Starting Fresh and Obeying the Laws of Physics

Ok all, I decided to start a fresh thread here. I am attaching my ACAD drawing that I plotted out to a *.jpg, unfortunately it doesn't translate real well but hopefully you all can read it, here is also a ZIP file with a DXF enclosed if you can read that. My problem is that I am trying to span 24 feet for my inner ceiling leaf and of course as we all have experienced, want it all . . right. This is my second studio with the first in a house now sold. I will shoot some photos out on the forum to show you all what I am up to for your most excellent 2 cents. Cheers,

Here is a shot of the building.

And for sh%ts and giggles a shot of my old studio, I sold the house and have all my gear sitting in a pile dying to be released from bondage when I ever get the new one finished.

Greetings Mark I do envy you Americans for having such big garages :) I'm currently building my new studio in a double garage, so you could o a lot worse than read my "Paul's Studio Build diary" here... http://forum.studiotips.com/viewforum.php?f=1 I've hung 6 layers of drywall off 2 x 7 joists on a 15' span @ 15" centres. And the sag of the ceiling is about 2mm ( 1/12" ) I used a demo of a program called Superbeam 4 to calculate the joist size for the span. ( google it, you should find fairly easily. I think it's a UK program, but it doe both imperial and metric. For your application you don't need a floating floor ( unless you haev EXTREMELY HIGH Isolatio needs. I couldn't tell from your drawing whether the floor was to be floating, but just letting you know in advance :) Also you should keep your walls DOUBLE LEAF. IOW, if you existing garage has double leaf walls ( boards on either side of studs ), you should remove the inner original layer first, and build up the outer layer between the studs. you should also put rockwool slabs between the studs of the inner room to dampen void resonances in the void. One of the biggest headaches will be the garage doors. See my Studio Build Diary for more details. adn there' a whole thread at the StudioTips site devoted to them as well. hth :) Paul

Hey Eden - how far into construction are you? Is the existing garage going to be your outer shell? I saw your thread about sound getting into your soffit vents and between your two mass leaves- I had a suggestion to counter that, but it would have meant taking sheathing off the outside wall, and I presumed you already had it up. If you do NOT, my recommendation was to put the heavy mass leaf for the outer wall on the INSIDE of the studs, instead of the outside and under the siding or whatever. If you left the outside sheathing un-sealed (some builders in my area will occasionally just sheath the corners of the house for structural support, but put up foam under the siding) the siding won't act as a sealed mass leaf and you won't get a triple-leaf system. Having the heavy sheathing on the inside of the outer wall will let you vent the roof system normally without worrying about outside air or sound getting in between your mass leaves. I dont know if this does you any good or not. If you haven't started building yet, this may help you out. If not, you've probably got a fix from the other thread anyway.

Got your email, and looked at the drawings. What a refreshing change having the details all there in a manner whee they can be played with. Thanks. Overall the plan looks good. Things that started to some to my mind, nad you may have already addresed them in your mind are power and signal wiring. Being an eletrical engineer, these may be non-issues already to you. I was thinking running all the electrical in the walls and then having troughs in the floor for signal cables. With it being an open space, several circuits of dimmable lighting. The dimmers are either the auto-transformer type or Lutron Grafik-Eye 3000/4000 series in electronic. Any thoughts on variable acoustic panels for the walls? Witht hat space, you could nake the panels large enoough to swing open and create instant goboes/mini-amp traps. Andre

