John Sayers' Recording Studio Design Forum

Greetings everyone,

I have posted here in the past regarding a studio design that never came to fruition for multiple reasons. But now I have a new project that's got the green light so I thought I'd throw it up here for any suggestions, critiques, praises, humiliations, embarrassments, etc. I've learned a ton of info on this site from all you wonderful people and am looking forward to learning even more.

My band and I are converting a detached garage into a studio to be used primarily for rehearsal (loud rock music) but also for recording. We currently rehearse in a small room inside the main house twice a week. The neighbors definitley hear us but we finish by 10:00pm and have not received a complaint in the 10+ months we have been doing it. Nevertheless, we'd like the new studio to be quiet enough to play late into the night (when the creative juices are really flowing). The nearest neighbor's house is approx 40 feet away, however 2 of the garage walls are on the property line with 2 adjacent neighbors.

The garage has concrete brick walls on a concrete slab with 2x10 joists supporting the roof (see 1st pic). There is a plywood garage door with a wooden beam above it, and a window hole that is currently boarded up with plywood. Inside dimensions are 17' x 18' 8" and the height is 8' 2" from floor to ceiling joist. For a mass-air-mass approach, I'm thinking 2 layers of 5/8" drywall on the inside of the garage door (between its 2x3 studs) and between the ceiling joists, along with a plug for the window, should take care of the outer leaf. The inner leaf would be 2x4 framing an inch away from the existing walls, lined with fiberglass insulation, then 2 layers of drywall to close it all up. Since I'm limited on height, I think my only option is RC on the joists to hold the 2 layers of drywall for the ceiling. This should give me a room height of about 8' (depending on how much space the RC takes up).


For the layout of the studio, we want the live room to be large enough for a drum set, bass rig, 2 guitar rigs, keyboard and PA system. I have some ACAD sketches shown below (still learning Sketchup). The first one has a control room with a 1:1.14:1.39 room ratio (one of the most common). This allows for sufficient live room space as well as an ISO booth.

If I rotate the walls 180 degrees (2nd sketch), I can extend the control room to 11', which looks better on Bob Gold's calculator (I think). This also has the main door going directly into the live room, which helps since we'll be moving gear in and out quite a bit for gigs. BUT would this decrease our isolation since the loudest room is now adjacent to the two weakest links (entry and garage door)? Would a double entry door and additional drywall on the garage door solve this?

Going back to the room ratio, I've read that when rooms are this small, maximizing space is more important than adhering to an ideal room ratio. If I angle the walls (3rd sketch) I gain a little more room and eliminate some parallel walls, while only sacrificing a bit of live room space. There's also the inside out wall option, but with the framing only 1" away from the walls, I'm not sure I would gain anything.

So that's a snapshot of where I'm at. Looking to spend $5 to $10k. We'll be doing the construction ourselves and may have some consultants for electrical and/or HVAC if needed. To summarize, here are my first set of many questions: Room ratios or non-parallel walls (or both)? Is having the live room adjacent to the main door and garage door a bad idea? What's the best way to increase isolation on the doors and window? Any other obvious (and not so obvious) layout or construction issues, ideas, recommendations?

Thanks for taking some time to read this. I look forward to your replies.

I like the last one best. Do you have any measurements on the existing isolation? Using a sound level meter and some sine sweeps and drums-bass music to assess it. You might find malling the live room more isolated will put your $ to better use and just treat the CR and booth. Use a pair of heavy doors on the live room entry may get you am decent level of isolation but the ceiling and HVAC penetrations will be as big a concern. You will want plenty of fresh air circulating with a number of people doing high energy music.

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Glenn

Thanks for the quick response Glenn.

I have not taken any sound measurements but plan to do so this week. Are you saying if I beef up the live room isolation then the CR and booth may not need as much isolation? Maybe the inner leaf and framing along the back wall can be replaced by treatment instead?

I was thinking of placing baffle boxes with a couple of turns in between the joists for the HVAC. Double doors for the main entry too, although I'm not the biggest fan of having the main door swing outward. If I turn that last layout 180 degrees, then the entry door goes into the iso booth and could get away with only one door. But then we're loading/unloading gear thru 2 doors, which might not be that big of a deal if the booth/live room door is as wide as possible.

after beefing up the iso and CR you might find just adding slats / absorbers (like inside out walls) may be enough - measure the isolation after beefing up to determine. on the live room with you will have the highest levels, you are effectively creating a large isolation room - spend you money there if that is the biggest issue. then if you have budget - and need the isolation in the other rooms, go ahead and add the additional inner walls before treating.

