New Construction in a 2 car garage. Need advice desperately!

And time for an update.... The landlord has still not installed the exterior door so I cannot go and do my db testing yet. Argh! I did go back and measure everything within an inch of it's life and have completed a sketchup of the space. I think it's easier to see my issues now. The main issue I am having is with the exterior door and the hinges on the garage door eating into my space. Again, it's a rental so I cannot remove the hinges or make the door swing outwards instead of in. I did ask and was denied. :( So I am trying to design making the best use of the space I have available. A few addendum's to my previous posts... I will now be using a mini split ductless AC system and not a portable unit in the CR. Should I mount it at the back of the room or the front over the workstation? I need two doors. If you look at the basic design I mocked up ( badly I know...I can barely write my name in the sand with a stick ) you can see the two doors I need. One to enter the space and the other to give me access to storage. I also plan to put my noisy machines ( computer, UPS etc ) outside the space under the storage shelf. At the moment the exterior door swings in and this design is based on that being definite. I did however just talk to the landlord and they are going to see if they can mount that door so that it swings outward which would change my design. I will post an updated version shortly. I really want to maximize the space I have while creating a good sounding room and still have access to the storage I need. I have so many boxes of cables, drives, 6 guitar cases etc that I need to store somewhere. In terms of ventilation, would 2 fans in the ceiling give me what I need? One to push air out and one to pull air in. I really can't seem to figure out the best way to do it. Another question I have is whether to build the 12 degree slant of the ceiling in the construction or to build the ceiling flat and then on the inside do my twelve degree slant? It might be cheaper construction wise to build it flat so they don't have to spend all the time cutting and measuring the 2x4's to get the slant. Any small things like this that can save a few $ would be great but not at the expense of the sound I guess. Moving forward....slowly.

This design seems to make the best use of the space. I also like how the 2 doors create a passage into the CR and I can open them when I'm not working to let air in. I usually don't work at hight levels and when I do it's for about 25 mins at a time. Not even. So I could do my writing with the doors open then close it all up for mixing. I attached the sketchup file if anyone wants to chip in. :D

Call me crazy, but couldn't I do something like this? ( Thanks John!!!) I would leave out the door at the back of the room and possibly move the door on the west wall a little further north so i could still get to my storage.I would aslo leave out the door in the north west corner. I would also make it MAM by leaving out the drywall on the outside of the structure. With this design would I have to calculate room modes and size accordingly? Does this make the best use of the space I have?

It looks reasonable, but seems a bit square-ish. What are the dimensions of the inner-leaf? Also, why do you have doors going into the back of your bass traps??? :shock: That happens at the left front bass trap and close to the middle of the rear bass trap. Bass traps don't need much servicing! Really! :) - Stuart -

Soundman2020 wrote:

It looks reasonable, but seems a bit square-ish. What are the dimensions of the inner-leaf? Also, why do you have doors going into the back of your bass traps??? :shock: That happens at the left front bass trap and close to the middle of the rear bass trap. Bass traps don't need much servicing! Really! :) - Stuart -

Ok here's an updated one. The structure will be MAM so there will be no drywall on the outside of the inner leaf. Dimensions of the inner leaf are 15'4" x 13'4". As far as Squarish goes, would it be better to angle the walls out in the CONSTRUCTION phase or build it like this and then on the inside do my treatments? Attached skp file too.

Ok so in a strange yet not completely terrible turn of events the landlords have decided to remove all the built-ins and give me the entire space to use and finish. I have to try get the design done by Monday next week at the latest so construction can begin. The dimensions are now 19'3" x 17'6" x 8'3" Some immediate questions.... 1. For isolation ( assuming 46 - 50 db ) is it better to use the existing structure and double drywall the inside with Green Glue between sheets or build a stud frame for the inner leaf? 2. Should I still try and slope the ceiling 12 degrees over the listening position or can I use a cloud to take care of that? 3. I have no immediate plans to build a vocal booth. Is that easy enough to do down the line should the need arise? 4. How do I build soffit mounts for the speakers in such a big space and still make the triangle work without me taking up the whole room? Thanks for any help. I desperately need it! WHEW!!

the landlords have decided to remove all the built-ins and give me the entire space to use and finish.

