What's my best option

[robertbonello]

Hi,
i'm at the planning stage of my studio complex, which is being built 2 storeys underground as the second basement of a house. the practise where i live is to build the bottom out of conrete, and move to limestone at the top, so basically i'm going to have a conrete shell to work in. i'm going to float the control room and live rooms on concrete floors(on rubber studs), and build the various rooms up from there.
i've done lots and lots of reading, and there seem to be many options, but I get the impression that a lot of the techniques are for people who already have the area built, and need to construct the studio inside a certain space.
once I'm starting from scratch (work should begin october), what wall construction should i look to have for each "noisy" [i.e. not toilet, kitchen, machine etc...] room? once i'm floating the floors, would it make more sense to build a concrete room up on each floated floor, and then put up properly treated walls inside, which would obviously be acoustically designed? that means if i'm building, should i build(out of concrete bricks) separate rooms, and then work inside those, or should i just have one big room with "islands" of floated floors, and construct the complex out of wood and everything else that goes with it (all the studded drywall, instulation, chipboard etc etc etc on wooden frames)

AND... if i were to have my control rooms and live rooms built up with (hollow) conrete bricks as the shells, what about ceilings? would these have to be floated on the inner(wooden etc etc) shell of each room, or could i work resting on the concrete walls, and hang/insulate the ceiling as normal?

i have a bit of extra space to work with, so depending on how it makes sense to build, i reckon i'd be able to get it done(provided it fits my budget, which is NOT a lot)... so i'm obviously looking for what's going to make my life easier(i'm going to do as much of the project as i can myself), and ultimately keep costs as low as possible
isolation doesn't HAVE to be 100% perfect... by that i mean i definitely cannot have any leakage between rooms(or to the rest of the building, or surrounding buildings etc) but this is happening 2 floors underground, and above there's going to be a reinforced concrete ceiling because there's going to be garages(very rarely used), so i'm going to have quite a bit of mass overhead, and around...
anyone care to give me a definite answer and stop me wondering"what if"??????

thanks

Bob

[knightfly]

Wow, join the club with the rest of us who only want perfection on a low budget :=)

Seriously, we would need to know what you mean by "not a lot" in the budget, as well as a rough idea of what building materials cost in your area. It would also help to quantify what you mean by "no leakage", as every construction has a finite amount of leakage and whether it's too much depends on several factors.

Can you tell us your approximate budget, what (useful) materials you have available to you, what they cost, how many rooms you need and what they will be used for, how loud /what type the music typically is that you will be recording (an inexpensive Radio Shack Sound Level Meter will help here) and whether you've considered HVAC (air handling, heat, cooling), whether you've settled on preferred ceiling heights, ways of running wiring between rooms, and ANYTHING else you think might be pertinent?

As to using hollow concrete blocks for room walls, I wouldn't do that. If you check the STC chart here (sorry, it doesn't cover MTC so low freq performance isn't very predictable)

http://www.saecollege.de/reference_mate ... 0Chart.htm

You'll notice that even an 8" thick hollow concrete block wall isn't as good as (say) a double-framed, steel stud gypboard wall which is lighter and easier to get straight than blocks, unless you're an accomplished masonry guy.

There are several ways of doing ceilings, some of which are resting a frame on walls isolated with absorbent pads, suspending the ceiling and frame INSIDE the room walls using dual element isolators, and several others depending on how the rest of the building is done and the degree of isolation needed.

Let us know some more details, and we should be able to come up with a usable plan... Steve

[Eric_Desart]

Hello Steve,

I always find those things difficult, possible looking as (not intended) lack of respect.

I can only repeat that STC comparison can give a false impression.
One can easily have increasing STC while simultaniously the music transmission loss diminishes.
E.g. When you have a brick wall and you add a resilient gypsumboard layer in front of it at ca 1.5". Your STC will significantly increase, but the overal transmission loss for studio like music will diminish.
Add an additional second layer to the other side of the brick wall and STC will rize further but music transmission loss will also decrease further. Note: in this case the typical triple leave system effect is relative insignificant due to the dominant heavy center leave (brick wall).
Add the two resilient skin leaves on the same side of the brick wall, than you have a real triple leaf system, creating a nonsense thing for both STC and Music.

So it's not only a matter of STC showing too high values (if so the relative comparison should remain correct). The problem is that the overall transmission loss for music is mainly defined by the mass-spring resonance (dip in insulation in low frequencies for double leaf systems) which single leaf walls doesn't have. As such a single leaf wall (as bricks) can prove much better, while showing lower STC.

This problem caused MTC to be developed (which never became official standard in US), and was also the reason for designing OITC (which is official US ASTM standard) to cover for those lower frequency effects significantly ignored by STC (and European ISO Rw for that matter).

