Planning a simple practice room build. Help! Did a Sketchup.

[warrenmusic]

Hi, this is my first post, please be gentle!

I have been reading this forum for a little while now, and I have been learning tons. I think I get the idea of why MSM, two-leaf rooms are best for isolation. The air/fiberglass/mineral between the two walls act as the "spring" that absorbs vibration and transforms it to heat before most of it leaks out as sound. Correct?

Anyway, I am in the process of buying my first home; it has a huge backyard that is mostly covered with concrete slabs. Apparently, the previous owner used the backyard as a car shop. My dream is to have a simple practice studio that doesn't disturb the neighbors (especially in the evening)... I would have my 5-piece band practicing in there (we reach 110dB at our loudest, but this is just an educated guess).

I plan to hire a contractor to have this room built (I am not a DIY construction kinda guy, I am super accident-prone, and I own very few tools). Long shot, but perhaps one of you would build it? I am in San Jose, California. If not, the odds are that the contractor I would hire hasn't built this type of room before, so I'd love to have a concept ready for him to execute. My budget is $8K. If I could have it built for less, I might use the rest for acoustic treatment...

Below is the little design in SketchUp.

practice room.skp

The room is about 15' x 22'. This will be built on top of a concrete slab as pictured below.

1) WALLS

-I understand the walls must be airtight, and yet de-coupled. How should I tell my contractor to de-couple the walls?

-Mineral wool or fiberglass? Any pros/cons?

-What material should I have the outside wall made from? I'd like to save as much real estate as possible inside the room, so I'd like to avoid thick things like brick.

-What material should the inside wall be? Drywall? Sheetrock? Is there a difference? What about wood? Costs?

2) FLOOR

-I have a concrete slabs, so I believe I will very little problems with the ground acting as a transducer. Would I need any flooring other than this? Would carpet be good? Do I need to have a "floating" floor if I have concrete? Will this concrete end up coupling the walls together?

3) ROOF/CEILING

-Should it have an angled roof? Does it have anything to do with room acoustics?

-How can the roof be MSM in a cost-effective way? How would I communicate this to a contractor?

4) DOOR/WINDOWS

-How can I have a door/windows without destroying the airtight-ness?

-Does it need to be a double door because of the two leafs?

5) AIR

-I'm assuming I need some sort of ventilation. How can I do this and keep the room isolated, sound-wise? What equipment do I need for five to six people, two with guitar amps? Do I need some sort of air pump?

6) NOISE/PERMIT

-The city says I need to keep it to 50dB, so is this practice room dream even viable?

Any help would be greatly appreciated. And please tell me if I am out of line here...

[Soundman2020]

Hi, this is my first post, please be gentle!

Hi Warren, and welcome!

I have been reading this forum for a little while now, and I have been learning tons. I think I get the idea of why MSM, two-leaf rooms are best for isolation. The air/fiberglass/mineral between the two walls act as the "spring" that absorbs vibration and transforms it to heat before most of it leaks out as sound. Correct?

That's about right, yes.

Anyway, I am in the process of buying my first home; it has a huge backyard that is mostly covered with concrete slabs. Apparently, the previous owner used the backyard as a car shop. My dream is to have a simple practice studio that doesn't disturb the neighbors (especially in the evening)... I would have my 5-piece band practicing in there (we reach 110dB at our loudest, but this is just an educated guess).

Guesses are good, up to a point, and that sounds about right, but real number from a real SPL meter would be better! If it turns out that you guys only ever peak at 90 (unlikely!) then you would be overbuilding and spending more than you need to if you spec it at 110. On the other hand, if you actually peak at 125 (unlikely!) then you'd need a hell of a lot more to get you down to 50. You say "The city says I need to keep it to 50dB,", but how do they specify measuring that? "A" weighting? "C" weighting? (there's a difference at 50 dB, much less at 120 dB). 1 meter from your door? At the boundary line? At the curbside outside your home? At the home of the guy who complained? It depends on the city, You need to make sure you get your numbers accurate. There is a huge difference between saying "50 dB A one meter from the door of the source", and "50 dB C at the curbside".

If not, the odds are that the contractor I would hire hasn't built this type of room before, so I'd love to have a concept ready for him to execute.

Ooops! You will need to "re-educate" him about a lot of stuff if he has never built a studio before! Make it part of the contract that he must buy and read Rod's book seventeen times, from cover to cover, before he even picks up a hammer!!!!

-I understand the walls must be airtight, and yet de-coupled. How should I tell my contractor to de-couple the walls?

Build them totally separate and independent. No mechanical connections AT ALL between them (except for the floor). Ditto for the ceilings. The build er will then look at you as though you just escaped from the looney bin, at which point you show him Rod's book, so he can learn how to do it...

-What material should I have the outside wall made from? I'd like to save as much real estate as possible inside the room, so I'd like to avoid thick things like brick.

If you don't want brick, then you will have to make the wall THICKER (unless you can afford to build of from sheet lead!). The wall has to have mass. Bricks have mass. Anything less massive than bricks means that the wall has to be thicker to get the same level of isolation. Laws of physics.

-What material should the inside wall be? Drywall? Sheetrock? Is there a difference? What about wood? Costs?

Drywall / sheetrock / plaster board / gypsum board. All the same thing, different names. It is good mass, easy to work with, and cheap. Wood is good for trim and some kinds of acoustic treatment.

-I have a concrete slabs, so I believe I will very little problems with the ground acting as a transducer.

It might be a slab, but does it have foundations / footings underneath, that will aloow you to build all this thing on top? Check with your contractor. It might just be a thin chunk of concrete sitting on the ground, which probably will not work for what you want. It's not the end of the world, though: you could still use that as your floor, cut out a chunk of it from around the edge, dig, and pour proper foundations to build your walls on.

Would I need any flooring other than this? ... Do I need to have a "floating" floor if I have concrete?

NO!!!!! Read this. VERY importanta: http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

Would carpet be good?

Probably not a good idea. You want a live floor and an absorbent ceiling. If you don't want a concrete floor, just lay laminate flooring on it.

Will this concrete end up coupling the walls together?

Depends on how you build it! But even so, it probably won't be enough to worry about.

-How can I have a door/windows without destroying the airtight-ness?

Massive doors / windows, excellent quality seals.

-Does it need to be a double door because of the two leafs?

Yes. Unless you wnat to build Rod's special door!

-I'm assuming I need some sort of ventilation. How can I do this and keep the room isolated, sound-wise? What equipment do I need for five to six people, two with guitar amps? Do I need some sort of air pump?

Search this forum for "HVAC". and start reading... You have lots of learning to do!


- Stuart -

[warrenmusic]

Wow, wild that my first and only other post here was 12 years ago about the same exact project. It became a room in my house instead of a detached studio with double walls... hahahaha. Slowly but surely, we'll get there...