Cool! That's GOOD news!!! :)

1. For isolation ( assuming 46 - 50 db ) is it better to use the existing structure and double drywall the inside with Green Glue between sheets or build a stud frame for the inner leaf?

For max. isolation? Separate stud frame for the inner leaf. ESPECIALLY if you want to isolate drums, bass or other things with major low-frequency energy.

2. Should I still try and slope the ceiling 12 degrees over the listening position or can I use a cloud to take care of that?

What are you trying to achieve? If you are after an RFZ design, then yes, slope the ceiling. If not, then you can skip that. Either way you probably still need a cloud. (A cloud alone will not give you an RFZ, and is there for other purposes.)

3. I have no immediate plans to build a vocal booth. Is that easy enough to do down the line should the need arise?

Yes, if you plan for it now and set aside the space. Otherwise, not so easy.... :)

4. How do I build soffit mounts for the speakers in such a big space and still make the triangle work without me taking up the whole room?

Change the soffit angles! 60 degree intersect is not written in stone: You can vary it up to 90 degrees if you need to. It flattens the sweet spot a little, but widens the sound stage. - Stuart -

Can anyone help me with basic room modes? They start building tomorrow and I can specify the width of the room. I know it won't be exact modaly but if I could build a room that is close to a good ratio i will be better off. I tried using Bob Golds mode calculator but I don't understand how to read the results completely. The room length is 17 feet an the height is 8 feet. I can go anywhere from 16 to 14 feet in width, possibly smaller. Any help is hugely appreciated.

14'11" looks good to me... :)

Thanks Stuart. It's between 15 and 16 feet right now. How do those numbers look?

I looked at all of them between 14 and 16. 14'11 is optimum. Not fantastic, but it beats all the others for modal spread, especially around 73 Hz. But don't get confused here: those dimensions are the measurements for the INSIDE SURFACES of the INNER LEAF, not for the locations of the frames! BIG difference! Two layers of 5/8 with green glue is going to take up a bit more than 1" 1/4, so set all of your frames about 1" 3/8 BEYOND the lines you draw on the floor. That way, once you have the drywall up, the interior surfaces will be right on the lines. same applies in all directions, ceiling too: to end up with an 8" ceiling height, the studs need to be cut 1" 3/8 LONGER than you think, to allow for the extra thickness of the two layers of drywall. Speaking of ceilings.... what dimension of joists are you planning for that? You are going to be spanning 15 feet, with a heavy load of drywall and rockwool, so those are going to be pretty large joists. Did you allow for that in your calculations? Or if you are using a contractor, did he allow for that? This isn't like building a normal house or office: The loads are much higher, and the construction details are far more important. For example, does your contractor know that he MUST lay THREE beads of acoustic caulk on concrete floor, right under each sole plate (bottom plate) BEFORE he bolts it down? One bead goes down the center line, and one on each side of that, closer to the edge. Does he also know that he has to seal everything? Does he know to use backer rod and caulk in between all drywall joints? Does he know that he MUST stagger the joints? Does he know that he must also run a bead of caulk around the edge of each layer of drywall, and that the drywall must not touch the floor, walls or ceiling? Does he know that there absolutely CANNOT be any hard connections between this new frame and the existing structure? Not even a single nail to steady a new wall against the existing ceiling? This is all critical. Etc. There are just so many details that he MUST do right, if you want this to be a success. Just to scare you a bit: If he gets it just slightly wrong, and leaves a tiny, insignificant crack under one wall somewhere, just 1/16" wide and merely a foot and a half long, that crack will transmits as much sound energy as an entire section of wall 8 feet high and 12 feet wide, thus negating the isolation entirely. That's how important precision is. He MUST do it right, or he is wasting your money. I hope you explained all this to him when you hired him? So all you need is one careless workman who didn't bother to seal something correctly, and all you money is wasted: That's why you see people on this forum going to crazy extremes to ensure that their builds are sealed. They seal everything in sight, then seal it again, just in case. Then one more time, for luck. It turns out they aren't so crazy: there is good reason to this madness. Failure to seal wrecks isolation. Failure to get dimensions correct can damage isolation or acoustic response (best case), totally wreck it (average case), or even make things worse than they would have been if nothing at all had been done (worst case). I guess that's just my way of saying: watch your contractor and his builders like a hawk! Inspect everything they do, and make CERTAIN that they do it right. Tell you contractor he doesn't get paid if they don't seal everything correctly, or if anything at all even LOOKS like it might be touching the existing structure, since that IS what you are paying for anyway! If it isn't sealed, it is wasted. If it isn't decoupled, it is wasted. OK, time to stop my ranting and go hit the sack! - Stuart -