Gee thanks for all the interest . . cool. Paul: I did not have an inner wall so what I have done is to fill the area between the studs with two layers of dywall which is a close to adding drywall to the outside of the building as I can get. My inner leaf will be a separate partition with two or three layers of gypsum, but keep in mind also that I have a very cool viscoelastic polymer that will be sandwiched between the drywall inner leafs. I have looked at you diary and must say good job my man . . good job . . great wealth of information you have shared with this forum. The garage doors will be history come spring as I will be adding additional space for a live area and the doors will go to the dump. As for the sub floor . . hmmm . . I do have an issue here with trains about 500 or so yards away . . also the concrete floor in the garage is somewhat uneven in nature which made me feel that I would need the subfloor . . any additional thoughts on that . . I need more outside to inside isolation than I do the converse as I live in a rural area on about 5 acres where my neighbors really are not bothered by me. I did download the Super span program you suggested, but will need a bit more time to mull over it . . in the meantime I have a structural engineer reviewing my design as well . . so by next week I should have some good suggestions. Dymaxian: The buiding was already built when I bought the property this spring. I have left the outside alone and have filled the area with drywall leaving the inner side empty. My second wall will be a completely new frame with drywall as described above . . . Andre: Most of my lighting will be automated. I am a controls engineer so the lighting and such will be contolled by a Programmable Logic Controller (PLC) with touch screens and distributed I/O across a real time network . . its a real cool way to control power and do cool things with automating doors, camera . . etc . . if anyone would like to know more about that I can help.

Any thoughts on variable acoustic panels for the walls? Witht hat space, you could nake the panels large enoough to swing open and create instant goboes/mini-amp traps.

Being that the studio is an open control room . . your suggestion on the variable acoustic panels for the walls is of great interest . . I have not even considered much of my acoustics (though I need to for sure) as I have been so wrapped up in the sound proofing . . .

edenorchestra wrote:

concrete floor in the garage is somewhat uneven in nature which made me feel that I would need the subfloor . . any additional thoughts on that

I wrote previously about troughs in the floor. This ties in. If you determine that you do not a floating floor, or if to do it with concrete, use self-leveling concrete. A great time to pour the cable troughs right in the floor.

Most of my lighting will be automated. I am a controls engineer so the lighting and such will be contolled by a Programmable Logic Controller (PLC) with touch screens and distributed I/O across a real time network . . its a real cool way to control power and do cool things with automating doors, camera . . etc . . if anyone would like to know more about that I can help.

Sounds good. RFI is the only concern I have, but you are familiar with the stuff. I am not. The use of PLCs sounds interesting.

Being that the studio is an open control room . . your suggestion on the variable acoustic panels for the walls is of great interest . . I have not even considered much of my acoustics (though I need to for sure) as I have been so wrapped up in the sound proofing .

The main factor is what will, change in the walls. Locations of plugs, etc. plus possible recessing of absorbent material etc.

Greetings all . . how's everyone today? Advare:

I wrote previously about troughs in the floor. This ties in. If you determine that you do not a floating floor, or if to do it with concrete, use self-leveling concrete. A great time to pour the cable troughs right in the floor.

My biggest issue is that pouring concrete at this point would be an ungodly pain and would most likely not be an option due to access of the building . . storage of equipment . . and such . . so I must go with the wooden floor to which I have gathered EPDM rubber from my local roofing friend. . . Advare:

Sounds good. RFI is the only concern I have, but you are familiar with the stuff. I am not. The use of PLCs sounds interesting.

No RFI issues with these . . I use them all day long in the most demanding industrial environments . . the communication layer is most quiet as long as you follow the proper wiring topology and specifications I certainly want to entertain quite soon the issue of wiring, and internal sound absobtion but first I woul like to discuss HVAC. I plan to have a centralized system in a mechanical room and am proposing this duct arrangement to be installed in the attic space above the outer ceiling. My question is the compromising of the two ceiling leaves with the supply air. The returns are going to be on pillars (4) running floor to ceiling up the walls . . any thoughts on this?? Regards,

Edenorchestra wrote:

My biggest issue is that pouring concrete at this point would be an ungodly pain and would most likely not be an option due to access of the building . . storage of equipment . . and such . . so I must go with the wooden floor to which I have gathered EPDM rubber from my local roofing friend. . .

Your choice obviously. Leveling the floor with shims will be a time consuming job if you have to do that. As the design considerations progress, Gathering EPDM? Do you know the hardness of it and that it is all from the same type? That still leaves the question of troughs in the floor. Thoughts on that?

