Temporary Garage Studio: Let's start with the Floor?

xSpace wrote:

The love is here my friend but you may not know what you are asking.

Why... THANKS. :) I have some questions scattered in here which I put in red. If I can get some answers to these I think I can put together a much more 'real' design in fairly short order. Best, ---JC

xSpace wrote:

I don't recall the dimensions of this room but if I were you I would try to fit a footprint inside of that existing structure that doesn't have any one measurement being equal to or divisible by any other measurement, example gratis: 8 foot by 8 foot OR 16 foot...or 6 feet by 12 feet OR 18 feet, etc.

OK, I can easily do that. The available space is L-front to back: 14' 6" W-side to side: 16' H- 8'3" Q: My initial idea was to make the inner room space 11 x 15' 4" x 7' 6" to conform with one of the 'golden ratios' (1.404) I read about @ StudioTips.com. Does this sound like a good idea? Q: Is it common practice to splay the side walls a bit from square? I have seen this at many 'pro' studios over the years... ie. The corners are slightly off from 90 degrees.

xSpace wrote:

You can do the floor decoupling as Rod suggested if the money and material is available. It isn't a requirement, but you have options if you are so inclined.

Got it. My -main- reason for doing this would be acoustics, not sound isolation. Maybe I have this TOTALLY wrong, but I thought having a plywood floor over 703 would just sound better.

xSpace wrote:

Frame up the walls and install your sheetrock one ONE side of the frame[interior side].

Got it.

xSpace wrote:

But what about the ceiling? If you are going to install a ceiling then you have a different process in front of you. After you frame up the walls, install 1/2 inch OSB sheathing to the interior of this frame. Install your ceiling joists and hang the rock on that. Then install the sheetrock on the wall framing. The OSB will keep the framing erect and keep it[the structure] from falling on your head when it racks from poor construction methods.

LOL. I'll have to consider that. I wish I could pre-determine if it's 'worth' doing the ceiling. The ceiling is currently sheetrock with a couple of inches of R11 pink fibreglass. Q: IOW: How much of the sound transmission is going through the ceiling. If I can predict this I can decide semi-intelligently. Q: The transmission I worry about most to the other rooms in the house are below 200hz. Is the ceiling a prime transmitter of that sound? Q: If I 'do' the ceiling, I take it that I want the new ceiling mechanically DIS-connected from the current ceiling, right? It should be supported and stabilized -entirely- by the new framing, right?

xSpace wrote:

See...no one wants you to get hurt OR anyone some years down the road that might read this thread and think that a temp environment can be built with no effort. Much in the same way that you as a professional musician cannot tell your student how to play at a stellar level without instruction, schooling and repetition. It is easier to build a permanent structure then it is to build a temporary one...and I speak from experience not what I read or some one told me :)

Thank you. You sound like someone who speaks from painful experience and I like that. I wouldn't trust advice from anyone who made things sound easy. But my circumstances are what they are so I'm gonna give it a shot.

suntower wrote:

Q: My initial idea was to make the inner room space 11 x 15' 4" x 7' 6" to conform with one of the 'golden ratios' (1.404) I read about @ StudioTips.com. Does this sound like a good idea?

One of the first compromises is the ceiling encroaching on you. But this is a temp room and you already understand the deficiencies that will result from such a low ceiling. Or at least you should already be aware of how sound will be squashed from this effect. Golden ratios are based on the mathematical equation Pi and have been used with success, or at least no one is really bitchin'. But there are more accurate and tested room ratios that you >could< consider, but is up to you. If you are getting your information from this link: http://forum.studiotips.com/viewtopic.php?p=5570 then this is a great start in reference to your dimensions.

suntower wrote:

Q: Is it common practice to splay the side walls a bit from square? I have seen this at many 'pro' studios over the years... ie. The corners are slightly off from 90 degrees.

Yes it is the effort to remove flutter echo by making a diffuse environment. The accepted standard is 6 degrees off of 90 degrees. You have to look at this when laying it out like it is a square. So we use your 11 feet as a reference. The wall in front of your listening position is 11 feet wide[to the finish interior of the walls, important with all these anal considerations] With that line on the floor you will come back from that line at a right angle, 11 feet. Mark it. On your wall in front of listening position you come in from your existing lines 6 inches per side [EDIT: To be more precise - it takes 1 3/8 inch of rise to achieve a 6 degree angle in twelve inches of run (wall length). The actual measurement you would use, with an 11 foot wall length as a reference, would be 11 X 1-3/8 = 15-1/8 inchs NOT 6 inches :mrgreen: . ] If you mark a line from this smaller mark to the back of room wider mark then you will have the contour that you can install your wall plates at and it will produce a 6 degree angle on either side of the room, added the diffusion, removing the flutter echo.

suntower wrote:

Got it. My -main- reason for doing this would be acoustics, not sound isolation. Maybe I have this TOTALLY wrong, but I thought having a plywood floor over 703 would just sound better.

