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2 Car Garage Conversion - 2019 Edition!
Old 10th July 2019
  #1
Gear Nut
 

2 Car Garage Conversion - 2019 Edition!

There is a VERY similiar garage conversion project here:

2 Car Garage conversion to studio.

Looks like the OP does not post on GS anymore. His thread actually came to a final conclusion, so I didn't want to hijack his completed project with mine.

.......

I'll definitely post before and after pictures after a garage clean out.

Primarily, I'm a pianist/keyboardist, composer, arranger, but I also record live instruments, so this is going to be a project studio/Tracking/mixing/rehearsal studio as well. It's a 20' X 20' with a 12' ceiling (highest center point). It's all going to be One general purpose room.

Outside noise level:
1) I'm the last house on a Col-de-sac, so a fair number of cars making u-turns about 20' away from the garage door while blasting loud music
2) Large dogs barking on top of my own little Pomeranian
3) Hovering small airplanes and helicopters ....A high school marching band...
4) Beautiful but extremely loud wild parrots...etc
5) And last but not least constant construction noise from the neighborhood.

Inside noise...I'm not Metal loud, but still too loud. I'm hoping for at least 60 to 65 dB of isolation. That'll definitely take care of the outside noise for the most part.

Overall, soundproofing is my priority. It'd be nice to save some money, but again my goal is to get the job done right. My budget is $25K but I can go up to around $30K if need be.

I'm going with the room within a room approach. I have some general questions:

1) The highest center point of the ceiling is 12' but there are four 10' tall horizontal rafters going from wall to wall. Should I go all the way to the top, or use the rafter for my ceiling height? Personally I would love to take advantage of the full height, but I don't know if that's a good idea from sound-proofing perspective.

2) I'm using the double frame 5/8'' drywall technique with separate top and bottom. Am I suppose to have an airspace between the 2 walls? If yes, how wide the airspace between the 2 walls should be?

3) I probably need to raise the floor. In some threads, sand-filled wooden deck is recommended (over insulation). Is that still the preferred way to go? I'm reading contradicting opinions on this. It's just a concrete slab at the moment.

4) I have a list of mini-split air conditioners that I've gathered from -mainly- older posts. Any newer or better developments in this area? Apparently most companies don't have a show room. A company called Mirage did have an installed mini-split unit (Ventus Inverter 19 - 1 ton). The noise level at low setting is 28dB. That's pretty loud while recording a piano. It's not a deal breaker, but I'd like to hear about your experiences with newer or possibly more popular ones such as SLIM and such.

5) Same for fresh air in take/out take systems. Any recent and better alternatives?


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Old 11th July 2019
  #2
Lives for gear
 

Quote:
Inside noise...I'm not Metal loud, but still too loud. I'm hoping for at least 60 to 65 dB of isolation.
It certainly sounds like you'll need that! But do be warned: you are approaching the limit of what can be achieved on a typical home-studio build... unless you have very deep pockets! Generally, 70 dB isolation is about as good as it can get for your type of build.... and that's talking very big money! Achieving 70 dB isolation is a Very Big Deal. 65 is pretty darn close, in terms of complexity and cost. 60 is fractionally lower, but still lots of money time and effort. Most home studios probably fall into the range 50 - 55 dB isolation, and the owners are very pleased to get that much.

When you consider that a typical house wall only gets around 30 dB (with luck), and that to get 60 dB you need to block one thousand times more sound (yes really! 1,000 times), you get a feeling for why it is hard to do and expenesive. 70 dB implies blocking ten thousand times as much sound as a typical ordinary house wall.

Not trying to scare you or rain on your parade! Just putting some realism into your planning process.

Quote:
Overall, soundproofing is my priority. It'd be nice to save some money, but again my goal is to get the job done right. My budget is $25K but I can go up to around $30K if need be.
You have 400 square feet. 30k means you are planning to spend US$ 75 per square foot. Consider that just laminate flooring alone will cost about US$ 8 to 12 per square foot (installed). The installed cost of the drywall just for your inner-leaf ceiling would be another 7 to 10 per square foot, without even considering the joists, insulation, caulk, nails, etc. That's already one quarter of your budget, and all we have is a ceiling and floor, but no framing, doors, windows, HVAC, electrical, or acoustic treatment. I think your budget is rather on the low side for the level of isolation you are talking about. You could either lower your sights in terms of isolation, or in terms of room size, or both. Or increase your budget!

Quote:
I'm going with the room within a room approach.
Excellent! Because that's the only way you could get good isolation on a tight budget.

