advice on wall construction.

hi, i am located in los angeles, ca. i work on everything from acoustic singer songwriter projects to super heavy metal bands. my wife and i are going to buy a home here in los angeles and i intend to turn a two car garage into a mix room, that i can also do full volume bass, guitar and vocal overdubs with excellent isolation between the iso booth and control room... i would like to have a marshall stack cranked in the iso booth, and barely hear any rumble in the control room with the monitors off. i do need to have a bathroom attached somehow, either added on, or in the space i have shown in the sketchup file. a decent size control room is important to me, as i have a harrison 3232c console, lots of outboard gear, and lots of guitar heads, pedals etc. and i like to have the guitar heads in the control room with me so i can dial them in without leaving the control room. i plan on flush mounting a pair of atc scm25a's until i find a pair of tannoy d215's to be used as mains. air conditioning ducts, placement of vents and type will be figured out after i get the walls figured out. the garage will be located at the back of the lot, with the closest residence about 15 yards from the structure. i would also like to be able to track loud guitars and bass at any hour of the night without reservations of disturbing the neighbors. i am willing to raise the roof of the garage in order to achieve the proper control room ceiling height. the sketchup file is my first attempt at creating a model, and they do not show wall construction, which after reading the tripple leaf vs. double leaf thread, i am even more confused than ever... so, assuming there are no obvious problems with the general studio design..... (the entrance will be in the bottom right corner. forgot to finish that up....) my question is what kind of wall construction should i use and where? budget for studio build including bathroom and pluming is 20k usd max. hopefully i have included all of the info necessary for advice. thanks in advance, beau

Hi Beau, and Welcome! The basic layout of the room itself looks fine to me, but there's a couple of things that caught me eye. 1) I don't think its a good idea to have the bathroom leading directly into the CR, for many reasons, but just starting with "humidity" and "smell" might get you convinced... :shock: 2) Listening position. From your diagram, it looks like your listening position (chair) will be almost exactly half way between the front and rear walls. That's about the worst possible place to put your ears! A theoretically good place to put them is 38% of the way back, but that isn't written in stone: you can vary it a bit, as needed. It's just a starting point. 3) Ratio. You don't show the width or height of the room, so I can't calculate your ratio. If you can post those figures we can see if you have something decent there. 4) Door. You say your entry door will go in the right rear: Do you mean roughly opposite where the bathroom door is now? That would be the best place. 5) You say this is going to be in a 2-car garage: What kind of doors are on there, and where are they in your diagram? (top, bottom, left side, right side). Can you take out the doors and brick up the holes, or does your local code prevent you from doing that? Does code insist that the doors have to be operable, or can you totally disable them and seal them, just leaving the "look" of doors from the street? - Stuart -

thank you for your reply! 1) i will look into making the entrance to the bathroom from the outside of the garage. 2) from the measurements of the length of the room i took, the listening position would be 38% of the control room shell. sitting in the middle of an equalateral triangle. which is actually closer to the console than the actual chair... 3) the width of the control room is 13'5", it must have gotten covered up when i threw in the fancy wood floor ;) 4) the height of the ceiling will be whatever i need it to be.. i dont have the spot yet, but im willing to raise the roof in order to achieve the correct ceiling height.. 5) the doors don't have to be functional. im planning on either a) walling them up from the outside, and coding it as a studio apt. or b) leaving the garage door for looks, and building the shell inside of it after insulating the door and walling it up from the inside. my main focus is which type of walls would work best for this type of situation. i have been reading as much as i can about different types of walls, but im still a bit confused about which kind are best for low end transmition loss... im kind of against concrete walls due to the small space and it would require much more internal trapping and treatment right? thanks beau

1) i will look into making the entrance to the bathroom from the outside of the garage.

Or maybe re-arrange things to give yourself a small sound-lock at the entrance, which leads into all three rooms (bathroom, CR, booth).

2) from the measurements of the length of the room i took, the listening position would be 38% of the control room shell. sitting in the middle of an equalateral triangle. which is actually closer to the console than the actual chair...

Can you post your SKP file, so that I can download it and check that out? I have a feeling... :)

3) the width of the control room is 13'5", it must have gotten covered up when i threw in the fancy wood floor ;)

Great! Now we can figure ratios...