At the moment lot is going in USA and ASTM, to look for adjustment, extension, an additional new, or substitute for STC, knowing that's bad for music, and any kind of trafic noise.

In fact in US the OITC is the best currently official ASTM standard to expess music transmission loss. Problem is that it is based on a frequency range from 80 Hz to 4000 Hz (unlike STC covering 125 Hz to 4000 Hz). There is still little 80 Hz data available, but one could calculate OITC on 100 to 4000 Hz too.
Only drywall producers (not forced by official rules) won't publish those since the difference with standard STC looks terrible.
It's the power of this STC value, that also emphasis the positive effect of RC, which for music noise isn't that obvious at all.
I'm also rather convinced that's the power of STC, which direct Research & Development efforts, which for me is at the expense of improving walls for every day use.

One should note that the European Rw and US STC are designed very long time ago, when logarithmic calculations were time consuming and not for everyone. STC and Rw were designed when radio broadcasting and equipment were limited (as matter of spreech) to the mid frequency range. So disturbing noises were defined by traditional house hold noises and voices.
In fact the STC and RW weightings are based on the averaged stylized behavior of SINGLE leaf brick walls.

Double window producers however will use it since OITC is designed for OUT IN (traffic: air, train road) noise (should loose credibility if they shouldn't).

Certainly when comparing single with double leaf systems an STC sort order (even relative) can deviate a lot from a music sort order.

If we should use Rw (European version of STC) for calculation of discos or Horeca or comparable in function of environmental or neighbor disturbance regulations, it's possible that we loose accreditation. Such a study should automatically be labeled as invalid, and the study office as questionable.

Kind regards
Eric

[knightfly]

Thanks for that, Eric - I've not been able to find much info on anything BUT the STC values of walls, and it's been very frustrating. Anything you can contribute toward needed wall design differences will be much appreciated here; I'm aware, and I hope others visiting have become aware, that STC isn't the final answer. I've probably not made a big enough deal about that, only mentioning it from time to time.

It's too bad that so many things are "dollar driven" in the world - since so many more people live in houses than build recording studios, we seem to be stuck with sub-standard rating systems at the moment.

I'm hoping that changes, because I'd really like to know what kind of walls I need in order to stop that low "B" string on my new 6-string fretless :=)

Even though my lack of formal engineering education sometimes limits my understanding of parts of your contributions, I ALWAYS welcome the challenge they (usually) present, and appreciate your input very much.

I hope to finish the drawings that are necessary to ask you a series of questions along this line, relative to my own planned studio build - I've been looking at Insulated Concrete Form construction, and wondering what the 2.75" of closed-cell foam on the inside will do to my goal of improving MTC. More on that later though - thanks again for your valuable inputs... Steve

[AndrewMc]

That BBC report mentioned in the other thread
http://www.bbc.co.uk/rd/pubs/reports/1995-06.pdf

Is about the most informative (& understandable) analysis of Transmission Loss vs Frequency that I've come across - detailing many different wall designs. No mention of STC by the BBC ( I don't understand what STC even means beyond it's some kind of average across the frequency range - how is STC calculated?)

[Eric_Desart]

Look at:

http://www.acoustics-noise.com/Diverse/ ... -dBA.shtml

On top of the page is a link to a Word document explaining how STC, MTC and OITC are calculated.

Eric

[robertbonello]

ello

thanks for the replies, though i must admit... i've just spent a couple of hours reading a bit too much about acoustic research for this time of night...

no but seriously... erm, where to begin...
soooooo, as regards materials, i've actually got a contact who can provide most stuff at cost price, so i'm expecting much of my raw material cost to be significantly reduced, which is nice...
i live in malta, which is a tiny little island, which means that some stuff is obviously going to be a bit tougher to get hold of, and costs would be higher than if the materials were readily available.

in terms of what i'm planning, i'm going to have a pretty tight budget for what i have in mind. i'm hoping to have something in the region of $10,000 to spend on the actual construction...
with that i hope to be able to have a comfortable control room (something like 20x17 feet), a vocal booth, stone drum well and a live room - the bigger the better. i think i'm going to limit the ceiling of the building (i.e the concrete of the house itself) to something like 14 feet, so i'll obviously be limited by that for size of the main live room. those are the rooms that need the isolation, other than that i've got the rest of the complex(machine room, bathroom, pool room etc...) but i don't really need to consider those for now(the building begins october, i won't begin work till christmas probably).