If I may confirm all that Stuart has just said by adding .... I had a time delay of 1 to 2 weeks before I could add my 2nd layer of drywall. I had already packed the backer rod and caulking at all corners, ceiling, & floor. I must have gone through a case of caulk. I had check AND check all my work several times ... yet, a couple days before the 2nd layer was to go up, I was crawling around the floor and noticed a DARK spot ?!?!? Sure enough, the caulking had settled a bit, and left a slight gap just below the drywall. It was VERY tough to see ... where I had to grab a small mirror so I could see under the gap. I then went through the entire room checking all seals [re-caulking if in question]. Sometimes HASTE makes WASTE was a positive I came away with.

WOW thanks guys. I was aware of most of that but not all. I will now be meeting the contractor at the site before they start today to make sure they understand what they need to do and if we need to take a day extra or whatever I would rather do that to get it right. One thing though.... There will only be ONE wall framed from scratch here. The wall that runs the length of the room across the garage door. That wall will be framed with 2x4's 16 OC then 2 layers of drywall with Green Glue and the back will be exposed studs with R-13 in between the studs. The rest of the 3 walls will be the existing stud structure of the garage with 2 layers of drywall and Green Glue with R-13 in the cavities. The ceiling will be using 2x8 joists and will be reinforced in the center to take the load of double drywall. This is the plan..... Thoughts?

UPDATE The framing is done. After some fantastic help from Stuart ( Soundman2020 ) I decided to go with resilient channel on the existing garage studs then double 5/8 drywall with Green Glue. Then one new wall of 2x4 16OC with drywall and Green Glue on the inside only. There is a space between the new wall and the garage wall that is large enough for me to use for storage and to keep the computer and gear with fans outside of the CR. The new wall has been correctly framed with acoustic caulk underneath and it does not make contact with anything but the cement slab. Interior dimensions will be 17' x 14'11" x 8'. Electrical is done with a 30amp breaker for AC and lights and a separate 20 amp breaker for the gear. Looks good so far! Getting excited now. Tomorrow is insulation and then they start drywalling. I'll post pics in the A.M.

The framing is done.

Naah, not true! No pics = it didn't happen. :) Seriously, congrats on getting started, and seeing things come together a bit! Sounds good! :) - Stuart -

Pics of the framing. Of course there is always something..... The landlord doesn't like what the contractor did with the electrical. Harumph! So a meeting this morning to discuss before they can do the drywall. Hope it goes well.

Pics! So it DID happen! :) But... what are those horizontal battens across the studs for? :shock: Not meant for mounting the RC on, I hope???? If so, is that method approved by the manufacturer? And even more important: How will your contractor be able to GUARANTEE that not a single drywall screw will ever touch the battens? Remember, that even ONE SINGLE SCREW short-circuiting the RC destroys the isolation of the entire wall. They CANNOT allow the screws to touch the studs or battens, and yet they also MUST achieve the correct depth of penetration of the screws into the RC. How are they going to do that? This is a big question.... 2. What's up with the electrical work? There isn't much visible in the photos, so its hard to see what the complain is, but once again, there is a potential big issue here: Penetrations! You cannot have any! There can be no switches, plugs, cables or light fittings poking THROUGH the drywall: Once again, any hole made by the electrician automatically destroys the isolation you would have achieved otherwise. You should have one singe penetration for the incoming cable, and that should be heavily sealed all around with a putty pack and acoustic caulk, then all of the wiring, switches, plugs and light fittings must be surface mounted on top of the drywall, with nothing going through it (except maybe screws going into RC, but once again there's the issue of how to stop that screw touching the RC...). In other words, you do the drywall FIRST, both layers, backing rod, caulk, tape, mud the hole works, and only THEN can you add the electrical installation, since ti goes on TOP of the drywall, not THROUGH it (except for that one single incoming power feed). Not trying to make you nervous, but these are all major points that don't seem to have been addressed, and MUST be taken care of NOW, before there is any additional advance. - Stuart -