Quote:
1) The highest center point of the ceiling is 12' but there are four 10' tall horizontal rafters going from wall to wall. Should I go all the way to the top, or use the rafter for my ceiling height? Personally I would love to take advantage of the full height, but I don't know if that's a good idea from sound-proofing perspective.
The roof you have up there is not going to work as a suitable outer-leaf: too little mass, it' not sealed, and it probably has to be vented in any case. Unfortunately, it looks like you are going to need to do the dreaded "three-leaf" system for your ceiling, which puts limits on how high you can go. Do go as high as you can, yes, and fortunately you do have decent height to start with, so you should be OK. Hint: Use some of the wasted space up there for your HVAC ducting and silencers....

Quote:
2) I'm using the double frame 5/8'' drywall technique with separate top and bottom. Am I suppose to have an airspace between the 2 walls? If yes, how wide the airspace between the 2 walls should be?
Oh yes, most definitely! Your 2-leaf wall is a tuned resonant system. The isolation that you get depends on that tuning to a large extent. The resonant frequency should b no higher than half of the lowest frequency that you need to isolate. In other words, if you need to isolate down to 30 Hz, then you have to tune your resonance to 15 Hz or less. The way you tune it is by adjusting the mass (surface density) of each leaf, and the depth of the cavity between the leaves. Those are the two key factors that control the resonance. So you'll need to choose the correct gap to achieve the frequency you need for the isolation you need. You also have to fill that cavity with suitable insulation, which acts to damp the various resonances going on in there.

Quote:
3) I probably need to raise the floor. In some threads, sand-filled wooden deck is recommended (over insulation). Is that still the preferred way to go? I'm reading contradicting opinions on this. It's just a concrete slab at the moment.
If it's just a concrete slab-on-grade, then you have the perfect floor already! No need to do anything to it. There's nothing better for a studio floor. If you don't like the look of bare concrete, then you could stain it, polish it, lay ceramic tiles on it, or lay thick laminate flooring on it. But don't do anything to raise it, as that would reduce your headroom, ad certainly nothing that has an air space inside it, as that would create a resonant cavity where you do NOT want one. There's nothing wrong with a sand-filled deck... for situations that need it, but you don't. It's not necessary, and would not do anything useful for you.

Quote:
4) I have a list of mini-split air conditioners that I've gathered from -mainly- older posts. Any newer or better developments in this area? Apparently most companies don't have a show room. A company called Mirage did have an installed mini-split unit (Ventus Inverter 19 - 1 ton). The noise level at low setting is 28dB. That's pretty loud while recording a piano. It's not a deal breaker, but I'd like to hear about your experiences with newer or possibly more popular ones such as SLIM and such.
28 dBA is actually pretty quiet. But yes, it still could be too noisy for some scenarios. There is an alternative: use a ducted mini-split instead of a ductless one. The type you normally see on walls is a ductless (or "non-ducted" or "un-ducted"), because it just sucks in air at the top, cools it, the blows it out the bottom front. No ducts. You can also get another type of mini-split, which is designed to be located OUTSIDE your room, and it uses ducts to move the cool air into your room, as well as to suck the warm stale air out of your room. With a ducted system, the actual unit is completely outside your outer-leaf, and you have two ducts as well as silencer boxes that move the air to and from your room. This gives you totally silent operation, if it is designed and implemented properly.

Quote:
5) Same for fresh air in take/out take systems. Any recent and better alternatives?
With a ducted mini-split, you combine the two systems into one! You already have a pair of ducts that are circulating air through the room and the HVAC unit, so all you do is to add a couple of extra ducts to that: one of them dumps a small amount of the warm, stale air overboard to the outside world, and the other brings in the same amount of fresh clean air to replace it. So you have one single system that does both: it supplies fresh air to the room, removes stale air, circulates the rest of the air, and cools it (while also dehumidifying it, of course). It's the smart way to do HVAC for a studio.

- Stuart -
Old 11th July 2019
  #3
Gear Nut
 

Stuart, you've been extremely helpful and I can't thank you enough for your time. I'm gathering more info at the moment, but there are a few things that I can clarify.

1) Yes, I'm aware of the isolation limitations. luckily, I've been this LOUD in my house all these years -including me playing Piano late at night- and that hasn't created a problem for the neighbors. My loud music hardly measures anything by their house, but I've never measured a drum set. I will give it a try when the place is done just to see how loud is too loud. Recording drum set is not part of my workflow so I don't have to worry about it. I'm more concerned with the outside noise leaking into the studio. I'm pretty sure a 50-60 dB isolation will do it for me for the most part.

2) 30K or so is my budget just for soundproofing. I have more funds for treatment. Also, I might get creative and get part of the job done myself with some help.

3) You're definitely right about this roof not being a suitable outer leaf. I gotta wait for the engineer to tell me if the structure can support the triple system.

4) Yes it's a concrete slab-on-grade. Perfect! So glad to hear that I don't have to raise it. I don't like the bare concrete, but laminate flooring sounds good!