Once i'm going to have lots of concrete work going on building the actual house, once the whole floor(second basement) is finished, i'm going to get them to float the floors of the various rooms(i.e. isolated, treated rooms) separately, complete with ducts for wiring hopefully. then the rest of the building can go up, and i should have myself four slabs of concrete floated on pads or springs. once i have that, i can look to construct the rooms however makes the most sense. if it makes most sense to build up wooden frames and then the various studded, multilayered walls and ceiling off that then i'll do that, what i was wondering was whether it would make most sense to build up the various rooms out of concrete(so that when you walk into the basement once this is done you'd find four built up rooms, with gaps between them) and then build my separate non-masonary) walls inside those. my guess being that it would probably be a lot easier to work that way, and an extra layer of hollow concrete brick would do wonders to an already decently acoustically insulated wall.

the physics of actually building a four room studio essentially out of timber would be a much harder job for me to pull off(with professional help when i need it obviously) than the isolation and treatment of four separate rooms. remember to my budget i have to consider stuff like doors and windows and all the other stuff, but concrete walls would be done relatively cheaply and by the people building the rest of the house. it's actually two semi-detached houses, with a floor of basement each, so the space i have to work with is pretty big, an extra 2 or 4 feet is not going to cause me major problems.

i am definitely going to require an hvac system, though i haven't got a clue as to what's available, or how much it's going to cost... i've still got a loooooooot of planning to do, but could someone point me in the right direction for that please?

as to how much isolation i'm looking at, i'm definitely a night person, and my favourite (and most productive) time for working (on my own material - clients look at me funny when i try to book those times) is actually between 2 in the morning until about sunrise, which is the worst time possible for making noise. what i'm looking at must satisfy two criterion. the first is that a 4*12 turned up to eleven, a loud drumkit or a pumping bassline do not leak between the various studio rooms(at least not enough to effect a delicate vocal in the dead room for example)The second is that the noise does not leak to the rest of the house, or the neighbours next door. i'm not looking at death metal noise, but even good ol' rock n roll can get pretty noisy.
still being vague, i'll say that i need the rooms to be [i]quiet enough[/i]. i don't need absolute silence, but i want to hear next to nothing if i'm standing next door to someone going mad on a drumkit. the idea being that i try to track live with creative music, and your first take is often your best, so i wouldn't like to have to redo the vocal because of leakage from the other instruments for example. i know i'm asking for a hell of a lot, but i reckon that with a good six months of serious planning(my closest friends are an architect, an interior designer, and a phsyics professor in the making, so i should be able to get me some help with those difficult words), and the amount of time i'm expecting the project to take (i'm reckoning it's going to be bloody hard work, and i'm figuring that it might even take me a year before i can move the equipment in), and the fact that i've got some pretty skilled professionals on hand (albeit ones with no studio construction experience), i figure that i should be able to do what i want.

i figure if you guys can do it in something like a month max. i reckon i should be able to do something decent in a year, without too many cockups hopefully(with all you gentlemen's gracious help of course).

k, i think that's answered most of the questions... i think you should get the idea of what i've got in mind. if i'm looking at something which is going to be too difficult, expensive or complicated to pull off then please let me know, though i reckon with enough time i should be able to do it... hopefully of course

your help is seriously appreciated, and though it's a while off i'd rather be 100% sure how i'm going to be working by the time the builders get the plans of the house.

and one last thing... is it all that hard to actually build a studio after all?

[knightfly]

Robert, first off - if you're doing a control room that's 17 x 20, with a 14' ceiling, it's hard to get a better modal distribution than that.

Next, considering the degree of isolation you want you may indeed be better off having the main walls of your rooms built in concrete. However, doing that using HOLLOW concrete block isn't going to get you as good isolation (except possibly at lowest frequencies) as multi-layer, double leaf gypsum wallboard framed with steel studs.

I've not done much with concrete, and even less when sound proofing was a criteria so I'll probably be of little assistance in that area - keep in mind, though, that floating floors/rooms need to be specifically designed for the particular loading or they don't work right. You need to take into consideration the percentage of compression at WORKING weight, which will involve spacing of the supports, weight of EVERYTHING on those supports, etc -

Here is one company that specializes in such things; even though they probably don't have a rep in Malta, they may be willing/able to help you with details and hardware via emails, etc -

http://www.kineticsnoise.com/architectural/index.html

As to doors and windows, while it would be nice to just call Overly Door and order what you need, the doors alone would more than eat your entire budget. As an alternative, there are ways of using exterior doors in combination with a sound lock (vestibule) that can get you decent isolation for about 20% of the cost of pro studio doors - windows are another story, and would involve some calculations to achieve similar mass to the walls they are mounted in.

HVAC for studios can get as expensive as professional doors, but if you know the main requirements and have someone who can implement them you can do pretty well.

