John Sayers' Recording Studio Design Forum Archive

Hello, all.

Just found the board and I've been having a gret deal of fun reading through many of the posts. I've even gotten some great resources while trying to get as much info before posting my question. Excellent resources!

I install Crestron controlled Home Theaters for a living, and I am installing a new project studio into an apartment I just moved into for video and music editing. With some amazing luck, I found a landlord who didn't mind me making physical alterations to the apartment, so out with the ugly wood paneling, and in with new sheet rock, 5.1 surround & Ethernet wiring, and pre-wire for my future plasma in the living room!

I am building the studio right next to the living room in 5.1 surround as well, raised floor, and with lines running into the patch from the living room for XLS and TRS inputs. Since I'm demo-ing the walls down to timber to prepare for sheet rock and insulation, I'm just making the design layout now for the control room. Hence my first question:

My control room faces forward at a neighbor's interior wall. With the plaster just removed from the walls, I am looking at the back-side of their wall. My speakers with be on along that wall, left, right and center. I am down to timbers and I need to use an insulation to make sure they can't hear anything, otherwise my late-night sessions will be painfully quiet.

The other issue is, since I don't own the apartment, I want my materials to be cheap or free. AND FIRE RATED; since I just watched my neighbor's house go up in flames, I'm being very code conscious in this old Brooklyn/Williamsburg house.

PICTURES: 1st; wall of the neighbor facing west, 2nd; looking at studio before ripping down plaster, facing North.

Any recomendations would be great! I found the SAE construction guides WAY helpfull too!

Thanks!
=flynn

Flynn, how's it going? There are certainly more experienced and more qualified experts than myself moderating and browsing this forum but one thing I noticed from your post is your desire to use some sort of insulation in a wall to help keep it quiet for your neighbors. Insulation won't do much in terms of reducing noise levels. What you need is to add mass to the wall to help with noise levels. Insulation would help with absorbing sound but not blocking it's transmission. If I misunderstood your post, please forgive me. Also, finding any building materials for free is extremely difficult, especially for the amount you can potentially need for studio constuction, depending on your needs/goals. Hope this helps a little. You'll find amazing advice and resources throughout this forum.

Chris

I think your going to have to build a second wall with an air gap to help block sound transmission to your neighbors
first make sure the inside of that wall is air tight with good cualking
and then insulate it, then build your second wall with an air gap and more insulation and caulking
lots of time and money unless you like working with headphones.
hope this helps

flynn wrote:I want my materials to be cheap or free. AND FIRE RATED; since I just watched my neighbor's house go up in flames, I'm being very code conscious in this old Brooklyn/Williamsburg house.

I'm glad to see a fellow "code conscious" person here. I get ribbed a bit here for being "the worry wart" about code compliance (and I'm by no means a code expert).

That being said . . . The photos are proof that you've already begun construction by way of demolishing the existing party wall. I'm pretty certain that's illegal -- you've destroyed most of the fire protection between you and your neighbor! Now, I realize you have to break a few eggs if you're going to make an omelette . . . But starting construction without a building permit is illegal, and I can't imagine you could get a permit without having detailed plans to present to your municipality for approval.

I would be more sympathetic if you just poked a large enough hole to inspect the anatomy of your existing construction. That's something that could be easily patched. It's not "the point of no return," where you are now.

I'm fairly certain that you've put a lot of people at risk so far -- you, your neighbors, and your landlord, whose hazard insurance may refuse to provide coverage if something really bad happens and it can be proven that you were doing construction without a permit.

I realize "there's no turning back now," so your best bet is probably to get things "safe" as quickly as possible. That means not showing these photographs when you get your permit.

In fact, now that I think about it, I believe it is your landlord who will need to secure the permit, because he (or she) is the homeowner!

And the municipality may have restrictions on a "homeowner" construction permit, in that either the homeowner must do the work himself, or a licensed contractor must do the work. (You mentioned that you install home theaters for a living -- are you a "licensed contractor"?)

If (gasp!) you weren't planning to get a permit, realize that most municipalities can levy substantial fines if they find out, even after construction is complete . . . And they can still require the entire job to be destroyed so that they can inspect each stage of construction to ensure code compliance.