Soundman2020 wrote:

Pics! So it DID happen! :)

Yes it did!! :D

But... what are those horizontal battens across the studs for? :shock: Not meant for mounting the RC on, I hope???? If so, is that method approved by the manufacturer? And even more important: How will your contractor be able to GUARANTEE that not a single drywall screw will ever touch the battens? Remember, that even ONE SINGLE SCREW short-circuiting the RC destroys the isolation of the entire wall. They CANNOT allow the screws to touch the studs or battens, and yet they also MUST achieve the correct depth of penetration of the screws into the RC. How are they going to do that? This is a big question....

OK so I checked with the manufacturer....the RC is mounted on the bottom of the horizontal studs leaving the metal clear of any possible screw contact and able to "bounce" while supporting the drywall. The contractor understands this concept having built quite a few studios before ( this is LA after all ) and I will be there while all this is going on to make sure nothing makes contact.

What's up with the electrical work? There isn't much visible in the photos, so its hard to see what the complain is

The complaint is outside the studio where the contractor ran a short conduit between the main house and the garage. The landlord doesn't like it but to be honest I think there is more going on there as I was originally going to use the landlords electrician to give me the separate breaker for the studio. However I asked repeatedly for his number to discuss it and never heard anything back so moved forward with the landlords approval. We are all meeting at the site tomorrow morning to sort it all out.

but once again, there is a potential big issue here: Penetrations! You cannot have any! There can be no switches, plugs, cables or light fittings poking THROUGH the drywall: Once again, any hole made by the electrician automatically destroys the isolation you would have achieved otherwise. You should have one singe penetration for the incoming cable, and that should be heavily sealed all around with a putty pack and acoustic caulk, then all of the wiring, switches, plugs and light fittings must be surface mounted on top of the drywall, with nothing going through it (except maybe screws going into RC, but once again there's the issue of how to stop that screw touching the RC...).

Ok thanks Stuart. I'll make sure the contractor understands that. So I'll have conduit running around my walls then to the outlets? It will be painted over though so shouldn't be too bad. What about my single main light? Conduit across the ceiling? I'll update again after the meeting tomorrow morning. I hope it doesn't delay us further.

the RC is mounted on the bottom of the horizontal studs leaving the metal clear of any possible screw contact and able to "bounce" while supporting the drywall.

Are you SURE you can mount it that way? Did you clear that with the manufacturer? It doesn't matter what the CONTRACTOR says: it matters what the manufacturer has actually tested in laboratories. If the RC is specifically designed and tested to be used like that, then fine! Go for it! But if this is something the contractor came up with on his own, but has never been tested in a a proper acoustical lab, under controlled conditions and with published results, then you actually have no idea what it might be doing. The contractor may well have used the technique in dozens of studios, but unless there is solid evidence that it works, who knows? Does it change the isolation characteristics of the RC? Does it change the resonant characteristics? Does it change the ability to support weight safely? And most important of all: is it allowed by your local building code? Will it pass inspection? A call to your building inspector will clear up that major point... I guess the basic question here is: If there is no published research on this technique, do you really want to be an acoustic guinea pig? Your call...

So I'll have conduit running around my walls then to the outlets? It will be painted over though so shouldn't be too bad. What about my single main light? Conduit across the ceiling?

