New Residential Studio Build In California

diaphony · Post by **diaphony** » Tue Dec 13, 2016 11:22 am

Hi there, I started a new build recently incorporating the structure that I had on my property. the building was originally a carport, recreation room for the pool area and a back garage area all under one roof. The roof is continuous with the house with a hallway between the house and the studio area. The studio building is approximately 50' x 17'. Small garages on both ends left me with two rooms about 17' x 17'. I wound up with a 16' x 17' live room (soon to change shape), a 10' x 13' control room, and a 5' x7' vocal / guitar amp room. I made use of what I had. I also will have a small entry area to where one can open all doors to all rooms (the live room will have two doors). The entry are has its own antechamber area with doors to be installed. The overall height is close to 9', with the live room having a vaulted ceiling up to almost 11'. I will post a diagram later this week (Sorry about the lack of metric usage). I know the control room is a bit small but when I bought the house a few years back, this are seemed to be calling to be made into a studio. I was also able (not done yet) to make a double walled construction on all side walls. I live in a area with large lots (for a populated California city) and needed to drop a few dB's. I have done a few tests with this already and am having outcomes better than I though. I have used rock wool in all studio walls. Two layers of 5/8" sheetrock with a layer of GG between (did a lot of research on GG and viscoelastic compounds - fascinating, but for another post). I did want to do a DIY compound but I am getting older and don't want to mess with it time wise. The ceiling will be an issue, more on that later. Mitsubishi ductless AC to be installed in the two large rooms. I have a fairly large attic area for a lot of blown in insulation. All light to be LED's. All wiring fed of a 100 amp stand alone sub box with metal conduit. Some lighting circuits are regular romex, all 12/2 with ground.The live room will be started when I am done with the other rooms. I Will post more later on. Time to finish some electrical.

Vocal1.jpg

Vocal2.jpg

Studio1.jpg

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Studio3.jpg

Soundman2020 · Post by **Soundman2020** » Tue Dec 13, 2016 1:28 pm

Hi there "diaphony".

I didn't notice any questions in your post, so there's nothing to answer, but I did want to mention that I noticed quite a few things that just don't jibe. For example:

I have done a few tests with this already and am having outcomes better than I though. I have used rock wool in all studio walls. Two layers of 5/8" sheetrock with a layer of GG between

So it seems you are aiming for fairly high isolation, but then your photos show that you have chopped huge holes in your drywall, and poked electrical boxes through them! That makes no sense at all, to be blunt and honest. Why go to all the trouble of building a high-mass wall, on separate studs, and all the expense of putting Green Glue in between the layers of mass, and then blow all that away by making huge gaping holes in it?

I was also able (not done yet) to make a double walled construction on all side walls.

I don't understand what you are saying there. You say that you were able to do a "double wall", but then you say that you did not do that yet, yet your photos appear to show exactly that! And why did you say that you only did double wall construction "on the side walls"? Why did you not do it in the other walls as well? double-wall construction only works when it is done on the entire room: all walls, and the ceiling. If it is done on only one or two walls, then it will not work. The entire inner-leaf room must be fully decoupled from the outer-leaf room, and that is impossible unless all of the walls are done the same way. It is a physical impossibility to have a fully-decoupled 2-leaf MSM room-in-a-room system if only one or two walls are decoupled.

I will post a diagram later this week

That would be very helpful, yes, because I'm not understanding the layout and wall construction details very well from the photos and the explanation.

Mitsubishi ductless AC to be installed in the two large rooms.

That takes care of your heating and air conditioning, but you didn't mention your plan for ventilation, and there's no evidence of any ventilation in any of your photos, so I very curious about how you accomplished that. Where are you hiding the ventilation system?

I wound up with a 16' x 17' live room (soon to change shape),

Why? If the room is already complete, then why would you want to change the shape? And how would you accomplish that without creating a three-leaf system at some point? The room is also rather small, and changing the shape implies making it even smaller: that's probably not a good idea.

50' x 17'. Small garages on both ends left me with two rooms about 17' x 17'. I wound up with a 16' x 17' live room (soon to change shape), a 10' x 13' control room, and a 5' x7' ...

Unless you tell us about the final finished height in each of those rooms, it is not possible to draw any conclusions or make any predictions about the acoustics, or what treatment you might need. You did mention an "overall" height of 9', but didn't say which room that was for. You also mentioned that the LR will have "a vaulted ceiling up to almost 11'", but you didn't mention how low that goes at the edges. Also, vaulted ceilings are notoriously difficult to isolate: What is your plan for that? will you be building it "inside-out" or conventionally? If conventionally, what shape will the inner-leaf trusses take?