I certainly want to entertain quite soon the issue of wiring, and internal sound absorption but first I would like to discuss HVAC. I plan to have a centralized system in a mechanical room and am proposing this duct arrangement to be installed in the attic space above the outer ceiling. My question is the compromising of the two ceiling leaves with the supply air. The returns are going to be on pillars (4) running floor to ceiling up the walls . . any thoughts on this??

Looking over the drawing file (fantastic having that to reference!), the room volume is about 7000 ft^3. Assuming ten air changes per hour and a maximum linear air velocity of 500 ft/min, an effective vent area of 836 "^2 is needed. From what I can tell of your (last) posted drawing, you have 800"^2 of vent opening, but at the main duct only 480"^2 on the main duct. The supply air and return entries are called breakouts in the HVAC industry. Basically the ducts are insulated on the outside with dense material to provide sound isolation. Also the inside is lined with absorbent material. Depending on the needs, vanes are installed in the elbows to maintain laminar flow in the duct, reducing the self noise made by the elbow. Andre

Am I seeing a common supply runner for both rooms, with multiple drops? If so, "do not pass go, do not collect $200..." - for decent iso between rooms, you need separate runs from the air handler to EACH and FROM each room, with longer than normal run length and at least 2 bends per run; Also, don't plan for air outlets that will disrupt the air between you and your speakers, or sit close to your head, etc - injecting cool air in the sound path can cause serious sound anomalies due to changing density of air, actual sound speed, etc - same thing with mounting power amps below speakers in a soffit system; not good... Steve

knightfly wrote:

Am I seeing a common supply runner for both rooms, with multiple drops? If so, "do not pass go, do not collect $200..." - for decent iso between rooms, you need separate runs from the air handler to EACH and FROM each room, with longer than normal run length and at least 2 bends per run;

I think I'm missing something. Is was under the impression that the studio will be one open room.

Also, don't plan for air outlets that will disrupt the air between you and your speakers, or sit close to your head, etc - injecting cool air in the sound path can cause serious sound anomalies due to changing density of air, actual sound speed, etc - same thing with mounting power amps below speakers in a soffit system; not good..

Great points. I had forgotten to think about that at all. If the above (what I wrote) is correct, then the HVAC will have to arranged to address all identifiable control area setups. Forgetfully; Andre

After posting my last post, I had a nagging feeling I had left a key point unclear. Hopefully I am wrong, but just in case I am not, here it is explicitly. Where I wrote about "effective duct area" that meant the resistance to air flow presented by all compnents within the duct system. Where this becomes important, but immediately obvious, is with the duct vents. Because of the effectis of trim reducing gross area, vanes, slats causing turbulence etc in vent covers, the effective vent area is smaller than the physical dimensions of the open area of the vent. The 800 "^2 is close enough. The 480 "^2 in the main duct is not. I hope I got everything this time; Andre

Andre, you're probably right on the single room thing, likely my bad; thought the next step was enclosing the space outside the existing, at which time a CR would be added - that was the scenario I alluded to as far as multiple drops were concerned. If the ducts aren't planned for in advance it could be a real bitch doing separate ones later... Steve

If the ducts aren't planned for in advance it could be a real bitch doing separate ones later..

Total agreement. To plan for for if it might happen will be of minimal, if any cost. Always impressed with your insight; Andre

pheww . . you guys are on top of it . . . Sounds like the whole HVAC needs revamped . . good . . better now than later . . right now the plan is to have an open room . . but then again maybe not . . oh my so confused . . Lets do this . . I have a big open room right now . . if I were to decide to eventually make a separate control room I WOULD be best to make provisions . . I am more than open for a total redesign on the duct work, my guitar player works for a sheet metal fab shop that specializes in insulated ductwork . . but they may have never done a studio, it was their plan that I submitted here . . fresh start? Regards,

edenorchestra wrote:

pheww . . you guys are on top of it . . . Sounds like the whole HVAC needs revamped . . good . . better now than later . .

