Planning design of a full recording studio/ Now building...

Ha that's the word for it, so simple. You don't want to know how we call that in french !

Well that's presuming allot :lol: come on provide us with kicks and giggles. Can always use "code language" if it's to vulgar. 8) Marc

orangenumerik wrote:

Thanks to Sharward for the span calculator this is exacly what i was looking for. Maybe you can help me with that , what is the deflection limit factor in the calculator. and i am also not sure about the live and dead load thing.

Read Understanding Loads and Using Span Tables by Paul Fisette on the American Wood Council Web site (the same site that hosts the span calculator). --Keith :mrgreen:

Sharward

Read Understanding Loads and Using Span Tables by Paul Fisette on the American Wood Council Web site (the same site that hosts the span calculator).

Thanks. I'll check that today. guitardad

Well that's presuming allot come on provide us with kicks and giggles. Can always use "code language" if it's to vulgar.

Well there is nothing vulgar about it it's just that the english word make more sens to me. The french word for it is " Étrier" wich means in a 1:1 translation "stirrup" ,:shock: you know that thing in wich we put our feet in when we go horse ridding So picture this " My 2X8 joist will be holding on the wall using 2 stirrups at each end"... :lol: ... and the possible answer : why are you using horse saddle in your ceiling construction ? i though you were building a CR not a barn...:lol:

Ok, here’s the latest development. After some work with the joist span calculator and with a talk with one of my friend who is a house builder. The graph below is what we came up with. All 2X4 were replace by 2X6, thanks to guitardad. The big central joist is now two 2X10 glue and nailed together. The front joist use the same technique but with 2X8. I won’t use joist hangers as I was planning to do. Instead, I will nail two 2X4 togheter that will serve as support for the joist then i will cut a hole in the wall so that the joist is not touching the gypsum boards and nailed them to the 2X4 support. This part is still a work in progress though, it may differ slightly from what we see in the graph below. The numbers : Total square footage 199 f/s Approx. weight for : fourteen sheets of 5/8 type X gypsum boards : 980lbs eighteen 2X6X10’ : 293lbs four 2X8X10’ : 100lbs two 2X10X16’ :120 lbs 2.2 pack of 3” rockwool : approx 100lbs RC channels : unknown estimated 50lbs Total : 1643lbs If I got this straight the dead load for this ceiling would be 513lbs (weight of the frame structure), 2.57lbs/sf And the live load would be (weight of the RC channels+rockwool+Gypsum boards) 1130lbs, 5.68lbs/sf. So what do you guys think ? Thanks

I am not there yet but I have to make it happen so here’s some questions regarding my future rear corner hanger bass trap. I have enough room in that corner to have it 4’ deep, is it too much ? my understanding is that as far as basstrapping is concern it is never too much , but maybe someone has another point of view. I have read a lot about hanger bass trapping on this forum and some books,and I know there is no data as to how they actually work but but there seem to be some confusion around the way the hangers should be placed inside the trap. Some say one hanger every 8”, other say to place those hanger so the insulation of each one barely touches the next one, or to place them in a heringbone patern. Is just a matter of personal belief ? or trial and error ? no pun intended really. What would work best. ? Am i better of with a “superchuck” kinda bass trap? Below is a graph of what I am thinking of . Mainly built with 2X3 and not touching the walls and the yet to be built ceiling. The largest panel would be 9’ high by +/-3.5’ deep. All cavities inside the trap would be filled with 3” rockwool but the insulation on the panel themselves would be 3”standard fiberglass. The reason why the front corners of the trap are “cut” is because there will be some high freq absorbers on those walls see CR graph below. There will of course be a fabric to cover it all. Thanks to all.

Reread definition of live load and dead load. All loads you described are dead loads.

If I got this straight the dead load for this ceiling would be 513lbs (weight of the frame structure), 2.57lbs/sf And the live load would be (weight of the RC channels+rockwool+Gypsum boards) 1130lbs, 5.68lbs/sf. So what do you guys think ?

