustics. RFZ is actually a trade-marked term, but the concepts are usable by anyone (as long as you don't try to sell it as being your own invention!). If you search the forum for "RFZ", you'll find more links than you ever imagined could exist. Follow several of those, and you should start getting the basic idea. Also if you google "RFZ studio design concept", you'll find many links to useful information about it. Of course, if you don't have time to learn how to do it, or just don't want to, then you sure can hire someone to do it for you, but if you do have the time and inclination, it can be very rewarding to do it all yourself, and if you follow the basic concepts, it can work out just fine. Several people here on the forum have done it themselves, very successfully.

Live Room Geometry 2. From what I've learned the live room should just have non parallel walls, either angle one opposing wall 12 degrees or both 6, is that correct? Would should I do with the ceiling?

Live rooms can be parallel or non-parallel, as you prefer. The usual reason for splaying walls 12° (or more) is to prevent flutter echo and perhaps even re-direct modes somewhat, but there are other methods for dealing with both of those issues. So it's more of a personal preference: if you like splayed walls, then splay them! If not, then don't. The ceiling too can be either tilted or flat, whichever you prefer. Rooms can be built as plain rectangles and still be great, acoustically. And rooms can also be built with rather strange angles in them, on all walls and the ceiling, and also be great. To help you get a better handle on all of this, I'd suggest two books: "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. - Stuart -

Thank you, Stuart! So will those books teach me how to build a RFZ designed control room? Or do I still need to search the forums for information?

So will those books teach me how to build a RFZ designed control room? Or do I still need to search the forums for information?

The first book ("MHoA") will teach you the basic of acoustics, pretty much everything you need to know to understand how sound interacts with rooms and other objects, as well as how to design and build treatment for your room, and how to test the room acoustics. The second one, ("Rod's book") is more about actual construction and less about acoustic theory. It teaches you all the tricks for actually building your room. They don't concentrate specifically on RFZ design, but the principles they both teach are very necessary for understanding the RFZ approach. So you'll probably still need to scour the forum for the concepts. I'm not aware of any book that specifically teaches RFZ design, but between those three resources (the two books plus the forum), you'll pretty much have all your bases covered. - Stuart -

Purchased both books, read them both and a few chapters multiple times. What great books! So glad I didn't start construction or planning prior to reading them. I need some professional opinions on a few things though.. 1. The space I have available to build in for my "live room" is 9ft ceiling X 24ft long X 19 ft wide Golden ratio gets the closest to taking full advantage of the cubic footage at 9 X 23.56 X 14.56 at 3087 CBFT. This creates more even/uniform spaced LF modes (67, 62, 61, 47, 45, 38, 23) If I were to take up the full cubic footage available (9X24X19) my LF modes change to (62, 59, 55, 47, 37, 29, 23) and my CBFT goes from 3087 to 4104 gaining 1017 cubic feet. So my question is do I compromise 1017 cubic footage for better LF modes? Or do I compromise LF modes for a bigger room? 2. I understand the concept of an RFZ control room, just not how to correctly apply/design one for my 8X12X17 space I have to work with. Where do I find those instructions? It consists of ray tracing correct?

So my question is do I compromise 1017 cubic footage for better LF modes? Or do I compromise LF modes for a bigger room?

Hmmmm... tough call! But that's what studio design is all about: making compromises in one area to get a benefit in another area. Since this is a live room, I think I'd go for the greater ceiling height and larger volume. If it was a control room, I would go for the better ratio and smaller volume, since it would still be big enough for a good control room. Ratios are not important for live rooms. Or rather, not as important as for control rooms. A live room is supposed to have some "character" and a "sound" of its own that makes it attractive to musicians and potential customers, so ratios are not a big deal. Go for the bigger volume.

2. I understand the concept of an RFZ control room, just not how to correctly apply/design one for my 8X12X17 space I have to work with. Where do I find those instructions? It consists of ray tracing correct?