5) "With a ducted mini-split, you combine the two systems into one! You already have a pair of ducts that are circulating air through the room and the HVAC unit, so all you do is to add a couple of extra ducts to that: one of them dumps a small amount of the warm, stale air overboard to the outside world, and the other brings in the same amount of fresh clean air to replace it. So you have one single system that does both: it supplies fresh air to the room, removes stale air, circulates the rest of the air, and cools it (while also dehumidifying it, of course). It's the smart way to do HVAC for a studio."

Again thanks for the detailed explanation. I need to show this to the HVAC guy. If for any reason I end up doing the ductless unit, Samsung wind free ductless could be an option. I'm trying to get some info on that as well.
Old 12th July 2019
  #4
Gear Nut
 

I had a rather strange experience with Samsung's authorized dealer today. Samsung's website could NOT be any more ambiguous, so I called the local dealer. The guy didn't want to give me the price for a one ton "Wind free Ductless". He said they combine the labor and unit and that would be my final price after they come for inspection. When I said the receipt should show the amount for the unit and labor, he actually raised his tone a bit! I can understand if they don't want to sell the unit separately unless you buy the installation service from them, but I don't see how Samsung expects people to pay for a product without knowing the price tag! How is this even legal?
Old 12th July 2019
  #5
Lives for gear
 

Quote:
Stuart, you've been extremely helpful and I can't thank you enough for your time


Quote:
1) Yes, I'm aware of the isolation limitations. luckily, I've been this LOUD in my house all these years -including me playing Piano late at night- and that hasn't created a problem for the neighbors. My loud music hardly measures anything by their house, but I've never measured a drum set. I will give it a try when the place is done just to see how loud is too loud. Recording drum set is not part of my workflow so I don't have to worry about it. I'm more concerned with the outside noise leaking into the studio. I'm pretty sure a 50-60 dB isolation will do it for me for the most part.
It would be a good idea to test it out NOW, before you lock in your design. Drums are loud. Very loud. The loudest of all instruments in fact. A drum kit played normally can easily put out 115 dBC, or more. Played hard, it can approach 120 dB: In addition, most of the energy is going out in low frequencies, which are the hardest of all to isolate, and which travel long distances rather well, unlike highs which are attenuated much more over distances, simply by passing through air. If you haven't tried out drums yet, then you are in for a surprise. I'd hazard a guess and say that with your garage as it appears in the pic, a good kit played hard at 3 AM is going to be audible a block away, at least. Your "understanding" neighbors might turn out to not be so understanding after all!

Let's say that you do manage to achieve 50 dB isolation, and that a typical sessions with drums, bass, keyboards, and electric guitars, is hitting 120 dBC inside. That implies 70 dBC outside, a few feet away from the wall. Level does decrease with distance, yes... However, nearby walls, trees, cars, etc. can change that, and "focus" the sound in certain directions. But lets assume that you get 70 dB ten feet from the wall, and that you get the best possible reduction rate: 6dB with each distance doubling. So, 70 dB at ten feet, means 64 dB at 20 feet, 58 dB at 40 feet, 52 dB at 80 feet, 46 dB at 160 feet, and 40 dB at 320 feet. 40 dB is often the legal limit set by noise regulations in many municipalities. You'll meet that at a distance of 320 feet, if you can get a level of 70 dB at ten feet from your wall...

That's probably not what you were hoping for, but that's what the math says...

Same math, but assuming 60 dB isolation, so 60 dB at ten feet from your wall: 60 dB at ten feet means 54 dB at 20 feet, 48 dB at 40 feet, 42 dB at 80 feet, and 36 dB at 160 feet.

So, if you do plan to record drums at some point, you should take this into account! On the other hand, if you are only recording more reasonable level, say around 100 dB, then you should be fine.

Quote:
2) 30K or so is my budget just for soundproofing. I have more funds for treatment. Also, I might get creative and get part of the job done myself with some help.
You can certainly save money by doing most of the work yourself, if you have the skills and the tools. Labor is often around 20% to 40% of building costs, give or take. But if you need to buy or rent tools, the delta might not be as much as you think.

Quote:
3) You're definitely right about this roof not being a suitable outer leaf. I gotta wait for the engineer to tell me if the structure can support the triple system.
Normally when I do that, the "middle leaf" ceiling is supported by the outer leaf, and the inner-leaf ceiling is supported on the inner-leaf walls, as within any other "room in a room" build. So you'd need to find out from your engineer how much extra dead load you can hang from your existing trusses. From what I can see in the photo, there's probably not a lot of extra capacity available! I fear you may have to either beef that up, or run additional joists to carry that load.

Quote:
4) Yes it's a concrete slab-on-grade. Perfect! So glad to hear that I don't have to raise it. I don't like the bare concrete, but laminate flooring sounds good!
That's good news! And just a word to the wise: do not lay your laminate flooring unti the very end! After you have completed building everything else in the room. It's the last thing you should do, for a couple of reasons. One of those is Murphy's law: If you do that early in the build, exactly 7 minutes and 43 seconds after you complete the floor, some clumsy workman will drop a really heavy hammer from the top of the tallest ladder, right in the middle of the floor...