As long as your numbers safely add up GREAT! Clarification, as I understand it: Dead Load= weight of all building materials in structure including RC channels+rockwool+Gypsum boards Live Load = People, furniture, cabinets, Uncle Bob... things that would be on a floor of a room that are not permanent. Live load doesn't really apply to a inner leaf ceiling except maybe the weight of acoustics like a cloud hanging from it... but really that would be dead load too. However even a roof has a live load rating because occasionally it does get walked on. As to your bass trap question, I want to read somebody else's answer as I've not been able to make my own decision for my room on that either. BUT your right on "as far as basstrapping is concern it is never too much " the smaller the room the more bass trap you can afford the better. The Slot resonator on your side walls... I've read many times how difficult it is to build one of those to the correct frequency of the room. It appears your not going with a variable depth and frequency slot resonator, which will limit usefulness. I did a lot of research months ago on the slot resonator, currently there dropped from my plan. I would love to find a reason to put them back in as I like the look. Now you need to confirm this for yourself BUT I do not think in your "as is plan" there going to help a lot. One thing to keep in mind is that you can only take an educated guess what frequencies will be bad in the room until you actually have it built and test it, other variables can bring in unexpected bad frequencies... then you can build the acoustics (maybe slot resonator) for those frequencies. Marc

Great live load vs. dead load definitions, Marc. 8)

guitardad

Dead Load= weight of all building materials in structure including RC channels+rockwool+Gypsum boards Live Load = People, furniture, cabinets, Uncle Bob...

Ok i got it now. So i only have a dead load and it is of 8.25lbs/psf But what if Uncle Bob is dead ? :wink: Well it obviously doesn't show on my plan but your right the resonator would have a variable air space, 3"1/2 bottom to 8" top, otherwise they have a very narow freq. range. as you pointed out. Don't get me wrong though. I am not going to build the resonator before room analysis. I have a life beside that studio thing you know... :wink: I have just put them in my plan only because i suppose i may need them. And because they look soooo cool 8). But i am to build all corner bass traps from the start though, cause as you pointed out, this is where low freq. modal activities are worst in any small room. I would need some clarification about bass traps calculation. First let's just say that i know that these are broadband bass absorber. But that being said. I have read somewhere that in order to reduce a given frequency the depth of the trap must have at least 1/4 the depth of the wavelenght of that given frequency. So a 4' deep bass trap (like mine) would only be effective down to around 69hz, 69hz being 1/4 the wavelenght of 277hz wich is 4' long, seems a little disapointing to me. In Rod's book there is an "how to" for a corner slat bass trap with an air space of only 1'7" and he says that this panel will handel freq. ranging from 66hz to 155hz. I don't get it , obviously i got something wrong :oops: Marc if you find your answer as to wich technique you are going to use in your bass trap let me know. I'll do the same. Enormous thanks to you guys.

But what if Uncle Bob is dead ?

Well, if Uncle Bob is dead and still in the room let's nail him down, seal perimeter with acoustic caulk, fill cavity(s) with Rock wool to avoid triple leaf OR even try and make a bass trap out of him. :twisted:

Marc if you find your answer as to which technique you are going to use in your bass trap let me know. I'll do the same.

Well, I'll working with more of a rectangle room then you so I'll have 2 bass traps in rear corners of my room OR something like that. Will also have traps on wall ceiling corners. Dimension of single my room are about 9' x 15', splay or no splay? slot resonator? exact acoustic treatment???? Don't know yet. Isolation is important to me, so that will effect my end decisions on acoustics. Currently I'm not thinking about acoustics, I'm sure you can understand how I feel over whelmed with the options. I've considered a lot of acoustic treatments and building techniques, my last plan is way simpler then where I started. I think it comes down to looking at all the options of proven techniques, play an elimination game of what you need and are capable of building. You might get to your bass trap answer before I find mine (for a different shape room). Marc

OH yeah... where are you planing to put the RC? On the inner leaf of ceiling and/or walls that are decoupled from the outer leafs of walls/ceilings.... or are you inner leafs somehow coupled or part of outer leaf? Marc

Hi Marc

Well, if Uncle Bob is dead and still in the room let's nail him down, seal perimeter with acoustic caulk, fill cavity(s) with Rock wool to avoid triple leaf OR even try and make a bass trap out of him.

I wonder how is fat as sound absorber...?

splay or no splay?

I would defenitely go with splayed walls.

where are you planing to put the RC?

RC will run under the ceiling frame to support both layer of Gyspum board. No RC on Walls. These will be double partition walls.