I realize I'm putting you on the spot here, and I'm drawing attention to things for which you didn't seek advice or comment . . . But I feel a moral obligation to warn you and others -- especially in multi-family construction cases -- that there are huge risks to demolishing now and planning later.

OK... Lecture's over (for now). Now let's move on to some of your questions.

. . . I need to use an insulation to make sure they can't hear anything . . .

YAAAAAAAAAAAAAAAAAAAAAAA!!!

Ordinarily I'd say . . .

HA HA HA HA HA HA HA HA HA HA HA!!!

. . . but given your "I've already started it and put many people at risk" situation (oh-oh, lecture creeping in again!), it's too frustrating to be funny.

There is no such thing as "insulation to make sure they can't hear anything."

The best insulation, I think (others may disagree), given your situation, is Thermafiber Sound Atteuation Fire Blankets (SAFB) - Nominal Density (2.5 pcf) or Roxul Acoustical Fire Batt (AFB) - ≥2" (2.5 pcf). The "two and a half pounds per cubic foot" weight of this stuff makes it ideal for applications such as this, and it will also satisfy your firephobic tendencies. However, it isn't cheap or free. Prepare to spend some cash on this.

I'm guessing that neither you nor your landlord will tolerate much of a square footage loss to build a true "room within a room," so you'll probably have to resort to hanging multiple layers of gypsum wallboard (a.k.a. "sheet rock") on resilient channel (i.e., "RC").

Yikes -- you also have to figure out a way to "beef up" the neighbor's wall (your "outer leaf"). With that plaster-and-lath situation you've got going I don't know how to advise you there. Maybe slapping on a couple of layers of plaster will help.

Do you have neighbors below you as well?

Finally, have you read and followed all of the guidelines in the "Before You Post" announcement? Including everything in the Reference Area? I'm thinking you have a long way to go to learn about what soundproofing is and what it isn't -- and given your "no turning back now" situation, you need to read and learn all you can fast.

That's all the time I have this morning. Good luck.

--Keith

Thanks all,

No, I am not licenced contractor. I usually work with a GC, an electrician and an acoustician professionally, but for the work I'm doing, I wanted to do it myself to learn. The landlord has been flexible enough to let me do that. He is a certified electrican, so I would have expected him to tell me about the permits. Of course, I don't do acoustic engineering professionally, but I have been a sound engineer for over 15 years. This is my first swipe at doing the construction part. Yes, while not a newbie, I'm getting alot out of this board. Thanks to all.

With that said, and my demo already done, I've got some work to do quickly.

I like the thermafibre idea, I'd need 64 sq. ft. and a local seller has it for $32 for 80 sq ft. Well within my "cheap" definition.

I had planned on making that a double wall, and lifting the floor. I don't have neighbors below yet, but that could change. I know that I can't stop ALL transmission of sound with the budget constraints I'm working with, that would require much more than I have at my disposal (Sharward ). I just to make sure that I don't get complaints a'plenty.

I looked at the SAE site for construction, and I think that sealing the wall would work well, and adding the therma fibre and second wall would at least keep the neighbors from thinking they just got a new stereo in their wall, while satisying my fire phobia. They give a great overview of the build here: http://www.saecollege.de/reference_mate ... stics3.htm.

Thanks! Keep the suggestions coming! (I'll talk to the Landlord about the permit...)

I can't tell you guys how much I love this forum! (well, sure I can ) I've been finding so much usefull info that my head is spinning! I've been wanting to know about so many things that you have listed all through this great board. Can't get enough!

Ok, blathering aside. I did some more research and bought some materials, and I'm ready to go do some more shopping to get this done, but wanted to post my latest plan for this wall. I feel given my budget, I'll probably only spend a total of $100 when all's said and bought. Only paid $30 for 85 sq. ft of the Roxul! (Thanks Sharward!)

As you can see in the picture I've included, I'm adding 2" Roxul Mineral Wool to the back side of my wall against the neighbors side in-between the studs, which are 2 2x4s lined up on edge together. Nothing I can do about them since they are load bearing.