4) the height of the ceiling will be whatever i need it to be.. i dont have the spot yet, but im willing to raise the roof in order to achieve the correct ceiling height..

I tried from 7'9" through to 11'0", and your top 5 are as follows, in order of preference (best to worst): 8' 3" - 1 : 1.62 : 2.29 - (Close to Sepmeyer 1, which is 1 : 1.6 : 2.33) 9' 8" - 1 : 1.38 : 1.95 - (Close to Louden 1, which is 1 : 1.4 : 1.9) 10' 2" - 1 : 1.31 : 1.86 - (Close to Louden 2, which is 1 : 1.3 : 1.9) 8'11" - 1 : 1.50 : 2.12 - (Close to Louden 3, which is 1 : 1.5 : 2.1) 8' 9" - 1 : 1.53 : 2.16 - (Close to Louden 4, which is 1 : 1.5 : 2.2) Any of those will do just fine. I kinda like 8' 3", but all of the above are pretty decent.

5) the doors don't have to be functional. im planning on either a) walling them up from the outside, and coding it as a studio apt. or b) leaving the garage door for looks, and building the shell inside of it after insulating the door and walling it up from the inside.

Cool! You should be able to get good isolation, then!

my main focus is which type of walls would work best for this type of situation.

MSM, undoubtedly! :) Lots of mass and big air gap.

i have been reading as much as i can about different types of walls, but im still a bit confused about which kind are best for low end transmition loss...

The kind that has the lowest MSM resonant frequency! The wall is a tuned system: you have to tune it so that its natural resonance is at a frequency way below the lowest one that you want to isolate. Isolation starts at roughly 1.4 x the resonant frequency, but only gets good at around 2x resonant frequency. So you have to tune your wall l-o-w. You do that with mass and air gap.

im kind of against concrete walls due to the small space

If you have the option, then concrete walls are great! Lots of mass in a small space. The density of concrete is around 2401 kg/m3, which is roughly double that of drywall, so you can get the same amount of mass in half the thickness. That's a good deal! But concrete walls are not cheap or easy...

and it would require much more internal trapping and treatment right?

It is going to require lots of treatment regardless of what material you use to build it. That's the side effect of isolating your room. If you think about it, it makes sense: "isolation" means that you stop sound from getting out, which implies that it stays inside, which implies that the room will not sound good. The actual materials aren't so important here: what matters is getting the correct isolation for your situation, then treating accordingly. - Stuart -

i tried posting the sketchup file, but it is too large for the upload. is there a way to make the file smaller? beau

remove all extra material and components and purge it. best bet - make a copy of the one you have, then purge that one so you can keep the details.

so here is what i am thinking of constructing inside the existing unfinished garage, after insulating the existing garage walls.... the walls between the iso booth and the control room would be 5/8 drywall-green glue-5/8 drywall, frame/loose insulation, 2" air gap, frame/loose insulation, 5/8 drywall, green glue, 5/8 drywall. as for the remaining control room walls, i could probably skip the green glue? or would that be a bad decision? another option would be not to not build a new frame for the control room, and just use the existing garage framing? insulating the existing garage framing, adding mass loaded vinyl, resilient channel and double dry wall? the vinyl might cost a bit more than the additional framing, but i'd be saving about a foot of space in the control room... thoughts? thanks in advance, beau

you could skip the GG on the remaining walls if your goal is really separation between the iso booth and the CR (and the iso booth and the outside). don't skip the other walls though as the garage walls are probably not enough isolation by themselves. remember to beef up the outer walls and existing ceiling space to increase mass all around. consider a damped membrane floor in the isolation booth. you could use GG on the plywood layers there.