If you search the forum for RFZ, you'll find more info than you ever knew existed about it! :) Yes, it does involve ray tracing, and the basic idea is just to angle surfaces at the front of the room so that all of the first reflections are well clear of the mix position. - Stuart -

Okay, got it! I understand the 1500 Cbft standard for control rooms. However, givin the space I have for a control is 1600 cubic feet (8X12X17), is that really enough space for a good control room, with a good frequency response? Or am I just kidding myself?

I understand the 1500 Cbft standard for control rooms. However, givin the space I have for a control is 1600 cubic feet (8X12X17), is that really enough space for a good control room,

I'm not sure I understand the question! And it's not really a standard either.... 1500 ft3 is what the ITU, EBU, AES and other organizations imply as being a good volume for a critical listening room, but they don't actually define it like that. The exact term in EBU-3276 is "high quality sound control room". 1500 is just a god reference point, and since your 1600 is bigger than 1500, then yes, it is better! :) But it isn't actually defined as volume: Both ITU and EBU specs specify floor area, not room volume, and they reference the total room to a hypothetical room of 100 cubic meters. ITU-BS1116 specifies that a two-channel room should have a floor area of between 20m2 and 60m2 (roughly 200 ft2 to 650 ft2). It then mentions rules for ratios, and defines how the RT-60 times for the room should be within a certain range, as referenced to that same hypothetical 100m3 room. If you work all that backwards and figure typical ceiling heights, a room with 200 ft2 of floor and a standard 8ft ceiling would be 1600 ft3 of volume. All these specs agree that the room should never have more than 300 m3 of volume (10600 ft3), but there is actually no minimum volume defined, only implied: You could theoretically have a room with 20 ft2 of floor space and 6 foot ceilings, with a volume of 1200 ft3, and still meet the specs! AES goes a bit further, and suggests that "small rooms" are ones of less than 80 m3 (2800 ft3), medium rooms are 80 to 200 m3 (2800 to 7000 ft3), and large rooms are 200 to 300 m3 (7000 to 10600 ft3), ut once again it does not define a minimum volume. On the other hand, John has designed an entire studio to fit inside a shipping container, and it is a spectacular studio! Search for "Spark One" on the forum....Many other forum members have built very successful studios much smaller than the ITU, EBU and AES specs. Even rooms substantially smaller than 1500 ft3 can still be very good. There is no sudden drop-off at a certain size: if you only have 19.9 m2 of floor space, that will not sound any different than a room that has 20.0 m2 of floor space, for all practical purposes, and even at 19m2 or 18m2 or 17m2 there won't be a terrible decrease in room quality. It's a gradual roll-off, not a sudden cliff. What it does mean in practical terms, is that if your space is smaller that then optimal size as defined by ITU, EBU, AES, et. al, then you have to work harder on your design and treatment to get the room to be as good as it possibly can. It does not mean that a 1400 ft3 room is useless, nor a 1300 ft3 room: it just means that they wont be quite as good as the "minimum" 1500 ft3, but they can still be really good. So you don't need to worry too much about the actual volume: it's not a matter of "Oh NO! I only have 1499, not 1500! I'm doomed!" :) If you want more info, then find AES-TD1001, ITU-BS1116-1 and EBU-tech3276 on the Internet. Those are the actual complete spec documents. EBU-274 is also very interesting.

is that really enough space for a good control room, with a good frequency response? Or am I just kidding myself?

Frequency response is a function of both the room and your speakers, so start out with the best speakers you can afford if you want flat response, then plan your room around those, and design the treatment so that the room does as little damage as possible to the speaker response. Flush mounting ("soffit mounting"), for example, can greatly reduce many of the artifacts associated with having a speaker inside a room. Interesting enough, all those specs above don't actually define what the frequency response should be: rather, they define the much more important issue of what the RT response should be (time domain, not frequency domain). - Stuart -

The 1500 ft3 minimum is from Everest.

Thanks Eric! I knew it came from somewhere, but couldn't recall where.... :) (Must be the years catching up with me...) It's one of those things like the 38% "rule", that everyone talks about, and thinks is an absolute requirement, but in reality is more of a recommended starting point. - Stuart -