Practice Studio Construction

Some Colleagues and I am in the planning stages for converting a warehouse building into 10 practice studios. I have been browsing the forum to try and decide what construction methods we should use and what level of soundproofing we need. I assume we dont need so much as for sound recording but how much do we need ? They are to be comercialy rented out on an hourly basis. I see that the norm for recording setups seems to be triple thikness of wallboard each side of an airgap + rockwool - Will we need the same ? If we decide on block construction what method should we use ? two block walls with a gap ? The building has solid concrete floors - will we need to do a second isolated floor ? Is there a formula for calculating contruction costs via each method ? Are there any special wiring considerations (apart from local legislation ?) Thanks for your help Is there a rule of thumb for calculating aproximate construction costs ?

Fred, welcome to the board; first, can you please edit your profile to include a location? This is a WORLD wide resource, and prices/availabilties vary WILDLY... Second, it doesn't sound as if you've read through much here http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2125 If you can read through at least the top 3 threads there, it should help with understanding quite a few of your questions; then, any "leftovers" can be handled here. Sorry for this, I'm just too far behind to continually "regurgitate", hope you understand... Steve

Hi, I've edited my profile and had another look at the construction threads. But I still don't feel able to decide which method I should use . I guess what I realy need to know is what STC rating we will need. Thanks for your help

Greetings, Fred... I'm by no means an expert around here (which means, if I write something that someone else disputes, believe the other guy! ;) ), but there are some questions I think I can answer, and more importantly, some questions I can ask you, that I think will be helpful in getting things moving along for you.

Fred Case wrote:

Some Colleagues and I am in the planning stages for converting a warehouse building into 10 practice studios.

Provide as many details as possible about the warehouse building -- a floor plan will be very helpful, including how you propose to lay out the individual studios. We'll need as much detail about how are the existing walls and ceiling are currently constructed.

I have been browsing the forum to try and decide what construction methods we should use and what level of soundproofing we need. I assume we dont need so much as for sound recording but how much do we need ? They are to be comercialy rented out on an hourly basis. I see that the norm for recording setups seems to be triple thikness of wallboard each side of an airgap + rockwool - Will we need the same ?

If not that exactly, probably something close to it. The "triple thickness of wallboard each side of an airgap" is the basic equation of the decoupled mass-air-mass (a.k.a. "m-a-m") construction technique. It is technically possible to achieve soundproofing by using mass alone, but it's much more efficient ($-wise and space-wise) to use the m-a-m model.

If we decide on block construction what method should we use ? two block walls with a gap ?

If you use a "two block walls" technique, it's important that the block walls be filled with sand so that each block wall is considered one "mass" in the equation. Otherwise, the air inside the block wall becomes "air" in the m-a-m equation, and it's not decoupled. In such a case, you'd actually have m-a-m-A-m-a-m, and that's very bad. In your reading of the Announcement threads, and perhaps in your research before posting, you probably learned how critical it is to obey the "two leaf" rule: it's the "sweet spot" in soundproofing.

The building has solid concrete floors - will we need to do a second isolated floor ?

My money is going on "yes," but this is a question best left to the experts. It probably also depends on what your needs are. There's also the question of your priorities for isolation -- how importat is it to you that sound not leak outside of the building? Much of this depends, I'm sure, of the bulding's surroundings, who your neighbors are or will be, zoning, what local noise ordinances are, etc. There are so many variables here, but as of yet, you haven't mentioned any of them yet.

Is there a formula for calculating contruction costs via each method ?

By "each method," do you mean block vs. frame & gypsum? The answer to that probably depends mostly on your location, as there are some parts of the world where gypsum is very expensive.

Are there any special wiring considerations (apart from local legislation ?)

I'm guessing that if the rehearsal rooms aren't going to be used for recording, there probably aren't too many "special wiring considerations," other than perhaps a lesser number of outlets on each circuit than is customary, just to prevent overloading with all those amplifiers drawing current.

Is there a rule of thumb for calculating aproximate construction costs ?

The biggest factor here is how much of the work you'll be doing yourself vs. hiring out. This is one of my most "clueless" areas. Perhaps after posting more details of your project, some of the "real" experts here can comment.

...I've edited my profile...

The edit didn't "take." It might be that you didn't click [Submit] when you were done. Therefore, we still don't know your location. Give it another try.

I guess what I realy need to know is what STC rating we will need.

Focusing on STC ratings was one of my missteps in starting my own project... Fortunately, I was "set straight" early on: I have since learned that STC, while it does give a "hint" as to the effectiveness of a soundproofing method, is only a relative number as it regards the speech range of sound. In other words, if you were constructing condominiums or offices, where speech privacy is the consideration, STC is a good yardstick to use. However, for music studios, especially where acoustic drums and amplified instruments are concerned, the sound generated is an "assault" across several octaves, way beyond what mere STC measures. The hardest sound to "kill" is low end. (Think about how "boom cars" can be heard hundreds of yards away.) Killing low end requires more mass, and a wider air gap. There are theoretical formulas for this, but I'm not as well versed in them. For a great overview of these concepts, see Custom Audio Designs' Soundproofing Basics and Transmission Loss in Panels. Pay particular attention to Figure 6 in the latter -- the graph depicts how there is less Transmision Loss (TL) on the low end. (High TL = good.) We look forwarding to hearing more from you... And remember, the quality of the information you receive is proprtional to the quality of the information about your project that you post. :)

