John Sayers' Recording Studio Design Forum Archive

All,

Location:
I am in Southern PA, USA.

I have read a lot of old posts and spent a lot of time on the
recommended links page. My questions seem pretty specific to my
situation's unavoidable limitations, so I've decided to start a new
thread.

status:
I am working on a plan for a small room for vocal recording. Nothing
built yet.

Goals:
I'm a songwriter/singer working remotely with a mixing
engineer/producer who has a (nice) control room elsewhere on earth.
The space I construct doesn't need to impress customers or the public
and doesn't need a window.

My primary goal is to record vocals which make the life of my mixing
engineer easier---just want to make him as happy as possible. I
believe I understand that in a small room the best I am going to be
able to do deliver a "dead" recording---but that will be better than
what I'm producing now.

The goal is to build a framework I can use to install treatment to
minimize frequency buildup, bad frequencies and other problematic
artifacts. If I'm going to do that, I figure a vocal booth is a
natural approach.

Isolation:
More isolation is obviously good, but my budget and size constraints are
likely to be binding before reaching any serious isolation ambition.

I want to follow the rules, so I'll just say I'm shooting for 50db,
more would obviously be better but I'll live with what I can
realistically manage before my budget includes a cabin in the woods.
I'm not worried about bothering neighbors, but there is a big hvac
thing on the neighboring property which is the bane of my existence
and I'd like to keep it off my records to the best of my ability.

As I stated above, my priority is building a framework I can use for
installing absorption to keep the recordings 'tidy' more than
eliminating every external sound, but the more I can clean up unwanted
noise the better.

Floating:
I will not be floating this vocal booth!

The existing space:
The space is in a basement with a concrete floor. (The floor is far
from level---but I will say something about that in my questions at
the end.)

The ceiling is exposed early 20th century joists on 16'' centers
supporting the subfloor and floor of the first floor of the house.

The cieling limit is only 80'' (~2m). This is obviously not great, but it
is the only ceiling I have.

---existing walls (2 of them)
Not sure how much the walls matter since I am planning to build a box
with four new walls. I want to put the box in a corner, but it
doesn't need to snug to the walls. One of the walls is the foundation
of the building (it is a shared foundation with the neighboring
house. The other is an very old plastered over wall--not really sure
about what is behind that one or its construction.

There is a support beam and a post which account for the other two
constraints of the rectangular location where I want to put the booth.

I could draw a picture, but the punchline is that the total available
open space to build the box is LxWxH = 70''x80''x80'' (1.78m x 2.03m
x 2.03m)

Budget:
I wish I had a number. As far below $1000usd as possible is where I
hope I can land, but the door and all the absorption I'll need to buy
and build makes me nervous.

----

My questions:

0. My existing ceiling is pretty low. Any suggestions about things to
keep in mind when dealing with the ceiling constraints in a situation like
this one?

1. The floor is not level. Do you suggest I use some kind of
self-leveling mix (the stuff you would pour out before putting down
tile) to bring it up to level?

(I've been thinking about just shimming up the baseplates for the walls
and fill the gaps with something later. I'm more concerned about
recording a workable signal that total isolation.)

1a. If I am to level up the floor, should I bother doing the whole
space inside the booth, or just worry about the floor directly below
the baseplates? (I could build some channels and just level the
outline where the baseplates will sit.)

1c. One more question about the concrete floor---should I cover it
with anything? I read a suggestion on the internet somewhere that
stick down tiles of some kind would be the ideal solution---if this is
the case, leveling the whole space under the booth would make sense,
but I'm not sure if there is a suggested treatment for a concrete floor.

2. I'm planning to use a staggered stud wall design (like that shown
in J. Shryrock's thread in the reference area and elsewhere).
Planning on two layers of 5/8th drywall (what you southern hemisphere
types seem to call 'gypsum'). I've thought about using MDF for the
leaves (leafs?) at some point along the way but I haven't seen any
examples of that in my searches through the forums. Is it because the
marginal benefit of MDF over two layers of 5/8 drywall isn't worth the
cost or is otherwise impractical?

2a. Just a side question---I'm sorry I can't seem to find what I
thought I've read somewhere here that the leaves need to "match"...Is
that true? Is there any reason to consider MDF on the outside (or
inside) with drywall in the other place? (I'm sorry if that question
is terribly naive.) I think that the answer is that the leaves should
be the same.

3. I've been somewhat mystified by the best 'shape' of the booth. I
see that John S's vocal booth design has non-parallel walls, and that
makes sense to me, but can (or should) I just copy the angles if the
walls are somewhat different dimensions or should I look to keeping
everything proportional to that design? (Issue here is that the
height will not be the same.)