Please note the air gap, I want to make sure I'm doing that correctly.

Then I'm using the Acoustical caulk (yellow) to glue the plywood (tan) to the tibers. Then, I'll be adding two more layers of gypsum over the plywood building up the mass of the wall.

The floor is lifted according to one version on the SAE website on construction (I stole the image. Heeeeheeeee).

Opinions? I feel that this should be adequate sound insulating for the environment given that I'll be doing mostly mixing and not much recording besides vocals, keys or guitars. I'll have more insulation left over, so I can double up in a few places.

(and I checked with local ordinance, for the minimal changes I am doing, NY state does not require a permit to replace the interior skin of a wall, i.e. removing plaster and adding sheetrock. )

flynn wrote:I'm adding 2" Roxul Mineral Wool to the back side of my wall against the neighbors side in-between the studs, which are 2 2x4s lined up on edge together. Nothing I can do about them since they are load bearing.

Please note the air gap, I want to make sure I'm doing that correctly.

I think you're mistaken -- the insulation you are using counts as "air" in the "mass-air-mass" equation. (If you can blow air through it, it's considered "air.") You're using "the good stuff' (insulation-wise) but not enough of it. You want to fill the cavity so that there's "light compression" of your gypsum wall boards. If not, they may vibrate (resonance). The point of the insulation is to dampen your walls (i.e., keep them from ringing). Think of a bell that you are placing your hand on to silence.

In addition, if you don't fill your walls with the stuff, it won't offer the fire protection that the stuff is famous for.

Then I'm using the Acoustical caulk (yellow) to glue the plywood (tan) to the tibers.

Acoustical caulk is not glue. You need to use screws as well.

There's a lot of debate here regarding whether or not it is best to use actual glue though. One school of thought is that you're allowing multiple layers of material to act as one, thereby reducing its resonant frequency (a good thing). However, there may be some benefit to allowing them to flex independently. I'm afraid I don't have time to search and point you to the specific threads that discuss this. Search for "glue" and "resonance" by author "knightfly" and you're likely to find them though.

Then, I'll be adding two more layers of gypsum over the plywood building up the mass of the wall.

You realize that plywood is inferior to drywall in terms of its density (and, thus, soundproofing), right? And it's much more expensive than drywall too. I'm not clear on why you're not just using multiple layers of drywall -- you'll get better performance for less money.

In my case I will be using at least one layer of OSB in addition to multpile layers of gypsum wallboard -- but that's so I can freedom of hanging anything anywhere, and I'm also building load bearing walls and that will (I think) help make the walls more rigid and less likely to sway. I don't think you have to worry about that. You say you're on a budget -- don't waste your money on plywood when 25¢ per square foot gypsum wall board will do the trick (even better).

(and I checked with local ordinance, for the minimal changes I am doing, NY state does not require a permit to replace the interior skin of a wall, i.e. removing plaster and adding sheetrock. )

That's great! But is that true even when it is a party wall (shared with a neighbor)?

--Keith

So, I doubled the amount of insulation in the wall. And I actually thought the opposite of the plywood. But given the material gypsum is made from, I understand why. Now the only question is how much gypsum to use: Do I use 3 pieces of 5/8" board, or two 1" thick pieces for that layer? I'm sure if I really wanted to go nuts, I could add a layer of neoprene somewhere too. I added the updated picture with the 3 layers option.

Acoustical caulk is not glue. You need to use screws as well.

Oh, you mean those twisty things that go into walls and things to hold them together? They usually gots a plus or a minus sign on the top right?

Although I am liking the glue idea. No screws would reduce vibrations to the studs, right? Is there a specific acoustic glue to recommend? What's the pros and cons of glueing. I'll search more on that like you said (so much to get through!).

I'll be searching more for the mass-air-mass equation too. Thanks!

Note the added "future angled speaker wall" image I added. That will be a future upgrade to the wall when I install real speakers. For now I can use a flat wall with padding, but I do plan on adding the 15 degree angles in the front.