On the inner leaf of ceiling and/or walls that are decoupled from the outer leafs of walls/ceilings.... or are you inner leafs somehow coupled or part of outer leaf?

I'll be honnest with you, not matter how i read the above paragraph, i just don't get it :oops: Can you clarify. BTW can you direct me to the link of your project, i'd really like to have a look at it.

Quote: On the inner leaf of ceiling and/or walls that are decoupled from the outer leafs of walls/ceilings.... or are you inner leafs somehow coupled or part of outer leaf? I'll be honnest with you, not matter how i read the above paragraph, i just don't get it Can you clarify

OK and more to the point. I'm wondering why you want to use RC under inner leaf ceiling frame to attach drywall to. IF you are building a true room in room (decoupled) with inner ceiling being supported by inner wall frames then using RC will not be of any isolation benifit. May as well attach the drywall directly to the inner ceiling leaf and add a little more height to room. I can't tell from this thread (unless I missed somtehing) if your planning for your inner ceiling leaf to be directly or partially attached (coupled) to you outer ceiling leaf (existing ceiling) OR outer wall frames which would warrant the use of RC. It does not appear that way, you mention at one point you do not want to add weight to existing ceiling. RC is only of isolation benifit when used in a single (coupled) frame wall or ceiling. I've seen this on many posts on this forum and it's in Rod's book I believe. Splay... yes I am going to... but exactly how I'll splay is still an internal debate for me. My thread is this one: Marc's Patio & Garage Studio I'll warn you, I can babble. Some of it may not seem like "studio talk" but to me it's all talk about getting to build my studio. Marc

Eric, it's about 3:30 am here and I'm about to drag my carcass off to bed, but I'll try to cover a couple of things - one, you're still confused about loading - dead load is ALL structural parts of the floor or ceiling - framing, paneling, insulation, everything that's ALWAYS there. Live load is things like people, furniture, appliances, pianos, etc - if you hang 2 layers of 5/8 wallboard that's about 4.8 PSF - 2x6 framing (necessary, as Mark pointed out) on 24" centers, weighs approx. 1.2 PSF - and 3" rockwool will add about 1 more PSF (assuming 3 PCF material) for a total of around 7 PSF. This means you need a dead load rating of 10 PSF, and doug fir 2x6's, #2 grade, 24" centers will span 10'4" - you have a bit of leeway here because you're UNDER 10 PSF, so this will meet span requirements. I'm also glad you're beefing up the center beam, since it will hold half the total weight of your ceiling. (The inner half of EACH half, approximately) Acoustically, whether you support your ceiling on ledger boards fastened to the walls or support it on TOP of the wall plates should make no difference. Structurally, I'd get a local engineer to look at what you want to do rather than take a chance on having the ceiling fall. Personally I'd NOT want to take the chance, although a 2x6 ledger board fastened to each and every stud with 16d nails (3 per stud) isn't going to go anywhere in this situation. Isolation-wise, the thing you do NOT want to do is tie any of this to your OUTER leaf mechanically... Steve

Guitardad

and more to the point. I'm wondering why you want to use RC under inner leaf ceiling frame to attach drywall to

Marc, you are right, I'm just seeing so much ceiling using RC in this forum that i've just forget their purpose, and blindly included them in my ceiling plan. i Just don't need them. Thanks. But (notice there is always a but...) Just for my own knowledge, wouldn't it be to some benifit to have RC in the ceiling eventhough it is a true room within a room design ? I seem to recall having read this, about a double partition walls, using RC on one of it's side. Knightfly

dead load is ALL structural parts of the floor or ceiling - framing, paneling, insulation, everything that's ALWAYS there. Live load is things like people, furniture, appliances, pianos, et

Thanks for the clarification.

Acoustically, whether you support your ceiling on ledger boards fastened to the walls or support it on TOP of the wall plates should make no difference.