so its been a while and finally closed on the house, so ive been able to take some real measurements and i took a video so you could see just how much of a "shack" the construction is... http://www.youtube.com/watch?v=vvsE_ScQ5lM as you can see from the video, the garage has a bit of a lean to it.. so we are going to take off the siding and make all the walls plum again. any recommendations on how to beef up the outside layer? i plan on keeping the look of the original siding as the final outside layer. also, in order to save space on the inside dimensions, i've been looking at using insulation, genie clips/resilient channel, mass loaded vinyl and quietrock 545thx as my inner layer. has anyone had any real world experience with mass loaded vinyl or the quietrock 545? i am aware that it is much more expensive, but in the long run, i think having the extra volume in the control room is going to be worth the cost.. attached is the updated sketchup file with the proposed addition. thanks in advance beau

definitely bring the structure back to stable and strong enough for the added mass and consider 3x 5/8" drywall layers inside the stud flush to the exterior sheathing (or with blueboard if you have nails protruding), then a room within a room using another 2-3 layers of 5/8". on the ceiling - if you can adjust trussing to open the height that would be good then a 3x 5/8" drywall, or enhance the rafters to support the additional mass and then support a ceiling on the inner isolation walls.

thanks glenn! i have a contractor coming out to make sure the existing structure will be able to support all of the soon to be added weight, and if not, we will add extra support where necessary. i am thinking of bulking up the roof with drywall in between existing studs, then genie clips, then quietrock 545... however, its very heavy, and most likely going to be a major pain in the butt to install up there... but... im thinking of keeping the vault in the ceiling, and using hanger traps in the entire vault, then an acoustically transparent fabric as a false ceiling... this way i could use that extra volume up above for the much needed trapping in that small of a room.. also, has anyone had any real world experience with quietrock 545 vs. regular 5/8" drywall? im just trying to look at the difference in cost vs. performance at low frequencies.. and it seems like searching the web is full of arguments for and against both... any ideas? thanks beau

beau wrote:

thanks glenn! i have a contractor coming out to make sure the existing structure will be able to support all of the soon to be added weight, and if not, we will add extra support where necessary. i am thinking of bulking up the roof with drywall in between existing studs, then genie clips, then quietrock 545... however, its very heavy, and most likely going to be a major pain in the butt to install up there... but... im thinking of keeping the vault in the ceiling, and using hanger traps in the entire vault, then an acoustically transparent fabric as a false ceiling... this way i could use that extra volume up above for the much needed trapping in that small of a room.. also, has anyone had any real world experience with quietrock 545 vs. regular 5/8" drywall? im just trying to look at the difference in cost vs. performance at low frequencies.. and it seems like searching the web is full of arguments for and against both... any ideas? thanks beau

A contractor may or may NOT be able to do this...the question is can he/she make a believable argument that might persuade someone who might not be easily persuaded? There is another build going on @ viewtopic.php?f=2&t=16077, you should look in on. I think that removing the siding and "plumbing" up the framing is commendable...but I wonder if you guys understand how labor intensive this is? I also wonder how much out of plumb it is and if maybe you are just worrying over something that will not effect you directly...especially when you consider there are other things to address. Like the sparse connections from one wall to the next, commonly referred to as a "joist"...which you are running in short order of at present. Real world experience with quietrock 545 vs. regular 5/8" drywall is not a question begging for an answer. The REAL question, is can the people that produce quietrock show you some data that reveals what the transmission loss value of this product is since, overall, a simple double framed wall assembly with 2 layers of 5/8 X rated sheetrock achieves what they say, and if you need the transmission loss values and the stc values on that, they can be produced, no arguing no bs. My interpretation of your current structure is that not only can it NOT take the weight of quiet rock, you will not reap any rewards from this product. The inability of the walls to support themselves due to the lack of ceiling joists is the most damning area, but the roof framing it self has yet to be discussed as to how that is actually supported. I see little mass in this existing roof framing, leaks all over the place...you have your work cut out for you. Good luck,

i no doubt have my work cut out for me. i realize that, and it is why i am here making sure i gather as much information as i can BEFORE i start building, modifying, etc. how labor intensive would re-pluming the existing framing be? i am prepared to have the garage rebuilt in order to support the upcoming weight. beau

"how labor intensive would re-pluming the existing framing be? i am prepared to have the garage rebuilt in order to support the upcoming weight." Well, those are two entirely different things (plumbing up the existing structure OR rebuild the entire structure.) and to which you move towards may have more to do with money than can you do it. I would have to node my head at the contractor you are working with and get some input from him/her. If you start getting double talk, then I would look into some other things, like telling us how much money you are willing to throw at this build and what level of isolation you are hoping to achieve..