ok so i read the rules so im gonna start off fresh..
Im building a small vocal booth in my room..
my goal is to make it soundproof enough so no1 can hear from the outside even if i was yelling, ive read alot recently and most the products i hear about i cant find.. ive already built the main frame heres what ive used..
1/2inch plywood for the floor and roof
1 1/2inch metal studs
1/2inch drywall all around
fire and sound insulation
1inch foam
lots of cocking
the door was cut from the wall framed with the metal studs and put on with a long skinny hinge from home depot
the walls, roof and door were insulated and covered with foam
i cocked every crack before insulation and after the foam, i also used great stuff expanding foam in all cracks and random areas
here is pics of progress
outside
inside before insualtion
inside after insulation foam and cocking
ive recently insualted the roof and used foam to cover like the walls
the floor is still plywood
ive spent about $150 and my budget is around $500
what i was planning on doing next ...
-using strips of foam ontop of exsiting foam as a spacer for air space
-then gluing acoustical cork board all around with a 2inch gap between the cork and the foam
-insualting floor and using mineral wood on top then the cork board
this was my current plan so far but im lost in what direction to go..
would my current plan have any effect?
with what i have as of now what would be the next best step?
and of course any advice is greatly aprreciated..
Some things to look at and think about:
From your description, one of your main concerns is preventing sound from leaving the booth and getting to the outside. This is a sound transmission issue, as opposed to a sound absorption one. Therefore I would begin to understand STC (Sound Transmission Class) ratings of materials and what they mean. Find out how well the materials you have used so far perform in that area. That will help you to understand what more can be done.
Some of the materials you have considered adding (cork, foam, mineral wool) have some absorption characteristics, but little or no effect on sound transmission. As you research, you will find that a material's mass is very important in this area. Cork and foam products obviously have very little mass.
In addition to the STC subject, some other key information to look for regarding your construction is terms like "mass-air-mass" (MAM) and "flanking paths". If you search this forum for these terms, you will find a wealth of information with which to get started. Also search for other examples of booths (there are many), and compare what they have done against your project plan and see what may be different.
My best advice at this point is to understand why those materials may not be suitable before you spend your money or time. Research and planning can save you an awful lot of money and rework. Of course, if you enjoy experimenting with building things in your spare time and don't mind failing a few times, by all means have at it. Many people enjoy this approach. I personally would rather not cut into music-making time by reinventing the wheel.
Understand, I am not being mysterious or witholding the answers. It's just that this type of question and this information has been asked and answered many times on this forum. That's why the search function is provided, so it doesn't have to be repeated. It's just so much more efficient for everybody.
Cool?
The M-A-M concept is going to be critical here, however you may have already built the booth too small to be able to effectively use this technique.
You will need to beef up the outer wall with another layer of drywall, maybe 2 more layers. Use 5/8" drywall, not 1/2" drywall. I would also look into using Green Glue (very expensive) between the layers. This will make a big difference.
Also, using Acoustic caulking rather than "regular" caulking makes a big difference since the acoustic caulking will not harden like regular caulking, and this helps reduce flanking when used correctly (proper gaps between materials, and caulked appropriately).
Next, you will need to beef up the inside of booth as well. The best way would be to use the M-A-M principle, which means that you need to build another frame INSIDE of the first frame. This is going to be difficult as you have sort of painted yourself in a corner, so to speak.
What might be better, is to remove the drywall on the outside of the first frame work, and then leave a gap, and build ANOTHER frame around the outside of the frame you have already built. There should be NO drywall between the frames, only air. (Hence the MAM principle.) Once you have built the second frame, THEN put 2 layers (at least) of drywall on the outside of the booth, and then on the inside of the booth (using Green GLue between the layers). You should also put thick insulation (the pink fluffy kind) between the metal wall studs behind the drywall. Make sure that the outer wall and the inner walls do not touch. You will still get flanking however at the floor and ceiling with this design, but if you do it correctly and use acoustic caulking instead of regular caulking, you might be OK. It might be possible to "float the walls" on neoprene rubber pucks as well to isolate them from the floor.
As far as the ceiling of the booth... plywood is probably not the best choice on its own. I would suggest that you build a frame for the ceiling as well, and then stuff it with insulation, and put a couple of layers of drywall on the inside (once again with Green Glue). You could probably get by with putting a sheet of plywood on the top of the studs between the booth ceiling and the structure's ceiling, but it will be hard to install! The problem here is that your new ceiling CANNOT be attached to both outside walls, that is not good. What you need to do is to make sure that your new ceiling studs ONLY attach to the inside wall (the one that you have already built and need to take the drywall off of). The outside wall (the new one that you still have to build) should probably go all the way from floor to ceiling, whereas the inside walls cannot go all the way to the existing ceiling since there needs to be space to frame in the new booth ceiling. Make sure that the inside walls and ceiling do not touch the existing house if possible.
Your door is not going to be strong enough. You will need a solid wood door at the very minimum, and might need to beef it with more mass even at that. It also needs to be sealed all around with rubber, and even with that, you are going to get some sound leakage.
Next, what are you planning to do about ventilation? That small room will get stuffy very quickly, and become unusable. The singer is going to get cranky and frustrated, and the lack of oxygen will make it worse. There is no window in your design, so there is also the possibility of claustrophobia, which also does not help to bring out the best performance from a vocalist.
So now do you see why we gave you such a hard time before? You jumped into something without understanding what you were up against, and then wanted to know how to fix it! If it were me, I would start all over again! Get some decent plans, read up A LOT!!! I would also go out and buy Rod's book (see the link in the stickys above). This book will teach you a lot about how to build the booth correctly.
What you have designed now will in no way meet your needs as stated. If you can live with that, then you are fine, but if you truly want sound isolation, you are probably going to have to rethink your design, start over, and get some more money.