At last ! i was really not sure about that one. But after re-reading this reply a couple of times. I’ve remembered why I was asking if there would an acoustic incidence of making the ceiling hold in place by attaching it to the walls. See all my walls were built so they are not touching each other, their outer leaf is not touching the next one, ceiling and floor. Wall frames are only “linked” by the floor so the only path for sound to transmit the next wall is the floor and air. So by attaching my ceiling to the walls with 2X6 in the rear portion of the CR am I under the impression that I am just “shorting” those two outer leaves , cause they would then become connected via the ceiling frame. Seems logic to me. Don’t get me wrong , i am not arguing, I’m just trying to understand. That is also why this whole ceiling thing seems so complicated to me. I am just trying to built it without touching the inner leave where possible. Otherwise I would just put a big central joist then run rafters from there to the 2X6 placed on every walls around the ceiling perimeter. So if I am to loose 1db of isolation by doing it like that and “shorting” everything out. I can live with that. And it will be much easier to built. Am i completely out again, and confused with this whole thing. ?

Structurally, I'd get a local engineer to look at what you want to do

Don't worry i'll be looking foward to get one.

although a 2x6 ledger board fastened to each and every stud with 16d nails (3 per stud) isn't going to go anywhere in this situation.

You mean that it isn't going to fall or that it's not a good idea to do that ? (language thing ...sorry :( ) Time for a 3hours mountain bike ride…. Thanks to all

I found a structural engineer, he's supposed to come by today :P . And Since Steve mention that there should be no probs. fastening the 2X6 ledger board directly to the walls, i think i am going to go with that solution for every section of the ceiling. (exept for the main central joist of course) And ask Mr the inspector about it. Unless he ran aways when looking at the plans :wink: , i should be fixed on this issue soon. So i can built the damn thing :twisted: So if someone here thinks there is still something to be re-worked on my plan, please speak now.

Ceiling question - inner ceiling can tie to inner walls, difference in isolation between this and no hard contact will be nearly immeasurable. Outer ceiling can tie to outer walls, same thing - no problem. Inner ceiling frame connected to BOTH inner and outer wall frames - BAD BOY!!! NO NO !!! All the above are assuming that these two walls and two ceilings are your inner and outer leaves for isolation. If your inner ceiling is a THIRD leaf, it will detract from isolation BUT will also work well as a large bass trap, if you VENT in several places around the EDGE of the false ceiling and FILL above the false ceiling with fluffy fiberglass insulation - if there is enough space, you could also put bass hangers up there but it would be more work. Slats - you can guess what your modal problems will be, but that's ALL it will be with that shape of control room - better to measure after it's up. Also, calculating these using the AVERAGE depth is really just an educated guess - in actuality, unless you put a DIVIDER between each and every slat so that each slat becomes its own separate helmholtz, such a trap will have a strong tendency to AVERAGE its depth due to cross-talk between slots - this means that the end result will NOT be as wide a frequency range as if you had used separate dividers between slats, but it should be pretty smooth so it won't cause "bumps" in the room's response. Another thing - been reading quite a bit of this http://www.moultonlabs.com/main/ specifically this one http://www.moultonlabs.com/more/nick_ba ... interview/ And I've decided that this premise is a lot of why John's rooms sound good with slats on the (splayed) side walls- keeps the immersion thing going but "pulls out" some of the low mids to reduce mud in the sound. I've since decided that if you want to absorb early reflection points (on side walls) you should make these absorbers REMOVABLE and do a lot of A/B testing... Steve

So the inspector came Thursday and he looked quite baffled by my project. 8) But beside the recommendation he gave, as to how my central joist was supported in the walls, everything was OK for the ceiling and the rest of the structure for that matter. The “new support” picture below is how he’s recommending to support the joist. Steve, everytime you answer questions I had, you just open a whole new realm of other questions. :wink: So much info in a single answer. Let me digest it a while and I’ll get back to you, btw The links you posted are really interesting.To make things as clear as possible here’s a photo taken inside the CR that shows what I’ve got now, and what I intend to do. Finally the “end up graph” (last pict) is the whole thing as it would end up (not to scale). Now I want to apologies, sometimes i really got the impression that I am just posting the same questions over and over again. It is becoming really frustrating for me of not being able to express clearly what I want to say, and I feel it may get on peoples nerves. :? I think, that difficulty for me, may leave the impression that I don’t have a clue of what I am doing or that I am just running in all directions and sucking info out of everyone without research. Wich is not the case. I already feel better now. Thanks to all