[and the party wall is still interior with both buildings sharing the substructure making it really all one long building, so I guess it doesn't matter.]

=flynn

flynn wrote:I'm sure if I really wanted to go nuts, I could add a layer of neoprene somewhere too. I added the updated picture with the 3 layers option.

I'm glad you said that, because it made me look at your drawing more closely. You don't have any R.C.! So, yes, you do need something to decouple the new inner leaf from the studs and outer leaf. R.C. is the tool for that.

Acoustical caulk is not glue. You need to use screws as well.

Oh, you mean those twisty things that go into walls and things to hold them together? They usually gots a plus or a minus sign on the top right?

Cute!

Although I am liking the glue idea. No screws would reduce vibrations to the studs, right?

No, resilient channel will do this.

I'll be searching more for the mass-air-mass equation too. Thanks!

Yes, please do. Learn all you can by following the stickies on this forum.

[and the party wall is still interior with both buildings sharing the substructure making it really all one long building, so I guess it doesn't matter.]

Not sure I follow that...

Hmmmm, lots to consider here... including how much I really care about a place I won't be in a couple years! [I am a crazy audiophile!]

You can see the new attachments the general layout of what I'm working with. The first pic is my plan, the 2nd, my hood, and the third, my living rm and studio layouts.

Did more reading up on RC (Resilient Channel). That was EXACTLY what I was thinking about, thank you, Keith.

I found an old thread that talks about FAQs and everything about the whole drywall mounting and insulation issue:
http://www.johnlsayers.com/phpBB2/viewtopic.php?t=598

I also found another great page that talks good layman-speak about Resilient Channel and what it's for, benefits, including the company's own product, ect...:
http://soundproofing.org/infopages/channel.htm

In that 1st forum link, Steve talks about the materials used on both leaves (sides) of the stud being incongruent in frequency/thickness to eliminate/reduce transmission of vibration:

3. This double leaf wall should almost NEVER have exactly the same construction on both sides - a wall transmits sound (bad) more efficiently at its RESONANT frequency. If both leaves of your wall are identical, then so will their resonant frequencies be identical. If that frequency is, say, 44 hZ, then that frequency will pass right through the wall with MUCH less attenuation than other frequencies. Not good.

He also wrote earlier, that when layering gypsum according to poker rules (answering my earlier question):

2. Two different thicknesses of wallboard beats two of the same size for mid/upper frequencies, two thicker panels does better at low frequencies.

4. Fastening a second layer of wallboard to a first layer, when the first is mounted on RC or STEEL studs, should be done with screws through the first layer and into the RC or (steel)stud ONLY - if these screws touch WOOD studs the isolation of the wall will be reduced by as much as 9-10 dB. The STEEL studs are flexible enough not to cause a loss in performance.

NOTE THE 1st ATTACHEMENT:
I am essentially working with a Double Leaf wall with differentiating layer construction on each leaf. OLD school Plaster-and-Lathe wall on the neighbors side (pink) with an STC of about 42 (my gu-esstimate from an average on numbers I found at http://www.sizes.com/units/sound_transm ... ss_stc.htm).

I then add all my internal acoustical absorbtion efforts inside my wall (the Roxul). The Mineral Wool adds approx 5-9 STC points depending on usage, and I'm alternating placement for minimal fire routing. Then comes the layer (or rails) of RC.

Note the 1st picture here again - Here you'll see the bottom section has fewer mountings of Channel. I eliminated the one RC in the lower section of the new wall in accordance to how I believe the rules depicted by Steve in the same FAQ:

3. Low frequency attenuation is improved by NOT having RC, by increasing mass, increasing air gap between leaves, and increasing stiffness.

I believe this should help absorb my lower freqs, and using different drywall sizes and more insulation, since the sub will be installed under the desk area on that level. Did I get this right, or am I mis-understanding this too?

Now, I'll then attach the 3/4" drywall onto the RC on the upper part of the wall, and a 1" drywall on the lower wall (hanging the drywall horizontally) for the lower freqs. I'm also playing with the idea of adding a layer of neoprene foam on top of each channel to add more absorbtion. Hmmm...?