4. As far as I can tell, the door is the hardest part. Since this
isn't a commercial operation, I was thinking the door could be framed
between the base/topplates for the studs. Is there any issue with
leaving those sections of the baseplates for the studs intact? Just
seems like it would simplify the design quite a bit and I can just
step over the threshold.

Thanks for any comments or suggestions!

Welcome, and other than providing a SketchUp of your space, that is a great and detailed post. Thank you!

there is a big hvac
thing on the neighboring property which is the bane of my existence
and I'd like to keep it off my records to the best of my ability.

Have you measured how loud the unit is? With it on and with it off. Is there any other sounds that are of concern (lawn mowers, rain, people walking around up stairs, etc?)
This is something that will determine your isolation needs.

I will not be floating this vocal booth!

Good. You'd be crazy if you thought it was necessary to do so in your situation.

The ceiling is exposed early 20th century joists on 16'' centers
supporting the subfloor and floor of the first floor of the house.

Cool! This is a great start. The first thing you'll want to do is beef up and seal up the subfloor above. Add a few layers of 5/8" drywall between the joists and backer rod and caulk it. That will provide an outer leaf with lots of mass. Mass is key.

The cieling limit is only 80'' (~2m). This is obviously not great, but it
is the only ceiling I have.

Not great, but that's sadly a common issue people have in basements. And basements are typically the only place people have to build out recording spaces. There's a happy ending to this story. Read below.

I am planning to build a box
with four new walls.

You will need to build more than just 4 new walls. You'll need to build a ceiling as well.

One of the walls is the foundation
of the building (it is a shared foundation with the neighboring
house. The other is an very old plastered over wall--not really sure
about what is behind that one or its construction.

This is one of four corners (I presume) in your basement. Are none of the other three options? Being as far away from neighbours would be ideal.

There is a support beam and a post which account for the other two
constraints of the rectangular location where I want to put the booth.

Again, would one of the other 3 corners be better applicants for the position?

the punchline is that the total available
open space to build the box is LxWxH = 70''x80''x80'' (1.78m x 2.03m
x 2.03m)

Okay, so, you mentioned earlier that your height is 80". That means that the room is 70"x80" square. Two of your dimensions are identical. The third dimension is luckily not within the limit. However, in order to fix the duplicate measurement issue, you'd have to shrink the 80" which would then put you closer to the 70". Then that would be a problem. I REALLY suggest you try and change your dimensions some how. This is a MAJOR problem. You need to stretch that 80" out. You can't change the height. If you stretch out the 70", you'll get closer to 80" which means you'll have an exact cube which is worse than ISIS.

I wish I had a number. As far below $1000usd as possible is where I
hope I can land, but the door and all the absorption I'll need to buy
and build makes me nervous.

If you don't need it to look pretty, this is probably close to a reasonable budget... maybe.

0. My existing ceiling is pretty low. Any suggestions about things to
keep in mind when dealing with the ceiling constraints in a situation like
this one?

Good news. John Sayers invented a building technique often referred to as "inside out". Ultimately, you're going to want a whack load of insulation on your ceiling. This technique saves you ceiling height while providing space above the ceiling to stuff insulation and create enough of a gap to often satisfy a decent resonant frequency of that cavity. Then, you just stuff insulation in your new ceiling joists and you're off to the races.

1. The floor is not level. Do you suggest I use some kind of
self-leveling mix (the stuff you would pour out before putting down
tile) to bring it up to level?

Without seeing pictures, we really don't know how bad your floor is. Ideally, you want it flat purely for comfort. And if it's out to lunch a little bit you can always cut your wall studs a bit longer or shorter to compensate. Then, backer rod and caulk it to death. There are some self levelling products out there that work pretty good and are cheap. Shimming things will just create larger gaps that are harder to fill and will be weak points in your isolation. I wouldn't suggest that.

1c. One more question about the concrete floor---should I cover it
with anything?

That's up to you. It is totally unnecessary. Especially if you're trying to save money. Put your money into a better build. You can add pretty looking things later. A rigid surface coupled to the mass of the earth is the best floor you can have (hence my floating floor comment above).

I'm planning to use a staggered stud wall design

The cost of building a staggered stud wall is only slightly cheaper than a fully decoupled two wall design. Yet, it's performance is no where near as good as a fully decoupled two wall design. So, do a two wall design. If you're building in a corner, you already have two walls and a ceiling of your outer leaf done. You need a wall with a door, and another wall to complete the outer leaf. Then, build a room in it (using the inside out technique of course). This can provide you with VERY good isolation all while not eating up your precious square footage!

I've read somewhere here that the leaves need to "match"...Is
that true?