I don't see any real problems there, I'm assuming that the single layer of wallboard at trusses will be your outer leaf and the new inner ceiling will be the inner leaf? I'd thought you had both leaves of the ceiling already there, and that the new innermost ceiling was to be a "false" ceiling which could then be vented along perimeter and filled with fiberglass for more bass trapping. IF this is to be your inner leaf, then don't vent it. The steel outer roofing (third leaf) will have some negative effect on isolation, but probably not a lot. No way to compute this that I'm aware of, just be aware of it. I'd also thought you were going to slope this inner ceiling - that would have helped with flutter echo between floor and ceiling wherever there is NOT a "cloud". Also, when reading the Moulton articles keep in mind that he's referring to a RECTANGLE - your rear corner MUST be treated as you intend, or at least covered with solid material if not rockwool - this, because a square corner will reflect any sound (above 500 hZ or so) back out of the corner PARALLEL to the entry angle - so draw a line from each speaker to your rear corner, "reflect" it across the corner and back toward the other speaker, and you'll see the problem - MASSIVE amounts of phasing/cancellation wavefronts in close proximity to the mix position, which can only serve to drive you closer to the brink of madness... I think I'd use that rear corner as a good place to store a MASSIVE amount of mineral wool (like a super-mega-uber-chunk) - in other words, fill the entire thing. IF this will be cost prohibitive, then at least line the walls and across the face with minimum 4" RW, and fill the rest with unfaced loose fiberglass. HTH, gotta run... Steve

The steel outer roofing (third leaf) will have some negative effect on isolation, but probably not a lot. No way to compute this that I'm aware of, just be aware of it.

Exacly. As you can see the outer leaf is rather flimsy I admit, but as I previously said I don’t want to add more weight to the building ceiling. I saw the “third”leaf caused by the roof, but there is not much I can do about it. And since this attic space is far from being airtight and has a quite large irregular cubic space , I tought the third leaf effect would be very small.

I'd also thought you were going to slope this inner ceiling - that would have helped with flutter echo between floor and ceiling wherever there is NOT a "cloud".

Well that is still something i am thinking to do, but i just can’t decide about it. If i slant the inner ceiling then put a “cloud” ceiling underneath i will end up having the same space behind it all around. And be effective only in a somewhat narrow freq.range. See graphs below. But as you pointed out, with a straight ceiling any aera not covered by a cloud ceiling will/can become problematic. On the other hand having the inner ceiling slanted also put it out of parrallel with the outer ceiling, wich i think can be some benefit to stop possible low freq. “resonances” between those two surface. Below are the 3 ceiling I am thinking of. V5 being the easiest to build. V3 being somewhat pointless, but gives me a couple of inches in the middle, i am just brainstorming... what do you guys think ?

...because a square corner will reflect any sound (above 500 hZ or so) back out of the corner PARALLEL to the entry angle - so draw a line from each speaker to your rear corner, "reflect" it across the corner and back toward the other speaker, and you'll see the problem - MASSIVE amounts of phasing/cancellation wavefronts in close proximity to the mix position, which can only serve to drive you closer to the brink of madness...

I did a listening test a couples of weeks ago, just using my ears, and you’re describing pretty much what is happening in the room. To put it short it really sounds like crap :lol: . At the listening point i had NO bass, but in the rear corner i had “earthquake level” bass built up. Still in the listening position, lots of 250-500hz, a dip around 1K and little too much around 5K-6K, very poor imaging. I didn’t recongnise my monitors anymore. But good news, beside that rear corner there was no place, when walking around the room, where i could hear a huge build up. I wasn’t expecting it to sound great really but that was bad ! :shock: I understand my room is all but square shaped. If you saw my previous plans, i could use up to 4’ deep by 8’ wide in that corner, and built a superincrediblymonstruouschunk kinda bass trap. So you think the superchunk is the best way to go in my situation, what makes you prefer the superchunk instead of hangers in this situation ?

Below are the 3 ceiling I am thinking of. V5 being the easiest to build. V3 being somewhat pointless, but gives me a couple of inches in the middle, i am just brainstorming... what do you guys think ?