Hardly a revamp, refining, yes. Like you wrote, better now. Better than turning on the HVAC the first time and having major noise problems. A thing to note (I new I forgot something :) ) the HVAC system, including the ducts should mechanically isolated from the inner room. Not as big a deal as it sounds, suspend the ducts from the outer wall. I am using "wall" in the sense of partition. A ceiling is a wall lyng down. Any thoughts on venting for the bathroom?

right now the plan is to have an open room . . but then again maybe not . . oh my so confused . .

Part of why design is 90%

Lets do this . . I have a big open room right now . . if I were to decide to eventually make a separate control room I WOULD be best to make provisions . . I am more than open for a total redesign on the duct work, my guitar player works for a sheet metal fab shop that specializes in insulated ductwork . . but they may have never done a studio, it was their plan that I submitted here . . fresh start?

From I have seen, there is no need for a fresh start. The start is good. Good studio design is working from concept to completion with attention to many more details than a regular building because the concepts are not relatively widely known in the construction industry, and tolerances are much stricter. Give some thought to what you would like in a control room so that a rough area in the room can be designed for that possibility. A quick note to give confidence in what has been presented so far. the overall duct size to grille is fine. Refinement on the grilles, and that part is done. The main duct needs to increased in size. One major change. I didn't study the return ducts, but the same criteria (500 cfm) applies. Working on the start, have you thought about a noise study around the buiding so we can determine if a floating floor is necesary for isolation from the outside? From what I gather the question is the train tracks. Looking good; Andre

A thing to note (I new I forgot something ) the HVAC system, including the ducts should mechanically isolated from the inner room. Not as big a deal as it sounds, suspend the ducts from the outer wall. I am using "wall" in the sense of partition. A ceiling is a wall lyng down.

I understand this, my plan was to have those ducts above the outer wall in the attic space, still need to understand how they come through the outer through the air space and throuh the inner wall however. The bathroom is partitioned and will have the HVAC equipment in the same room (mechanical/pee room). I will give great consideration to the control area in the next few days.

Working on the start, have you thought about a noise study around the buiding so we can determine if a floating floor is necesary for isolation from the outside? From what I gather the question is the train tracks.

Super good idea, where do I begin, the best thing I have is the el cheapo Radio shack db meter that doesn't go below 50db and god only knows what the curve looks like on the frequency response . . probably a roller coaster . . . your consistent advice is most appreciated . .

I understand this, my plan was to have those ducts above the outer wall in the attic space, still need to understand how they come through the outer through the air space and throuh the inner wall however.

Good on the first point. The second is relatively straightforward, in my mind at least. The attached drawing should help. Nothing is firm in the drawing, it is to give the idea so you can develop the best, including cost, design. A consideration is reduce the number of ducts but increase their size. Check the costs with your friend.

The bathroom is partitioned and will have the HVAC equipment in the same room (mechanical/pee room).

Good to read that. We will have address mechanical isolation for the HVAC equipment. Otherwise it could end turning the entire building into a drum skin for the vibrations. I'll address the noise survey issue when I am more awake. It will require some creative thinking of what is needed, you have and how we achieve it. Sort of like McGyver of Acoustics. Andre

Andre, appreciate the "sleep-posting" syndrome as I'm quite familiar with it - but, where's the outer leaf in your drawing, and how are you decoupling the flanking path (created by a through-duct) between inner and outer leaf? Steve

I haven't forgotten about the noise survey, just haven't figured it out enough yet to post something useful.

knightfly wrote:

Andre, appreciate the "sleep-posting" syndrome as I'm quite familiar with it - but, where's the outer leaf in your drawing, and how are you decoupling the flanking path (created by a through-duct) between inner and outer leaf? Steve