Quote:
I had a rather strange experience with Samsung's authorized dealer today. Samsung's website could NOT be any more ambiguous, so I called the local dealer. The guy didn't want to give me the price for a one ton "Wind free Ductless". He said they combine the labor and unit and that would be my final price after they come for inspection. When I said the receipt should show the amount for the unit and labor, he actually raised his tone a bit! I can understand if they don't want to sell the unit separately unless you buy the installation service from them, but I don't see how Samsung expects people to pay for a product without knowing the price tag! How is this even legal?
Strange! Sounds like that has "scam" written all over it. You might want to let Samsung's head office know about that. Fortunately, Samsung isn't the only manufacturer of good HVAC gear. Mitsubishi is fine too. So is LG. Ditto Carrier, and others. I'm sure Samsung corporate would like to know that you bought form their competitors, specifically because of the way you were treated by their own dealer....

But don't by anything yet! You need to do some math first... you need to figure out things like room-changes-per-hour, air flow rate, air flow velocity, static pressure, sensible heat load, latent heat load, and suchlike, in order to determine what type of unit you need to buy. Getting your static pressure right is rather important: if you buy a unit that can only handle static pressure up to 0.2, and yours is 0.3, then you have a problem! The unit will be overloaded, the fan will be operating far outside of its efficiency range, the motor will be overworked and fail early, and the running costs will be high, while the unit will not actually be able to supply its rated capacity.... Don't guess here! Look at the ASHRAE guidelines on how to calculate all this, to get it right. Warning! Steep learning curve ahead!

- Stuart -
Old 17th July 2019
  #6
Gear Nut
 

Ok, so I still haven't done any critical measurements. I put a pair of JBL loud speakers with a sub in the garage around 8 pm and played some rock music as loud as I could. I checked the levels around the house ...up to the neighbor's doors and walls. Obviously the loudest leak is from the garage door side of the room at the moment. There's no way I could possibly get that loud. I'm convinced a room within a room structure will totally do it for me. Recording drums is not my thing, so I can just forget about that. 55 to 65 db of isolation would be great for my workflow.

Turns out I would need to get some work done on the ceiling before I add any extra load. This house was built in 1960s I think.



"You can also get another type of mini-split, which is designed to be located OUTSIDE your room, and it uses ducts to move the cool air into your room, as well as to suck the warm stale air out of your room. With a ducted system, the actual unit is completely outside your outer-leaf, and you have two ducts as well as silencer boxes that move the air to and from your room. This gives you totally silent operation, if it is designed and implemented properly."

I think I'll be fine with a relatively quiet ductless unit, but this sounds great too. Thanks for bringing it up. I'll definitely discuss this option with my HVOC guy. Would this also require baffle boxes? If yes, then that'll be a total of 4 boxes...2 for the air conditioner and 2 for the HRV.

The floor has a slight slope (possibly for drainage?). Should that be leveled with concrete first, or that's something the flooring guy can figure out?
Old 14th February 2020
  #7
Gear Nut
 

ok, so my project is officially done. We made a lot of adjustments to the original plan. I'm extremely happy with the results. I also wanted to thank this forum for the great deal of assistance that I've received.

This is essentially an ALL IN ONE composing/tracking/rehearsing room. I did not need a dedicated booth at all. The whole thing is a double studded/double 5/8" drywall with added soundboards and in-wall cavity insulation and one layer ceiling. I thought about doing a double layer ceiling, but I wasn't allowed to do so. Turns out I didn't need it at all. As I'm writing this, I hear small airplanes, some construction noise, lawn mower and beautiful sounding birds in the living room. None of this cuts through in the studio. Luckily none of the side streets around me are thru streets, so this whole area is much quieter than most places.

My original measurements at the top of this thread were not accurate. Once I removed everything, the space turned out to be bigger than I thought. After everything, now the internal space is about 19' x 18' with the ceiling peaking at 13' or so. Material cost? I'm guessing between $11k-$12k including the Gree mini-split and Broan Fresh Air system and their installations. Excluding a few little things here and there, I bought most things from 3 stores. (HomeDepot 85% , Lowes 10% and the rest from Ganahl lumber and Amazon pretty much). It took about 6 months to build this space.


All panels are DIY. Even the quilted piano cover is made by a friend.


So here it is:




















Old 14th February 2020
  #8
Gear Nut
 







Old 14th February 2020
  #9
Gear Nut
 
















DIY 4'X8' Skyline Diffuser:























Old 15th February 2020
  #10
Lives for gear
 
Kyle P. Gushue's Avatar
Congrats! Looks like a real comfy place to vibe out and get creative! Best wishes!!!!
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