Well, it would not sound better. It will make sound of some kind but the effort and expense just because it <might> sound better is an incomplete thought. What it can do is add to your isolation and this may be an important issue if this is a requirement.

suntower wrote:

[color=#FF0000]Q: IOW: How much of the sound transmission is going through the ceiling. If I can predict this I can decide semi-intelligently.

Your overhead might rate a 37 STC[as an assembly]. What that means in general is that with the existing walls of your garage rated at an arbitrary 50 STC the ceiling becomes the weak point. But, your ceiling has a better transmission loss then do the exterior walls as they are. Reason being you have, already, mass-air-mass in the ceiling and an air space and the rafters/shingles as the additional mass. With your walls they are coupled and by design may produce anywhere from 30 to 50 points on the STC chart depending on the wall assembly, e.g. brick is better, OSB is good on the exterior, is it 5/8 inch sheetrock on the interior of the room, etc.

suntower wrote:

Q: The transmission I worry about most to the other rooms in the house are below 200hz. Is the ceiling a prime transmitter of that sound?

It can be if it stays like it is. What will happen is the noise will bend through the ceiling sheetrock and get into the air space and travel the path of least resisitance into your residence via the attic.

suntower wrote:

Q: If I 'do' the ceiling, I take it that I want the new ceiling mechanically DIS-connected from the current ceiling, right? It should be supported and stabilized -entirely- by the new framing, right?

Depending on what kind of noise level you are up against you could build your new walls up to the existing ceiling and deal with it. But this is a tricky thing that you are wanting to do. The ceiling could be beefed up from the attic side and this would help your isolation and not be anything that you would have to remove or that would produce ill results in the future, visually speaking. Brien

xSpace wrote:

suntower wrote:

Q: If I 'do' the ceiling, I take it that I want the new ceiling mechanically DIS-connected from the current ceiling, right? It should be supported and stabilized -entirely- by the new framing, right?

Depending on what kind of noise level you are up against you could build your new walls up to the existing ceiling and deal with it. But this is a tricky thing that you are wanting to do. The ceiling could be beefed up from the attic side and this would help your isolation and not be anything that you would have to remove or that would produce ill results in the future, visually speaking. Brien

WOW. Thanks for all the useful info. CEILING: I wonder about the ceiling. The attic is not a particularly friendly place to work in. I certainly -could- add mass to the existing ceiling. What would this entail? a. Attaching a second layer of drywall to the existing ceiling from the garage side? b. Pulling out the insulation, layering panels of drywall between joists (gluing with green glue) then re-insulating? (Assuming that the drywall is strong enough to handle the unsupported 2nd layer... OK maybe this is a stupid idea but I thought I'd throw it out there.) c... Something else? The main thing is to deal with the bass transmission. My <cough> <cough> 'guess' was that the bass was being transmitted through the -walls- more than through the ceiling. But if that's dead wrong than I definitely want to pursue this. But what I want most is the least failure-prone option. IOW: I'd rather do something less effective, if it's significantly less risky, cheaper and faster. FLOOR: Thanks for testing my assumptions. OK, if I stick with a straight concrete floor, I gotta treat it -somehow- right? I'm not trying to beat a dead horse, but since I've never worked in a studio with a concrete floor, I -assumed- that 'wood' would be a <ahem> 'better' surface. I've seen all manner of spec sheets on the STC properties of stone/concrete but never anything about reflections. So... where does one find out the freq response of reflections off of a concrete floor vs. a wood floor. THANKS! THANKS! THANKS! ---JC

Thanks for testing my assumptions. OK, if I stick with a straight concrete floor, I gotta treat it -somehow- right? I'm not trying to beat a dead horse, but since I've never worked in a studio with a concrete floor, I -assumed- that 'wood' would be a <ahem> 'better' surface. I've seen all manner of spec sheets on the STC properties of stone/concrete but never anything about reflections. So... where does one find out the freq response of reflections off of a concrete floor vs. a wood floor.

There is no acoustic sound advantage to wood over concrete on a floor. Andre

Wow. I just read an article on 'surface reflectivity'. I had -no- idea. Fantastic. I think I'll just paint the floor and throw down some rugs.... er.... as everyone tried to tell me. :D In my defense, this is -so- counter-intuitive. I've never worked in a recording space with a concrete floor other than large churches. Actually, the one exception was a large 'garage' but the engineer laid down a basketball court floor to 'warm it up'. Maybe even 'pros' are caught up in this myth. I really had to dig a bit to find articles on this (mainly because the search only worked once I stumbled on the terms 'surface' and 'reflectivity'.) Anyhoo... THANKS! I LOVE saving money and doing less work! ---JC

AVare wrote:

Thanks for testing my assumptions. OK, if I stick with a straight concrete floor, I gotta treat it -somehow- right? I'm not trying to beat a dead horse, but since I've never worked in a studio with a concrete floor, I -assumed- that 'wood' would be a <ahem> 'better' surface. I've seen all manner of spec sheets on the STC properties of stone/concrete but never anything about reflections. So... where does one find out the freq response of reflections off of a concrete floor vs. a wood floor.