It is not necessary. But, the thinnest, lightest section of your wall assembly will be the weakest link and that will determine your total transmission loss value. That's why I suggested to beef up the sub floor above. You don't want it ruining awesomely built walls. I threw together an excel file that you can type some values into and see how your design will perform:
http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21373

I've been somewhat mystified by the best 'shape' of the booth. I
see that John S's vocal booth design has non-parallel walls

Typically, it's ideal to have a perfectly rectangular room (acoustically) so that you can use online room mode calculators to help determine how the room will perform and give you a head start in the design stage for treating problematic frequencies/areas of the room. The angled walls are most likely acoustic treatment walls placed in front of the rectangular drywall walls. Google RFZ control room to see what I mean about a room that is square behind all of the acoustic treatment walls.

As far as I can tell, the door is the hardest part.

Hardest, no. A pain in the butt, yes. Potential to ruin your isolation, yes.
Like I said before, mass is key. The only way to get good isolation with a door is to have a REALLY heavy door with great seals. Having a true two leaf decoupled MSM type room means that you need two doors. One on your inner leaf. One on your outer leaf. Like the calculator I provided above, you'll see that having 2 heavy doors with a space (that acts as a spring -- MSM stands for mass spring mass) is how you achieve high levels of isolation. If you only have 1 door, you're relying entirely on the mass law equation and without having insane mass (impossible), you won't achieve the levels of isolation required to keep problematic sounds out. Your best bet is to build your own door. Whether that means buying solid core doors and beefing them up or building doors from scratch.


You never mentioned a few things:
-HVAC. You will need to breath inside your air tight room. With this comes an entire other headache of trying to provide the required insertion loss (basically a term describing HVAC isolation levels) as well as the correct air velocity (so that your vocal mic doesn't pick up a bunch of wind/air register noise). This isn't too hard to design, but is VERY important. You'll need to tap into your existing home system (it should be able to provide enough CFM for a little room like that) or for a price out of your budget, get a mini-split system. Then you'll need to build silencer boxes. Due to the size of your room and the fact that you don't need INSANE isolation, you might be able to get away with only having one large box for supply and one for return. Since you'll only have 1 for supply and 1 for return (ideally you want one per leaf for both supply and return making a total of 4 per room), you'll have to have lots of baffles in the box which means they will be quite long. But, you could mount them vertically on the outsides of your walls.
-Where will the computer/recording gear be situated? How will you hit record and edit on the fly? How will you get things like a screen and mouse into your room without trashing your isolation? Same thoughts go for electrical and low voltage things like your microphone and headphone cabling.

Just a few things to think about. But, to recap, your room dimensions really won't work as they are. Small rooms are hard to deal with in the first place. Throw an exact dimension duplicate into the equation and you've got a recipe for disaster.

Keep us posted!

Greg

Thank you for this reply. A lot to think about.

I don't want to seem like I am fighting your advice---I just want to make sure I am following the logic.

I have a question about the double walls---As I understand it, double wall design are just two "normal" (non-staggered) stud design walls with an appropriate gap.

Would it be problematic to build the walls near the existing walls as a staggered design or would that just make bigger problems?

If I were to build a non-staggered wall for the corner of the booth near the existing walls that would count as a doubled wall.

For the other two sides I would build two walls with non-staggered studs. Would it be worse to build those two "outside" walls with a staggered design anyway?

double wall design are just two "normal" (non-staggered) stud design walls with an appropriate gap.

Correct. Literally a room built in a room.

Would it be problematic to build the walls near the existing walls as a staggered design or would that just make bigger problems?

As I stated before, it is way better to build a true MSM fully decoupled two wall room than to try and do the staggered stud thing. The only real use for a staggered wall in my opinion would be the "party wall" design in townhomes or condos. And yes, it would be problematic because you would have problems even making that design work with your ceiling due to flanking. Until you draw this up in SketchUp Make, you probably aren't able to picture the complications I'm describing. Once you draw it up, you'll see where the problems are and you'll realize that the inside out method in a truly decoupled room is the way to go.

If I were to build a non-staggered wall for the corner of the booth near the existing walls that would count as a doubled wall.

The foundation walls of your home would be your outer leaf. The new wall you frame would be your inner leaf. Does the home construction have a frost wall or is the wall just concrete at the moment? Please post pictures of the space so we can see what is actually going on. And start drawing up the space in SketchUp so we can see dimensions and you can start getting familiar with the software as you'll be drawing up every stud in it!

For the other two sides I would build two walls with non-staggered studs.

Two completely separate walls. Yes. Then you will plop an inside out ceiling on top of your inner leaf walls.