A 10'x13' control room is very small: the recommended minimum size is 220 square feet: yours is only about half of that. It is possible to do a control room with a smaller footprint, yes: I have designed several that are smaller than optimum. But the smaller the room is, the more treatment it needs, and the harder it is to tune. Treatment takes up space in a room, making it even smaller. Are you aware that this is not going to provide good acoustics? The room is just too small for that. Are you aware that you will not be able to use diffusion in that room? It is way too small for numeric-based diffusers. What is the basic design concept for the room? Are you planning to make it LEDE, NER, CID, RFZ, MR, etc.?

I also will have a small entry area to where one can open all doors to all rooms

That is wasted space. Not necessary at all, and the space you lost there could have been put to much better use in the control room. When designing an entire studio inside a very small footprint, the first priority should be to maximize the space in each room, not to include "nice to have but unnecessary" entrance lobbies.

The entry are has its own antechamber area with doors to be installed.

That sounds like even more wasted space...

I also noticed that all of your framing is not decoupled at all, and also does not appear to be anchored to the slab. Why is that? I would imagine that CA building code definitely requires anchoring all sole plates to the slab! Did your framing inspector pass that, like it is? Or has your inspection not yet been done?

There's just a lot of things in there that don't seem to make sense. I hope I'm wrong about them, and I have just missed something in there, but I have a bad feeling....

- Stuart -

diaphony · Post by **diaphony** » Tue Dec 13, 2016 6:52 pm

Hi Stuart.

Thanks for the reply. You have an extensive background and I appreciate that you would make yourself available to reply. I tried to minimize errors using what I have learned from reading, etc. I will try to reply in order and help make better descriptions. I clearly made less than adequate explanations to begin with.

Please look at the drawing. I will explain a bit. The house I bought lacks outside storage area for me. To solve a few issues, I pored a continuous slab (purple marks) next to the unlabled room, the live room, unlabled entry area, vocal and shop area. This area was under a very large roof covered walkway (The entire roof covers both garage and house being continuous). I then built the 3 storage areas and the studio entry area on top of the slab making an entire double wall to the west. The purple marking to the west of the vocal room and the north part of the live room is a heavily insulated second wall (matching insulation with all the walls denoted by purple - Rock Wool) with a 6 inch air gap away from the original wall. The unlabled room most north, a second wall was also place there. I will eventually insulate the most north wall of the unlabled " shop" area. The southern walls (labeled shop are) are insulated (Rock Wool)/ The eastern wall is not yet a double wall. The whole side in a concrete driveway quite isolated from the neighbors with a tremendous amount of vegetation. The east side is the loudest at this time (Sheetrock up but not mudded or taped or 2nd 5/8 interior sheetrock in yet. On this side (east) I can also use more than two layers on 5/8 sheet rock and GG. I also have the option of building an entire 2nd wall several inches from the current exterior. That side of the building has a 3 foot eve and I could easily build a second exterior wall if needed. The exterior of the entire building is (probably old growth, sad) 1 1/4" Redwood siding (Mid century modern house built in 1957) internally sealed with OS 175 caulking prior to insulation. Crawl space above is another issue. I think the only thing reasonable is to bury it with blown in insulation when the last wiring and AC is completed.

1) Holes in the sheetrock: All wiring was done in clad except for a few lighting circuits that are LED only. The holes you see are fully sealed boxes (expanding foam insulation) and buried in rockwool. The axxess panel opening will be moved shortly to the entry area. It is just open at this time for no good reason. I tried to be very careful around any holes and cracks, sealing everything I could find. It was quite a project in itself to seal everything.

2) Decoupling: It wasn't my goal to do that. Many walls were there to begin with and I would be unable remove entire walls and erect new ones. I will be here for about 5 more years. I wanted to build something somewhat useful, learn a few things, built a stand alone studio at my new house. My goal was to make use of what I have in the best manner available withing a set of reasons (compromises) I could only minimize things, not fix everything anew.

3) Ventilation: The only thing I can think of is to use a/c flex tubing (8" diam?) and some sort of fan system that can exchange air. The good thing is, this will be a limited use studio for me and friends. The time will be limited. A busy day would be for 2 to 3 hours with the same amount of people. I am not sure how large a problem that will be. I could always add a ventilation system. There is enough room for one in the attic. I am planning doing more about this as I get closer to installing the AC/Heater unit.

4) Acoustics: I know its a small room. It will have short comings. Hopefully, they wont be intolerable. Hence my research on resonators.I could have offset the room and not had a vocal area, a little larger. I can still do that, I have no problem incorporating that area, the vocal and entry. The control room is sized upon a ration though. The live room, haven't got there yet although the vaults are spaced by 2 x 8's and I can insulated and cover with material. They drop to 7'10" on the sides.