It doesn't have to be conduit (although that will work fine) A lot neater approach is to use proper surface-mount ducts. When I do post-production facilities for my customers, I recommend LEGRAND structured cable management / trunking systems. Basically, it is just long strips of plastic "C" sections that you cut to length, attach to the walls / floor / ceiling, put your cables in, then snap on a plastic cover. They make straight runs, curves, corners, switch boxes, plug boxes, distribution panels, etc. : easy and quick to install, neat, easy to add / remove / change wiring, etc. : http://www.legrand.co.za/en/scripts/en/ ... P=440&L=EN http://www.legrand.co.za/en/scripts/en/ ... P=448&L=EN They aren't the only folks who make this stuff, and your electrical contractor can probably recommend alternatives. I only mention Legrand because it is what I'm familiar with, and use often.

I'll update again after the meeting tomorrow morning. I hope it doesn't delay us further.

That's one of the advantages of structured trunking systems: they install real fast! Some of the smaller ducts come with self-adhesive strips all along the back: peel and stick... Done! :) You want fast? They got fast! - Stuart -

Are you SURE you can mount it that way? Did you clear that with the manufacturer? It doesn't matter what the CONTRACTOR says: it matters what the manufacturer has actually tested in laboratories. If the RC is specifically designed and tested to be used like that, then fine! Go for it! But if this is something the contractor came up with on his own, but has never been tested in a a proper acoustical lab, under controlled conditions and with published results, then you actually have no idea what it might be doing. The contractor may well have used the technique in dozens of studios, but unless there is solid evidence that it works, who knows? Does it change the isolation characteristics of the RC? Does it change the resonant characteristics? Does it change the ability to support weight safely? And most important of all: is it allowed by your local building code? Will it pass inspection? A call to your building inspector will clear up that major point...

I checked online again and they say it is no good to mount the RC that way in fact you would get better isolation by attaching the drywall straight to the studs. So another call to the contractor yielded a 7am meeting on site to address that issue. All I can say is....$$$$$$$$$$$$ More pics and updates tomorrow as things progress. Thanks for the Legrand link Stuart....a nice company from home. :D Contractor uses something similar that shouldn't be too expensive either or so he says. I want to have my computer and drives in the storage space on the other side of the new wall I have constructed but I can't figure out a good way to run the cabling through the wall without losing tons of isolation. Does anyone have any suggestions? Is there some kind of sealed pipe/conduit I can buy that allows a small cable run through a wall with some kind of gasket that seals? Any thoughts here would be appreciated. I really want to keep the fans and their noise out of the CR.

... they say it is no good to mount the RC that way ...

That's what I suspected.

So another call to the contractor yielded a 7am meeting on site to address that issue. All I can say is....$$$$$$$$$$$$

Sorry to be costing you money, but it's far better to have us looking over your shoulder like this, and correcting issues as they arise, than for you to waste ALL of your money by only finding out later that something went wrong... That's why it is SO important to post photos as things are happening, to avoid having to backtrack too far. Of course, its even better to take the time to plan carefully and question everything, but in your case you have no more time! So photos an explanations are the way to go. - Stuart -

Sorry to be costing you money, but it's far better to have us looking over your shoulder like this, and correcting issues as they arise, than for you to waste ALL of your money by only finding out later that something went wrong...

Stuart, no need to apologize at all!!! I am externally grateful for having you look over my shoulder. Photo's on their way....

quick question... I have an original limited edition silkscreen of John Lennon from his drawing of himself in a frame with glass. I want to hang it between my monitors. Great inspiration. Is there an acoustic issue with having something like that hanging behind the monitors? I plan to use a room kit (GIK or other) for the acoutical treatment inside the room once I have done my tests.

I am having a devil of a time trying to work out 38% of 17ft!! :oops: Can anyone please tell me what to punch into a calculator to work that stuff out? Thanks!!

Mira Music wrote:

I am having a devil of a time trying to work out 38% of 17ft!! :oops: Can anyone please tell me what to punch into a calculator to work that stuff out? Thanks!!

Convert feet to inches 17*12= total inches 38% would be total inches X .38