I'm not clear on your questions so forgive the vagueness in the questions. What outer leaf (that isn't there, talk about a confusing sentence) are you referring to? Think of the breakout as being lined duct for outside (in this case to the cavity) ventilation. Flanking path as in something like in the drawing attached? The absorbent material lining the duct. There is no doubt that I have missed something. Unfortunately even with your questions I can't see it. Thanks Steve! As I wrote the above paragraph, I realized something that I DID miss. The duct has to be decoupled from the ceiling to avoid HVAC machine noise being physically transmitted to the ceiling. I will include that revision in the drawing. Andre

I too do not see both leaves in the ceiling. The plan is outer leaf on the chords of the existing trusses with the duct work above that. Then resting on an entirely new wall are joists with the second (inner) leaf. So the duct work is in the largest opening in the truss, that is for the supply Right now I am making a scale model of the building, both to help explain things better and to get my creative juices flowing a bit more . . this will take some time . . but I think it will be worth the effort . . besides that . . its good fun. I bumped the trusses so they're not quite lined up . . Regards,

Nice rendering! I hope this helps. It is based on Edenorchestra's drawing of the proposed HVAC system. This second leaf thing has me confused as much as two of you. Perplexed; Andre [edit] (04-12-07) Read the thread and noticed that my drawing was not attached. Attempted to attach it so that the post makes sense,

I have been giving the noise survey a lot of thought. It is critical because if outside noise is not adequately contained, the weakest point in the sound isolation will make the rest of the work meaningless. If the noise is not a problem then going with a floating floor will be a massive waste of time and money. Paul wrote somewhere recently that the floating floor in his studio is 40% of the construction cost. The noise question, as I understand it, is train tracks about 500' distant. Other sounds, and neighbours are not an issue. Working from what we have spoken about, my first thing was to check that the wall construction is adequate. I modeled a wall with: 1/2" gypsum board, 2 layers 2x4 studs 5" airspace insulation in airspace 2x4 studs 1/2" gypsum board, 2 layers in Insul. The results are shown in the attached JPG. For those reading this who can't see the graphic, the STC is 67 with the TL 30 dB@50 Hz. The wall system will not be a problem with isolating airborne sound from the outside. This confirms our concern being if a floating floor is needed. What we need for the sound survey is at one level fairly simple. 1) microphone with good low frequency response 2) a way of calibrating the microphone 3) electronics to accurately record the microphone output 3) system to analysis the the recording from 3). Where it starts to get difficult is 1) and 3) need low enough noise figures that the self noise does not mask the desired signal. It can be quite expensive to achieve this. That is why the Radio Shack SLM only goes down to 50 dB SPL. Good low frequency response is primarily with omni microphones. Do you have any good omni mics or friends with that you can borrow? Assuming that you do, hook the test mic to your recording system with a calibrated level control, With the test microphone and RS meter side by side outside, record a pink noise source with the RS meter indicating 55 dBC. Note the recording channel settings. Take the test mic to the quietest place you can think of. Put the mic in a heavy walled sound absorbent lined box ( do like that fancy phrase for a road case?) with the just enough open to run the cable. Record again and increase the gain until the level equals what you got from the calibration to the RS meter. This will hopefully give an indication of the self noise level of the mic/electronics. Put that data through software with at least 1/3 octave or preferably FFT analysis capability. Calculate the self noise spectrum. Post/email (hopefully both) the results for review. We will be looking at the overall level and the spectrum to determine the masking. Assuming the above is acceptable, find out when a train is going by and record noting the recording levels sos that we have a calibrated reference to the RS meter. We can then Analise the results. The RS calibration is not great, within 2 dB, but for our work we can take that into account. Another option, and one that would remove any problems with technique band-aid systems would be to rent a suitable meter. Bruel and Kjaer would have setups for that. I do not know the prices of the rental unfortunately. Something like their 2260 Investigator with software.

Thanks Andre . . that's quite a chore . . I will need some time for that. I have to go out of town on business for a few days and then dig out some equipment to run the tests. I will print out your memo which is most helpful. BTW the "rendering" is actually a real model made out of balsa wood that I took a photo of . . everyone that sees it thinks I 3D rendered it on a computer . . cheers . .