5) Framing: I used 1/8" solid rubber underlayment between the bottom plates, top plates, where ever a new stud stud or plate touched concrete or an existing wall. Blue screws (concrete anchors) were used. (small and not photographed well).

With the control room, I was planning on testing (I have some room simulation software and then seeing what issues arrise. I will post the results after the sheetrock is finished. Let me know if you have further thoughts. Thanks you for your previous post again. I would rather fix a wall issue now than later if it will make a good difference.

Jonathan
California

StudioPlan1.jpg

Soundman2020 · Post by **Soundman2020** » Mon Jan 16, 2017 5:10 pm

quite isolated from the neighbors with a tremendous amount of vegetation.

Vegetation is actually not very good at isolating sound. Studies show that typically you get around 8 dB of reduction, which might reach as high as 15 dB for a very dense, very thick, and very tall vegetation barrier, carefully built in layers. You'd probably get around 5 dB for typical garden shrubs and small trees.

That side of the building has a 3 foot eve and I could easily build a second exterior wall if needed.

... which would create a three-leaf system that could potentially REDUCE isolation for low frequencies. Are you aware of the so-called "three-leaf problem"? Walls that have three leaves in them will always provide LESS isolation, especially for low frequencies, than an equivalent two-leaf wall, all other factors being equal.

I think the only thing reasonable is to bury it with blown in insulation

Insulation by itself does not stop sound. It's pretty lousy at isolation. On the other hand, when correctly used as the damping element in a fully-decoupled 2-MSM wall, it greatly increases the total isolation. But on it's own, it doesn't do much. Think of it this way: A sponge is really good at mopping up water that spilled some place you didn't want it. But if you take that same sponge and hold it over the end of the tap, then turn the tap on full, the sponge does a really lousy job of stopping the water from getting through. That's what happens with sound going through porous insulation. Insulation is great at "mopping up" sound that spilled someplace, but really lousy at preventing sound from getting through.

Blown-in insulation can potentially create flanking paths, and conversely the process can leave empty voids. Neither is any good for isolation.

The holes you see are fully sealed boxes (expanding foam insulation)

Expanding foam is acoustically useless. It has very low mass, so therefore it is not use at all for stopping sound, and it is also closed-cell at the microscopic level, meaning that it is also terrible at absorbing sound. What you did there is no use.

I tried to be very careful around any holes and cracks, sealing everything I could find. It was quite a project in itself to seal everything.

Sealing is definitely good, but only when it is combined with mass. The ONLY thing that stops sound, is mass. Solid, hard, heavy barriers is what stops sound. Sealing is very necessary to maintain that, but only if the mass is continuous around the entire room. If there are places in the wall where the surface density (mass) suddenly gets lower, such as for example the place where a very thin-walled electrical box pokes through a massive hole, then that is a major weak-point. Since the surface density (mass) is so much lower at that point, in fact the rest of the wall does not matter at all.

If you have a wall where the surface density is (for example) 25 kg/m2 across the entire surface, except for an area where it drops to only 3 kg/m2, then as far as sound is concerned, the entire wall looks like 3 kg/m3. Even if that area is very well sealed, absolutely air tight, it makes no difference. The key to isolation is mass, and since that area has no mass, it also has no isolation. If one part of a wall has no isolation, then basically the entire wall has no isolation.

2) Decoupling: It wasn't my goal to do that.

Then you wasted a lot of money on all that mass! Sorry to be so blunt, but that's the harsh reality. If you do not decouple the two sides of a wall (meaning that they are fully coupled), then adding mass to your walls is subject to an equation of physics know as "mass law". It goes like this:

TL = 14.5 log (Ms * 0.205) + 23 dB

Where:
Ms = Surface density in kg/m2

Basically, what that means that every time you double the entire mass of the complete wall, you get a measly increase of about 4 or 5 dB in isolation.

On the other hand, with a fully-decoupled wall, you get an increase of about 18 dB each time you double the mass.

Many walls were there to begin with and I would be unable remove entire walls and erect new ones

That would not have been necessary. All that you needed to do was to decouple the mass on the second leaf.

My goal was to make use of what I have in the best manner available

Unfortunately, you didn't accomplish that. What you did is not the best manner available. You used a manner based on mass law, when you could have used a manner based on resonance. You would have gotten an increase in isolation that is at least one order of magnitude greater, for less money.

3) Ventilation: The only thing I can think of is to use a/c flex tubing (8" diam?) and some sort of fan system that can exchange air.