[Note: to observe NOT screwing over framed channel mounts over framing to avoid "canceling out" the floating resilient channel.]

Next, (this is where I'm getting creative), I'm going out on a limb and suggest caulking/glueing a layer of neoprene to the first drywall layer, then attach the thinner drywall to neoprene with caulk/glue. This would give another layer of insulation that would be part of, or glued to the first drywall layer, with the neoprene between the two drywall, adding absorbtion with Steve's recommendation of using two different size drywall when layering, attaching the two pieces of 5/8" drywall vertically to eliminate seems. The glued layers would act as one reducing resonance, right?

APARTMENT BUILDING CONSTRUCTION....
Oh. Check out this picture of my block (2nd Pic). Shows you right where I am on the block (red Outline is the apartment, yellow is the entire, congruent structure). The wall I'm working on is THICK red. NOW you may understand what I'm dealing with. This picture sees my side of the street facing North. The wall I'm dealing with is about two rooms deep of the forward exterior wall facing West. The wall pictured (2nd) is facing South.

Quote:
[and the party wall is still interior with both buildings sharing the substructure making it really all one long building, so I guess it doesn't matter.]
Not sure I follow that...

Now see the 3rd picture. Again, thick red wall is what I'm working with. This should give you a better idea of layout between the neighbor, my living room and Studio. The thick red wall is the party wall we're discussing. Essentially, the yellow outline is all the same building.

No, there is no dividing wall between the living room and studio. There is a walkway behind my seat, and an open window sill to the left. I have automated shades for all windows coming soon.

flynn wrote:Note the 1st picture here again - Here you'll see the bottom section has fewer mountings of Channel. I eliminated the one RC in the lower section of the new wall in accordance to how I believe the rules depicted by Steve in the same FAQ:

3. Low frequency attenuation is improved by NOT having RC, by increasing mass, increasing air gap between leaves, and increasing stiffness.

I believe this should help absorb my lower freqs, and using different drywall sizes and more insulation, since the sub will be installed under the desk area on that level. Did I get this right, or am I mis-understanding this too?

Yes, you are misunderstanding this. "Lower frequencies" does not refer to "lower to the ground" -- it refers to low frequency (bass). You do NOT want to have different thicknesses of insulation or different RC spacing in the same wall.

When Steve talked about "not using RC for low frequency isolation," he meant forgetting about using RC in a single wall frame and, instead, having two separate wall frames, with as wide of a gap between them as you can reasonably afford.

We're assuming you are not able to build separate wall frames parallel to the existing walls, due to the additional expense and (perhaps most importantly) the loss of square footage. Although RC is inferior to double wall frames, sometimes practicality takes over.

You also don't need Neoprene in the walls if you're using RC. The purpose of RC is to minimize/eliminate structure-borne flanking. I think it's safe to say that adding Neoprene to your mix will worsen performance.

The rest of your comments and drawings are pretty irrelevant IMHO until you reach an understanding of these fundamentals and can redo the drawings to conform with those realities.

Congratulations -- I believe you have inched yourself up to #17 on the Stages of Soundproofing Enlightenment!

--Keith

Rule #1 (in this case) - please do not EVER visit "supersound-SPOOFING.com" again - they have NO IDEA what actually works, will sell you TWICE as much "snake oil" as you need, and will charge you more than you should pay. I have no affiliation whatever with that site, good or bad; I'm only trying to save you grief.

Glue - be very careful here, some types will help (search the studiotips site for "green glue" or "GG" - but be aware that even this glue is no replacement for fasteners. It's main purpose is to act as a CLD (Constrained Layer Damping) between two layers of drywall, in all likelihood doing as much for damping as cavity insulation.

Speaking of which, for inside-the-wall insulation be very careful what density of mineral wool you buy; heavier than 3 PCF (48 kG/m^3) will "short out" between leaves if you try to compress it. Better to either use standard fiberglass batts (unfaced for interior walls) or a combination of the mineral wool batts and enough of the "fluffy stuff" to lightly compress.

Using heavier insulation in a wall will almost assuredly cause a "triple leaf" effect; better midrange TL, at a cost of WORSE LOW frequency TL.