The main things to watch for are -

1. No two rooms served by the same duct (run ducts all the way from HVAC unit to EACH INDIVIDUAL room, same with returns)

2. HVAC unit isolated from structure, including flex duct attachment to sends/returns

3. Relatively long runs with 2-3 bends, both supply and return, absorbent at corners, supply and return pressures properly equalized

4. Larger than normal fan, with SLOW mode, preferably NOT axial fan - "squirrel-cage" types are typically quieter, plus noise from moving air is roughly related to at least 4th or 5th root of velocity, so a small reduction in velocity helps reduce noise a LOT

5. Larger than normal cross-sectional area of all duct work - in a round duct, 1.414 x diameter = twice the area, = HALF the velocity for the same amount of air, which means a big noise reduction.

6. If you try to adapt a "normal" HVAC unit to studio use, you will probably run into problems such as freezing up due to lower than designed air velocities - I've not done any HVAC personally, but have heard of this being a problem. Perhaps one way around that, would be to use a quality home HVAC unit but enlarge the ductwork before it gets to the studio rooms - this would slow the air velocity, but keep the air handler at its design point. If there is a specific frequency of noise involved, you could probably build a tuned trap plenum between the studio and the HVAC. There you have the sum total of my HVAC knowledge as applied to studio building... :=)

"is it all that hard to actually build a studio after all? " - It's not the building that's hard (just tedious and somewhat expensive) it's the knowing what, where, when, how, if, etc that can get more than a little daunting... Steve

[mpr3]

Steve, thanks for that information regarding the HVAC. I have a few follow up questions.

1. I have read here that using MDF boxes with interior insulation make for great ducts, but in my situation (3 rooms, 6 ducts total) that would be very difficult to pull off. What is the easiest way to get send and return ducts into these tightly spaced rooms? Isn't there some flexible tube duct with insulation on the inside?

2. What do you think about using outtake fans to help pull the air out of the studio rooms and bring in the cool air from the intake ducts? I am hoping that I could use three large outtake fans mounted on the outer wall (away from the rooms), each with a variable speed control to help regulate airflow. Since I am considering using 1 or 2 larger airconditioning units to supply air for all three spaces, if I wasnt using the overdub room I would turn that rooms outtake fan off and to keep air flowing into the active spaces. Could this work?

Here is a link to my posted floor plan:
http://johnlsayers.com/phpBB2/viewtopic.php?t=378

Thanks again!

[knightfly]

Mark, I should have been in bed two hours ago so this will need to be fairly brief - first, there are round flex ducts available that are reportedly very quiet, here's a thread where they're mentioned -

http://www.recording.org/ubb/ultimatebb ... 4;t=000466

As to the exhaust fan approach, that could get pretty tricky. Here's why; any time you use "real" air conditioners (as in one unit for several rooms, complete with duct-work) there is a fine balancing act that needs to be done - I've not done any of this, but have read some of the details.

Basically, you need to adjust the air intake to equal the air outgo, by using dampers in ducts to achieve a balance. If this isn't done, you end up with either a positive or a negative pressure in the room, as compared to atmospheric pressure. This can cause quite a bit of noise in a studio, due to the uneven pressure needing a place to equalize. Usually, this happens by causing air leaks around door seals, which if more than about 1/20 of a pound difference will be audible.

At the risk of sounding like a cop-out, HVAC is one area you may need to spend some money on to get it right. It's just not possible for someone to guide you through this from 3000 miles away and expect you to be happy with the results. A professional will have the sensitive pressure gauges that can balance these sends/returns so they don't cause extra noise, as well as balance the static pressures in the whole system so the AC survives.

It will be money well spent, especially in a warm humid climate like Hawaii. I lived there for about a year and a half, and I don't remember another time when I changed guitar strings so often (rust, sweat, more rust...)

I hope that wasn't too dis-appointing, I know I need to learn a lot more about HVAC myself; I intend to do that, but it may take a while to find the time... Steve

[mpr3]

Steve, thanks for the heads up about that tube duct. I think you are right about this AC thing. I need to spend more money than I had originally planned to get it right. If things get too hot and nasty inside that would dramatically affect the performance of both the talent and the engineers. If I didnt have a split-system in my home I probably would have moved to Vermont by now.

[knightfly]

Mark, another possible useful idea for your setup would be to get a fairly hefty de-humidifier, and run that whenever you're NOT using the studio - Hawaii's humidity was what made it less than perfect for me, the actual temperature really wasn't that bad.

I have a small (de-humidifier) unit I use in my 500 square foot one-room studio at present, and it extracts so much water that I had to plumb in a drain instead of just emptying the catch basin - that room has to get several degrees warmer with the lower humidity before it gets uncomfortable to be in.

If you can keep the humidity down in off-hours, not only will your AC unit have to work less to make things comfy but any acoustic instruments stored there will thank you.

Another plus - with lower humidity, you shouldn't have to set the AC thermostat so low, and customers will experience less "freezer burn" when coming and going back to normal climate... Steve