With V3 and V4 you have the rear room ceiling angled down/splayed. I do not think this is a good idea. It decreases the available area for rear bass trap/absorber, for bass trapping back there the bigger the better. This decreases over all cubic feet of room making the room modes harder to deal with. The general recommendation when dealing with small rooms is to kind of forget about ideal dimension ratios, and make the room as big as you can. Angling the ceiling in front of room away from listening position as you show in V3 is a much better idea, as it helps kill flutter echo. Most CR's I've looked at get bigger towards the back, like a properly designed theatre. This makes sense to me. How ever if it were me I would build V5, regular level ceiling and add clouds with or with out hangers under false ceiling/cloud, and I think others would agree. Why? - Reflections between ceiling and floor are not as important as between side walls. - Cloud absorber will kill those reflections. - Level ceiling will be much easier to build. Figuring out all the (multi)angle cuts in combo with speaker soffits and splayed side walls & rear walls will be a small math project in itself. Then you have to actually make the cuts. - You could put some varied size hangers above your cloud, you could get a bunch up there. - It seems a cloud by itself rather then angling the ceiling should have just as good an affect if not better on room acoustics. I'm going to guess you've already looked at: http://www.johnlsayers.com/Studio/index.htm Previously and once I get in design mode again... IF I am optioning acoustic treatments for my room I go through all studio's on that page and look to see what they did... sometimes even taking score on how many did what I'm thinking about doing. Marc

Thanks for your input Marc, it is always appreciated. Below is the last (hopefully) and definitive plan of the ceiling V6. This plan is based on the V5 plan previously made exept the the ceiling is a little higher. I am aware that reducing the air space between the two leave would compromise some of the isolation but on the other hand it give me a slightly bigger room volume, 1813cubic ft instead of 1762cft. The space between the two leaves would only be 6” and I would completely fill that space with Fiberglass.

I would do at least a 1:10 sloped HARD inner ceiling up to the cross-beam, leaving ceiling height at full behind the beam; that will spread out modal stuff a bit in the front half of the room, and make it so you don't HAVE to use absorbent over your entire ceiling - this will leave you the option of tuning the room a bit more to taste, instead of having no choice but deaden it with full ceiling absorption to kill flutter. Same with side walls - get the ceiling up (insulation above it, of course), do the chunk in the rear corner (I think this will present a smoother response than arbitrary hangers in this case) and then LISTEN. TEST. See what your RT60 is. Listen some more. THEN you have the OPTION of adding more absorbent, instead of HAVING to just to "keep the rainbarrel away" (flutter) The other option would be to build your inner leaf parallel as you've shown, then frame ANOTHER, inner, sloped hard ceiling to accomplish the stuff in the preceding paragraph; this "false" innermost ceiling could then be vented around the perimeter and filled with insulation, adding more bass trapping WITHOUT taking all the "shimmer" out of the room... Steve (Now, how's THAT for raising more questions than I answer??!? :wink: )

would do at least a 1:10 sloped HARD inner ceiling up to the cross-beam, leaving ceiling height at full behind the beam; that will spread out modal stuff a bit in the front half of the room, and make it so you don't HAVE to use absorbent over your entire ceiling

Hi Steve. Good points. I like the idea of having the choice, i just don’t like muffled rooms, although this is maybe what I will end up with anyway. Here’s V7 ! (there I go again) with the front half of the room having a 6 degres tilt for the ceiling. A little more challenging to build, but I can do it. This is what I am going to do. That being said… Now entering the dreafull brainstorming area… :twisted:

The other option would be to build your inner leaf parallel as you've shown, then frame ANOTHER, inner, sloped hard ceiling to accomplish the stuff in the preceding paragraph; this "false" innermost ceiling could then be vented around the perimeter and filled with insulation, adding more bass trapping WITHOUT taking all the "shimmer" out of the room... Steve

Using the V6 flat ceiling, what about a mix of a standard cloud ceiling and the idea you describe. See bottom view below. I’ve seen something like this in many studio this cloud is slanted, and the center of the cloud is reflective on room side but absorbing on room ceiling side and made from hardwood or slats of wood. The side aera beside the center are absorbing, made just like a regular cloud, with 703 or whatever. That would keep the liveness in the mixing area and at the same time dealing with flutter. That won’t smooth out mode much though.Wadayathink?

Now, how's THAT for raising more questions than I answer??!?

Well... Now we're getting there... :) :D and a couple of :P Thanks alot Steve.

At last my ceiling construction began. I'll post how things are going in a couple of days, now rushing to finnish this out, working alone...Here's some quick pics for yall pics lovers. comments welcome.