Hi and thanks for the reply,I'd already browsed some of your posts before. I've reupdated my profile now so as you can see I'm in Spain. I'm sorry that my posts may seem a bit vauge but its because we are in the early planning stages. Trying to get as much information together in order to prepare a buisness plan - as I said the idea is to do this as a comercial venture. Because of this I can't yet be specific about the building or layout. We are currently looking for a building located in the "industrial areas" of the city. ( I should have said " IF the building has solid concrete floors.....") Hoping for a 300 to 400 m2 probably warehouse or textile factory building which will need to be near to a metro station . This is very important and we are expecting to have to spend a few months looking for the right property.Time we can use to suss out the best way to do things. We expect to pay contractors to do the building work. But I am trying to get a clear idea of what we will have to specify - both for budgeting the project and to get it right first time. Basicaly the idea is for 10 rooms of 5m(l) x 4m(w) x2.5m(h) As a starting point . Going on the idea of 3 thicknesses of wallboard each side of an airgap I calculated 1950 m2 in total ( not allowing for wastage or a hallway/ office /toilets ) wallboard here costs €11,98 + tax (16%) per sheet this gives a total of 12423 € on wallboards alone.(inc. tax) without taking into account labour/wastage /joists / rockwool /plastering over. At this point I noticed that another forum member is also located in Spain (Hugo Inside) and has started building so I asked him what costs he had found. He was kind enough to inform me that he had been quoted wallboard + metal structure + rockwall + labour €22 / m2 (+tax) or blocks + labour + cement €35 /m2 (+tax) To my uninformed eye it looks like the blocks might be best since the wallboard needs to be triple thickness then plastered over and finaly painted. wheras the blocks need to be filled with sand then painted. I hope that this additional information is usefull and look foward to seeing your replies /advice. With your experience what route would you go down ? Thanks :D

Great info, Fred... I think that may be enough to get some juices flowing around here. :) FYI, one thing:

You wrote:

...the wallboard needs to be triple thickness then plastered over...

You might be able to skip the "plastering over" part and just paint the wallboard directly. (Of course you'll still need to "mud the joints.") Good luck! And hopefully some of those "experts" can now chime in with their ideas/questions.

All good info so far; I would add that one reason for better low frequency isolation in this case is CONFUSION - By that, I mean - have you ever tried to play in tempo with a group when ANOTHER room had a boom-box or stereo going, and gotten confused when you tried to stay on the beat? This can be a real downer with adjacent practice rooms, sometimes even studios. I remember one recording session in Portland Oregon when we actually had to STOP recording and wait for the UN-F'ing Believably LOUD Metal band in the OTHER, "B", studio to finish a take - just enough LF rumble to throw off our meter and concentration (we made the studio knock off some time, not our fault they weren't as soundproof as they needed to be) For that reason, if you want your practice rooms FULL most of the time I'd go for floated floors and NO FLANKING PATHS. Whichever method you use, pay more attention to TL at 50 hZ than you do STC - if you design for the lows, the rest will be no problem. Human hearing threshold @ 50 hZ is about 55 dB, so if you float masonry floors (or contained dry sand, if it's cheaper) with a fairly deep INSULATED space below, you should get good enough isolation for drums to become barely audible at a band SPL of around 100 dB or so. This is just a rough ballpark figure, even perfectionists can't build the same wall twice and get the exact same isolation... Ceilng and doors will be harder to get right than the walls, in general... Steve

Hi Thanks for that reply. So for the floating floor should I go for something like the left hand part of Fig 5 in the document "Controlling the Transmission of Impact Sound through Floors " ? Am I right in thinking that I will need to construct the walls on top of the flotaing floors. Or can I build the walls first and then do the floors as shown in figure 5. Also I have found a supplier of acousticaly insulated doors with frames. They have a range of doors with different levels of sound attenuation what level do I need - they have doors rated at 33,37,41,42,44 and 53 dB Thanks for your help

So for the floating floor should I go for something like the left hand part of Fig 5 in the document "Controlling the Transmission of Impact Sound through Floors " ? This is the general idea, but Impact noise is higher frequency than bass or drums; for that, you would need a deeper air gap and higher mass floated floor. Check out Sharward's thread for an effective isolation system for drums, specifically the amount of mass and air space in his floor. Am I right in thinking that I will need to construct the walls on top of the floating floors. Or can I build the walls first and then do the floors as shown in figure 5. This gets trickier the more rooms you have "attached" to each other - you either violate the "2-leaf only" rule or you suffer from flanking noise - see my questions at the end of this post. Also I have found a supplier of acousticaly insulated doors with frames. They have a range of doors with different levels of sound attenuation what level do I need - they have doors rated at 33,37,41,42,44 and 53 dB Have you priced these? I'm curious what they want for a "53 dB" door. There may be cheaper alternatives locally, but you'll need to do some checking around. I've done a VERY basic sketch of best isolation for multiple sound booths in a row - these would be easier built using 100mm SOLID brick, but any TIES between the courses would HAVE to be resilient, like shock absorbers of some type - I have no clue what's available in your area so you will have to do the research and ask about the suitability of whatever you find. Note that the doors are all in the same area of their respective room's wall - this is no accident, it keeps the door near an intersecting wall for good hinge strength, and it keeps the NEXT room's door away from it for best isolation due to leakage around door seals; it also keeps the floor plan for each room identical, so you can mass produce whatever acoustic treatments you use inside without having to recalculate modes, etc, for each room... Steve

Hi , This is just a quick post to say thanks for that information. Unfortunately I'm snowed under with work at the moment so I'm having to put things on hold for a couple of weeks. If youre interested in the specs of the different doors heres the link (unfortunately they havent got back to me with prices yet) http://www.acusticaintegral.com/index1.htm Thanks again