The good thing is, this will be a limited use studio for me and friends. The time will be limited. A busy day would be for 2 to 3 hours with the same amount of people. I am not sure how large a problem that will be.

The average person breathes in about 12,000 liters (400 cubic feet) of air per day. Roughly 20% of that is oxygen, and about a quarter of that is used up and converted to carbon dioxide, which is then exhaled. That's for a person at rest. A person doing light to medium exercise, such as a musician jamming away happily, will use up all the available oxygen from one cubic meter of air (35 ft3), in about fifteen minutes. So, three people will use up all of the oxygen in one cubic meter, in about 5 minutes. You'd need to have a volume of about 36 cubic meters in order to provide enough oxygen for those three people for three hours, but the volume of your control room is only 25 m3. Let's say my calculations are off by a factor of 50%: You'd still need 18 cubic meters (630 cubic feet) of air in the room, to provide enough oxygen to keep the musicians alive.

But that's only half of the problem: The "burned up" oxygen is turned into CO2, and thus the level of CO2 in the room will increase with each breath exhaled. Before the room runs out of oxygen, the CO2 level will reach lethal levels. The air you breath in contains about 0.04% CO2. The air you breath out contains about 5% CO2. Each exhaled breath contains about 25ml of CO2. So four breaths is 100 ml, and 40 breaths is one liter. A hundred liters of CO2 is enough to raise the concentration of CO2 in a cubic meter of air, to levels that will cause you to pass out. So 4,000 breaths will do that. Typical breathing rate for people doing light to moderate exercise is around 30 per minute, so in about two hours you'd produce enough CO2 to do that. Three people will do that three times faster, so in about 40 minutes there will be enough CO2 in one cubic meter to send all three of you unconscious. In three hours, that's 5 cubic meters of deadly air inside your room. As near as I can tell, your control room is about 25 cubic meters, so one fifth of the air in that room would be deadly. But long before it knocks you out and kills you, it produces drowsiness, headaches, loss of concentration, dizziness, and nausea, among other unpleasant things that are not very useful for musicians trying to keep a beat and stay in tune! At only 1/10th the toxic level, you are already getting those effects...

So within about an hour or so, the three of you will already be enjoying the wonderful health effects of reduced oxygen and increase CO2 levels in your room.

So yeah, I'd say that ventilation is something you might want to consider for your studio!

4) Acoustics: I know its a small room. It will have short comings. Hopefully, they wont be intolerable.

Did you take a look at ITU BS.1116-2, or EBU Tech.3276? Those are the specs you should be aiming to reach, as much as possible.

The control room is sized upon a ration though.

Which one? There are several good ones. Assuming the numbers in your post are correct (13' x 10' x 9') the ratio is 1 : 1.11 : 1.44, which fails one of the BBC critical tests for control rooms, and is outside the Bolt area.

I used 1/8" solid rubber underlayment between the bottom plates, top plates, where ever a new stud stud or plate touched concrete or an existing wall.

Did you do the math for that? What durometer is the rubber? What Shore scale? How much deflection are you getting for the load? What resonant frequency does that produce?

Blue screws (concrete anchors) were used.

In other words, you short-circuited any decoupling effect that might have been there, by creating very solid mechanical flanking paths directly through, from framing to concrete, totally bypassing the rubber...

I was planning on testing (I have some room simulation software

Room simulation software is not a bad thing, but room simulations are only as good as the boundary conditions that you set in the software, and even then the predicted results very often do not match the actual measured results. In order to run a simulation correctly, you need to know the acoustic properties of all of the surfaces fairly accurately,but from what you say it seems like you don't yet have a treatment plan, so I'm wondering how you came up with the properties for the walls when you did your simulation. What coefficient of absorption did you use for each surface in the simulation, and how many sabins did you assume for each surface?

Rather than use simulation software, I'd suggest that you download REW and use that. REW is proper acoustic analysis software, that will measure the actual room response and display that in many different ways that are very useful for making decisions about how to treat the room.

Thanks you for your previous post again. I would rather fix a wall issue now than later if it will make a good difference.

I'm attaching an image that shows the basic concept of how your walls should be done, in order to achieve high levels of isolation.

MSM-two-leaf-WallChunk-conventional-.png

That's the way to fully decouple two-leaf walls. Not shown on there is that the inner-leaf ceiling does not touch the outer-leaf at all. It rests only on the inner-leaf walls.

For slightly lesser (but still good) isolation, it is possible to decouple the inner-leaf on single-framed walls, by using either resilient channel ("RC") or by using RSIC clips and hat channel.

- Stuart -

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