Would it be worse to build those two "outside" walls with a staggered design anyway?

Worse. Yes. Maybe even horrible in my opinion. You'd be throwing away a lot of potential, money, and hard work. You'd be saving next to no space doing so. You'd be flanking at the ceiling and therefore flushing isolation down the toilet. Plus, it would prevent you from using two doors and two doors are essential to good isolation... unless you want the neighbours HVAC unit noise in your vocal recordings still


I look forward to seeing pictures and your SketchUp progress.

SketchUp hints:
- draw the shape of what you're making (ex: a 1.5" x 3.5" rectangle). Triple click it, hit the letter P on your keyboard to select the push/pull tool. Click the inside of the rectangle (which is now dotted looking) pull up or push it down a bit, then type how long you want it (in inches, or put a ' after the number if you want it to be in feet... or you can combine units by actually typing for example 4' 15/16) It will go to that length. Now, triple click it so it all turns blue, right click it and make component. As a component, you can tilt it, move it and copy it. Remember, if you copy it, if you adjust one, they will all adjust since they're linked. If you want to make one separate from the bunch, right click it and "make unique". You can even make groups of them unique. Doing it like this is great for making bulk amounts of lumber. Same goes for everything you make. Drywall, insulation, etc.
- to move things, maybe google "Sketchup inference" You will see how valuable this feature is.
- Each section of your drawing should be assigned to a layer. Go "windows" --> "layers". You can also do a quick google search how to assign components/items to layers. I personally go pretty extreme with layers as it makes drawing new areas easier and it's awesome to see sections later too. I have layers for Foundation, frost wall framing, frost wall insulation, inner leaf framing, inner leaf insulation, inner leaf drywall, doors open, doors closed, silencer outer leaf supply 3/4 view, silencer outer leaf supply 1/4 view, etc, etc. You get the idea.
- Everything is one click, move your mouse, second click in the program.
Hopefully that gets you started without screaming too much.

Greg

Thanks again. I'm on the job. Hectic week so I've been unable to make progress until today.

I wonder if you know of anyone can suggest a posted sketchup files which show the best approach to the doubled wall design. Starting from scratch I'm almost certainly going to be making really stupid mistakes.

I'm going to dig around for a good example here on the forums, but if a human wants to say, "this is a good example of a double wall design done in sketchup" I'll be most appreciative--- if "use the search function" is the answer I'll make do. Seems like I'm likely to find a lot of advice about how not to do it well and I'd like to try to set off with an example of the best prior art.

I have a few questions that seem desperately preliminary:

1. Is it the idea to double the drywall on both of the two walls? (That is, all four leaves?)

2. Should I use masonary anchors for the baseplates of the walls?

thinking about materials, I'm terrified about the cost of insulation. The good stuff is not cheap---any comments about the suitability of the rockwool safe n' sound stuff that can be had at the lowes?

if a human wants to say, "this is a good example of a double wall design done in sketchup" I'll be most appreciative

I PM'd you a sketch up file. Depending on your version of SketchUp compared to mine, you may have to:
- google SketchUp 3D warehouse. Sign in to your account and upload the file I sent you to your 3D warehouse.
- open up your SketchUp Make on your computer and through it, go into your 3D warehouse (window --> 3D warehouse)
- have a blank new session open and click download on the file. It will ask you if you want to import the file into your session. You can either hit yes, or else hit no at which point you can save it on your computer. The new saved version from 3D warehouse will be compatible with your version of SketchUp Make.

1. Is it the idea to double the drywall on both of the two walls? (That is, all four leaves?)

No. If you're in a basement or a commercial building, the shell of the building will be made of something hard such as concrete. That will be your outer leaf. From there, you will frame another wall and on it, you will install the drywall.

Here's a picture showing the foundation, a gap, then the frost wall, then the inner leaf in both normal and inside out configurations. The room at the top of the picture is built inside out. The one at the bottom is built normal.

2. Should I use masonary anchors for the baseplates of the walls?

Follow whatever methods are standard in your region in order to pass inspection. Every wall ever built should be anchored well to the floor. Industrial grade glues are very very strong and when applied correctly will probably rip your wood apart before peeling off of the floor. I have in floor radiant heating in my basement so my only real option is to use glue. Safety should always be your #1 priority in any construction project, so make sure you do it correctly and safely. Building a room in a room often requires engineered ceiling joists. Get in touch with a structural engineer and get his stamp for the product you want to use. If it helps anyone else on the forum sort out what to use, I personally was able to design my inside out ceiling skeleton out of 2 ply 1 1/2"x 7 1/4" LVL stud over a span greater than 19 feet.

I hope that helps you out!