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Glenn

Got it! That sounds like a great plan. Thank you.

For the live room ceiling, I was throwing around the idea of making a completely decoupled inner leaf by staggering new joists in between the existing joists. The bottom of these new joists would be 0.5" lower than the bottom of the existing joists. This complicates the build but may be worth it if it significantly increases transmission loss. Thoughts? Is that even a realistic option? or should I just stick to RC-2?

inter-leaving the joists if an option and a good one if you can do it.

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Glenn

So I’ve been studying Rod’s book as well as a couple other books on acoustics, and I have an updated plan. I decided to go with the additional joist ceiling between the existing joists. The concrete block walls get pretty warm in the afternoon so I will be needing the full isolation in the CR as well as the live room. I got rid of the iso booth to add a bit more room to the CR and make room for an air conditioning closet. I’m planning on using a window A/C unit located at the existing window space. I need to make a window plug that will accommodate the A/C unit while maintaining my outer leaf. The supply air path will be as follows: A/C closet>duct with In-Line Fan>Silencer Box>Duct>Room. The return air will be: Room>Duct>Silencer>In-Line Fan>A/C closet. Do I have this right?

Since the A/C unit breaks my outer leaf, how do I maintain isolation? Do I build an extra wall around the AC closet (in addition to what's shown)?

How big does the A/C closet need to be? I haven't picked out the A/C unit or fans yet, so maybe I need to do some calculations first?

The rear of the control room is showing stepped walls going around the A/C closet location. I can build some hangers in this area and then a false "rear" wall. Or just make that wall parallel to the CR front wall, which gives me more space for my A/C. I guess I need to figure out how much A/C room I really need first.

Also, should the CR front wall be splayed or extended all the way to the corner with a false wall (both options are shown)?

I really appreciate the help so far. This forum is amazing and I will be making my first donation soon.

A couple of things come to mind with your current design. One is that you do not have a fully decoupled interior framing. The other is that you are using a 24 inch overhead layout,


I , thinking out loud here, would do it differently, to get the decoupling needed and to address the span of the lumber. My sketchup model is representing a 2 X 8 but you could most likely actually go down to a 2 X 6 with a 16 inch layout since we are talking about a span of less than 9 feet that is part of my design.

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Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

Hi Brien. Thanks for your feedback.

Could you please explain why my design is not fully decoupled? I'm just not seeing it. If I have 2x8 joists seated on the internal wall frames, not making any contact with the 2x10 joists of the original ceiling, where is the "couple". I realize that the CR and live room would remain coupled through the inner joists but I'm more concerned with isolation to the outside world.

Your plan splits the room lengthwise, creating two long narrow rooms. This really eats into my usable area, especially since I'm planning on building an A/C closet off the existing window. Things start getting really tight.

I've played around with the layout numerous times and splitting the room that way makes it difficult to have enough room for a full band rehearsal. But if my design is not realistic due to the joist span, then I may need to adjust your design to fit our spacial needs or scrap the inter-leaving joist idea and go with RC-2 to stick with my current design.

OR would going with 16" OC joists allow me to keep the span of my current design?

So many options and so many chances to build it wrong. I'm really glad I'm here.

"If I have 2x8 joists seated on the internal wall frames, not making any contact with the 2x10 joists of the original ceiling, where is the "couple". I realize that the CR and live room would remain coupled through the inner joists but I'm more concerned with isolation to the outside world."

Your idea is decoupled from the existing structure...but the rooms are not decoupled one from the other.

While your want to get no interference from the out side world will work you will have interference from your interior structure since you only have one wall that separates the rooms and this wall is a bridge in your current joist layout.


It is a flanking path.

Break it and get better isolation from one room to the other, you will thank us later.

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Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

"Your plan splits the room lengthwise, creating two long narrow rooms. This really eats into my usable area, especially since I'm planning"


I didn't split anything that didn't increase your areas ability to perform better...what are we talking about here, 1 foot or so?

Your plan had the same effect, with bridging/flanking. Mine removes it.

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Brien Holcombe
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Sound: You can't stop it, you can only try to contain it.

like Brien is pointing out you need to have 2 walls in the middle (angled or not) to create the best isolation there. since your joists run long, you either need to find a way to increase the joist size, or barring a means of spanning it, use isolation clips/brackets and hat channel instead of RC. http://www.kineticsnoise.com/arch/icw/index.aspx consider a small AC closet on the back wall with the necessary baffles to keep it quiet and also duct it into the live room. then build in your bass trapping around it. maximize the volume in the room...

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Glenn