Please Help Me Build An Isolation Booth

[Strange]

I am renovating a room in my house right now (Dimensions are 11" 3" X 10' with 8' an ceiling and hardwood floors) and I have decided to make the closet in the room a guitar and vocal booth. Keep in mind I am a carpenter so the labour is not a factor in cost or time. Before I build it, I would like some advice from the forum...

My current design has the booth coming out of a corner of the room like so:
/ \
\_/ The top two slashes (are actually 90*) being the existing walls/corner and the bottom being walls coming from the corners at 90*. The underscore is the door.

It would basically be a 5 sided booth withou any parallel walls. Would this design also help to break up the acoustics of the main room if I were to record a kit in it? Would a simple rectangle or square be better? After the acoustics and soundproofing questions, my main concern is the dimensions. I'd like to keep it as small as possible...

1) Is it possible to make a booth that will be good for both guitar and vocals?

2) What dimensions should I build? I would like it big enough for 1/2 stacks with 100 & 50 W heads, and of course the vocalist.

3) I would like to insulate the walls to limit as much sound outside the closet as possible. I will be staggering the studs but should I use wood or metal studs? Sould I use a layer of 1/2 sheetrock to a layer of 1/2 MDF covered by another layer of 1/2 sheetrock inside and/or outside the closet? Is normal R20 or R15 insulation enough to sound proof? Should the walls be paralell or should angles be incorporated? What would you recomend?

4) Room treatment. Should the entire booth be treated with foam or the "checker" pattern? Ideas for the floor or ceiling? Currently, the floor is hardwood and the ceiling is sheetrock.

5) It would obviously be more convienient to have a power recepticle in the closet. Is there and reason not to put one in there?

6) What kind of door(s) should the closet / booth have? I'd prefer a solid core wood door if I can get away with it.

7) Would I keep the hardwood floor in the booth or treat it as well?

8 ) Is my design for a 5 sided (ie roughly a triangle shape) booth wedged in a corner a sound plan or would a rectangle or square be better?

9) It is possible to build a small window from my control room to the booth. Is this an absolute necessity or can I get away without?


Am I missing anything? Thanks for the time and consideration everyone.

[Strange]

The X at the top left is an old duct incased in plywood and sheetrock that is no longer in use. Entrance to this room is top right.

Dimensions A & B are what I am after. A could very well equal B...

I dunno. My main goal for the booth is solid acoustics utilizing minimal space to be used for drums, etc. Any help would be appreciated. Thanks.

[knightfly]

If you take your last drawing as close to scale, you're showing about a 3' x 3' space; that would be pretty tight/claustrophobic for just a person (think phone booth) -

Isolation of any serious amount takes a mass-air-mass construction, which also eats up space - I've never seen steel studs used in a staggered stud frame - for non loadbearing use, it's not necessary anyway because using 25 gauge studs gives the needed amount of decoupling between inner and outer leaves of wallboard.

Best sizes for booths for minimal coloration due to modes is to use odd #'s of feet, like 3x5x7, 3x7x9, 5x7x9, etc - you can get almost as good with an 8' ceiling using 3x5x8, 5x7x8. What you do NOT want to do is make any two dimensions evenly divisible by each other. All dimensions are to hard surface, NOT including any absorbent materials (yes, absorbend DOES change modal frequencies a small amount but in a small booth it's negligible)

Putting a 45 degree door on a corner booth in that room will probably cause more problems than it fixes; harder to build, plus the door would then be much more likely to return early reflections to the center of the room. This is true whether the rest of the room is a drum booth or a CR. In either case, you may need to put absorbers on the OUTSIDE walls of the booth to control this; another option might be to put diagonal slat absorbers on at least ONE of the booth walls (outside the booth) tuned to a center of around 300 hZ.

Inside the booth; if you leave enough room, another slat absorber can help the inside sound too - tuned to the same general range 300-500 hZ)

Normal mineral wool absorbent should first be placed a couple inches off the ceiling, and more around the booth centered on mouth/mic level to start. IF the booth is still to "live", you can add more. If not, you're done.

That space is going to take some compromise in order NOT to cramp things - you'll probably end up putting thick rockwool across most of your wall/ceiling corners before you're happy, regardless of how big your booth beomes... Steve

[Strange]

If you take your last drawing as close to scale, you're showing about a 3' x 3' space; that would be pretty tight/claustrophobic for just a person (think phone booth) -

Sorry. The diagram was not meant to be to scale...just to illustrate the room's shape and the basic shape of my booth idea.

Isolation of any serious amount takes a mass-air-mass construction, which also eats up space - I've never seen steel studs used in a staggered stud frame - for non loadbearing use, it's not necessary anyway because using 25 gauge studs gives the needed amount of decoupling between inner and outer leaves of wallboard.

Wood it is.

Best sizes for booths for minimal coloration due to modes is to use odd #'s of feet, like 3x5x7, 3x7x9, 5x7x9, etc - you can get almost as good with an 8' ceiling using 3x5x8, 5x7x8. What you do NOT want to do is make any two dimensions evenly divisible by each other. All dimensions are to hard surface, NOT including any absorbent materials (yes, absorbend DOES change modal frequencies a small amount but in a small booth it's negligible)

Putting a 45 degree door on a corner booth in that room will probably cause more problems than it fixes; harder to build, plus the door would then be much more likely to return early reflections to the center of the room. This is true whether the rest of the room is a drum booth or a CR. In either case, you may need to put absorbers on the OUTSIDE walls of the booth to control this; another option might be to put diagonal slat absorbers on at least ONE of the booth walls (outside the booth) tuned to a center of around 300 hZ.

So I assume just building a rectangle shape is my best bet?

Thanks for the info/advice Steve. Much appreciated.

[knightfly]

Rectangles work well IF you stay away from "standard carpenter practice", meaning even multiples of 2 feet. That practice is fine for conserving materials, which is why it's done in the first place - but NOT for acoustics (too many modal reinforcements)

You can also improve on flutter echo a bit by giving the long wall a 1:10 splay, or IOW 6" in a 5 foot wall - If you do that, use the AVERAGE wall-to-wall distance for the dimension between those two walls - IOW, if you want a 5' dimension between two splayed walls, use the midpoint of the splayed wall as your reference and make THAT point 5' from the opposing wall.... Steve

[Strange]

Rectangles work well IF you stay away from "standard carpenter practice", meaning even multiples of 2 feet. That practice is fine for conserving materials, which is why it's done in the first place - but NOT for acoustics (too many modal reinforcements)

Actually, building it 3' X 5' will also leave very little waste.

You can also improve on flutter echo a bit by giving the long wall a 1:10 splay, or IOW 6" in a 5 foot wall - If you do that, use the AVERAGE wall-to-wall distance for the dimension between those two walls - IOW, if you want a 5' dimension between two splayed walls, use the midpoint of the splayed wall as your reference and make THAT point 5' from the opposing wall.... Steve

I'm not completely sure what you are describing here. Do you mean build the closet wall out at an additional 6" to nothing angle?