There is no acoustic sound advantage to wood over concrete on a floor. Andre

JC, the issue with leaving any existing surface having the drywall attached directly to the existing wood frame is the flanking paths that it can create. Right now without doing anything you believe you are actually double what you want the isolation to the house to be. Mass law would stipulate that a doubling of mass has a value of 6dB in reduction - but that is only for airborn sound wave and does not take into account flanking - the sound physically traaveling through the buildins structure. You could possibly double or even triple the mass - and have NO reduction - if the flanking path is the weakest link as you stand now. No way for me to know this as a fact - only a possibility - due to the fact that i am a little more than 3,000 miles from you. If you don't want to install a room within a room - in it's entirety - then i would strenuously suggest that you consider the use of (at the least) resilient channel (RC-1) for the ceiling and outside walls with a minimum of 2 layers of drywall over this. That - along with your double walls on the interior of the building would go a long way wowards re aching your stated goals. As far as the exterior walls go - I would not bother leaving an air space between the insulation batts in bays - just make sure you do not over pack it - fill with fluffy will be fine. The air space is from face of drywall to face of drywall. Rod

suntower wrote:

In my defense, this is -so- counter-intuitive... ...THANKS! I LOVE saving money and doing less work!

You are welcome. As Phillip Newell wrote in Recording Studio Design, about the only thing that is intuitive in acoustics is that sound reduces in level as the distance from the source increases. It is just one example of why paying for an expert will save you money or it takes a long time to understand all the acoustic factors involved. The 90% in my tag line refers to the time involved for people doing the design themselves. Good luck and keep us informed of your progress! Happy to save your money, Andre

Thanks, If by 'flanking noise' you are including -all- sound transmissable through indirectly through the house I am right there with you. This place is like a science experiment. For example: If I'm in the back bedroom, I can -clearly- hear a conversation in the family room at the other end of the house through the magic of heating ducts. (That's one reason I don't want to add ductwork to the mix.) POSSIBLY DEPRESSING: I did an informal 'ear' test by putting on some easy listening with much bass (Limp Bizkit 'Nookie') setting the speakers to 85db at the mix pos. and then listening in the two connecting rooms. This was horrifying. The Radioshack SPL reads 57 db at 4 ft. from the adjoining wall in either room. The vast majority of the annoyance is from the bass of course (when I pop in a hi-pass filter below 200hz the volume is no longer objectionable to any of the other house members.) But the surprising part? When I reduce the signal to 75db at the mix pos? The level on the other side is reduced to only 51db. IOW: 10 db of reduction at the source gives only 6db of relief to the other occupants. Dunno what that means to my construction other than making me feel less confident that anything can be done with major surgery. QUESTIONS: HOW TO DETERMINE WHERE ARE THE MAIN CULPRITS FOR DUMMIES 1a. Is there any easy way to determine which components are contributing to the bass transmission? For example, is there a way for -me- to get a 1st order approximation of how much the ceiling is a factor vs. the linked walls? Stethoscope? Bread crumbs? 1b. I was hoping to share the one outer-facing wall of the garage as a studio wall. But now you've got me concerned about even -that- if I can't determine how much, and from where, comes the flanking noise 1c. And again, based on the dreaded 'flanking noise', it sounds like I should consider making the ceiling truly independent. The attic space above the garage is a continuous 'tube' that runs the length of the house. My original 'guess' was that the bass wouldn't transmit -up- to the ceiling and then through this space, but now I envision each stud and joist vibrating like 32' organ pipes. 2. I'm willing to throw some money at having a pro come out and give me a quick analysis. A few years ago I asked if there was some 'guild' that I could contact, or if you knew anyone in Seattle that is reliable (and affordable). The few people I've seen who advertise as acousticians charge $$$$$$$$$$$$ and tend to want to do things like college orchestra spaces. Any recommendations? Your Thoughts? THANKS! ---JC

rod gervais wrote:

JC, the issue with leaving any existing surface having the drywall attached directly to the existing wood frame is the flanking paths that it can create. Right now without doing anything you believe you are actually double what you want the isolation to the house to be. Mass law would stipulate that a doubling of mass has a value of 6dB in reduction - but that is only for airborn sound wave and does not take into account flanking - the sound physically traaveling through the buildins structure. You could possibly double or even triple the mass - and have NO reduction - if the flanking path is the weakest link as you stand now. No way for me to know this as a fact - only a possibility - due to the fact that i am a little more than 3,000 miles from you. If you don't want to install a room within a room - in it's entirety - then i would strenuously suggest that you consider the use of (at the least) resilient channel (RC-1) for the ceiling and outside walls with a minimum of 2 layers of drywall over this. That - along with your double walls on the interior of the building would go a long way wowards re aching your stated goals. As far as the exterior walls go - I would not bother leaving an air space between the insulation batts in bays - just make sure you do not over pack it - fill with fluffy will be fine. The air space is from face of drywall to face of drywall. Rod