Not sure from your drawings, but if your new and old frames are touching you'll lose a LOT of isolation. You need a space between frames to avoid flanking.

"AIR GAP" includes, as Keith mentioned, ALL the distance from one mass to the other - so if you have 3.5" stud frames separated by one inch and mass on the outer side of each frame, whether filled with insulation or NOT your "air gap" is 3.5" + 3.5" + 1", or 8" total. In actual practice, the results will be slightly worse than calculated because the frame members WILL slightly reduce the "effective" air gap, but not by much.

I'm more than a little concerned about your floor intentions though; do you know how the existing floor is built, and what its load capacity is? If not, it's time to find out BEFORE you help support your local undertaker... Steve

Heh, Sharward you so funny.

"Lower frequencies" does not refer to "lower to the ground" -- it refers to low frequency (bass).

That's funny. You actually thought I meant lower in placement. Incidently, I was half-meanng that due to where I'm placing speakers - which is why I placed the thicker wallboard more near the sub's placement. Lower. Hehehe. That's funny.

Steve, the studs that are in the drawing are all existing. I made the wrong assessment of your notes by eliminating the RC in the bottom on the structure on this wall, and the insulation. Keith cleared that up explaining the double wall concept. Hehheheeee.

I would have to add another wall of framing to those exisiting to create a double wall. The only problem is my space is VERY limited I was hoping to "get away" with using the RC. The insulation I have now is Roxul SAB. It's not the really dense stuff. I just got that because of my neighbor's fire, but I can switch to the other standard batting.

And no, due to very limited space, a double framed wall would be ideal, but that really is more than I want to do, and I realized I'm getting too involved with the neoprene idea.

LOAD CAPACITY: I understand your concern, I had the same thought myself when I moved in and started my project. Since I've been opening walls and running low-voltage wiring, lighting and Cat5, I've seen alot of the structure of these walls and floors. The building has a bit of a center sag, but the walls are all very solid. There are alot of 4x6 rough timbers in these walls (img 1). I've found the floors have been at the minimum 4x8 joists. However, I will ask the landlord if he's knows load capacity for the room.

Let's get back to that practicality thing. My one main intention I want to do, is what I stated before: Since I don't own the apartment, I want to do as little as necessary to keep down the complaints. I'm just happy to be able to make the wiring and wallboard changes I've been able to make. So, taking the last comments, I made this change:

Two pieces of wallboard, one 3/4" and the outer 5/8" mounted on RC (using the mounting rules Steve lays out in the FAQ link from above - still considering the GG option), over 8" of standard batting insulation. Would this be sufficient effort for the wall at hand?

I hate to say it, but yes, I'm doing this cheap and dirty. I'm only trying to be courteous for the neighbor's sake, which is why I opened the wall to begin with, I knew it had no insulation. I know this studio will not be perfect, it's more for my convenience of having the editing space during the day and the laws permit certain " noise tolerances" during day hours. I just love the fact that the landlord will let me do any of this!

If I owned the apartment, my budgeting would be very different, and include an architect and an acoustician (and most likely a large demolitian crew complete with wrecking ball)!

No need to switch the insulation, the SAFB's are fine if you already have them. Standard household fiberglass insulation seems to only lower TL by maybe a couple of dB, so in most cases it's not worth the extra expense/time trying to find the higher density stuff for inside the wall.

RC - make sure it really IS RC, and not "hat channel" -

http://www.recording.org/ftopict-22469.html

Other than that, looks like your plan will do as much as is practical in your situation; make sure everything is hermetically sealed (acousic caulk) at each layer. someone at another board posted an excellent mail order price on OSI 175 caulk if you can't find it locally -

http://www.toolup.com/powertools/id/SC1 ... _(NEW).htm

You'll get about 40 feet of linear 3/8" bead per 29 oz tube, you can do the math... Steve

Got this link from those posts on Resilient Channel. Hope this one doesn't suck too, Steve.

http://www.pac-intl.com/rc_update_12-02.html

Thank you for the feedback, btw...

=flynn