952 Studios Construction!

[eightamrock]

Sorry to be rather late with this!

As Glenn pointed out, there are things you can do to help deal with it. Which it looks like you already did!

It will create a 3-leaf system, yes... but the real questions are then: How bad that would be? and Can you compensate?
There are equations for calculating resonant frequencies of 3-leaf systems, but they are a little complicated ( ), so maybe not really useful.
If you have a large air path above that "middle-leaf" and below the roof deck itself, up through the eaves then out through a ridge vent (possibly required by code, but a good idea anyway), that would help to mitigate the situation, a little. If the roof deck itself "leaks" air, such as through an old-fashioned tiled, shingled, or slate roof, that helps too. Insulation in that gap (but not filling it, due to the need for the air path) also helps a little. Making that gap as large as possible (oversize rafters, or spacers under the rafter for the middle-leaf) also helps. A large air gap between the middle and inner leaf, completely filled with porous insulation (eg, "pink fluffy" fiberglass insulation, or mineral wool, in both cases of suitable density) will also make a difference. Adding extra mass to the middle leaf and/or inner leaf also helps.
So there's several things you can do to improve isolation if you are forced to use a 3-leaf system. You can do the math if you want to figure out f it is enough, but be warned: it's complicated!
Reasonable rules of thumb: increase your air total gaps by at least 50% above what it would have been for the 2-leaf, and double the total mass on the leaves if possible (or at least increase it as much as the structure can safely handle).
Basic question underlying all this: How much isolation do you need (in decibels), and what's the lowest frequency you need to isolate? Knowing those two can help you make better decisions.


- Stuart -

Going back to this topic as I am growing concerned. Rather than packing the roof rafters with rigid foam, drywall, and rockwool, and potentially creating that 3rd leaf, would it be easier to simply add some rockwool up there, then add a third layer of drywall on the iso clips? Im worried that only 1" of space isnt going to create enough air flow to vent the soffit to the ridge vent. If I just put rockwool into the rafters, that will give me several inches of space for air to flow up and out. Then I add some additional mass to the inner leaf to compensate....

Thoughts?

[gullfo]

you could do that but i would add the clips to create another (small) air gap on the inner mass layer. that said, i believe 1" is the minimum needed to create the soffit-vent flow needed.

[eightamrock]

Hey Guys, quick one for you. Im ordering my wall plates and cabling. My plan is to have 8 channel cable runs (4 for live room, 1 for iso) all installed within conduit in the wall so I can add/remove cabling when needed.

Can I use Mogami W2932 or Gepco GA61808GFC for in wall installation? Ive read a lot of review and forum posts, everyone seems to think they are both great cables and I cant go wrong with either, but I wanted your opinion. The runs between rooms are fairly short, less than 50ft, but I just want to make sure I get the right stuff (shielding, AWG, etc) for a permanent installation that will be headache free.

Also some folks use quadcore wire for mics, is this necessary?

Any thoughts here would be great.

[Soundman2020]

I've had good experience with Mogami. Never tried Gepo, so I can't comment on that. Canare is another good one I recommend.

Not so sure about quadcore, to be honest.

What I would suggest, is that you run way too many cables while you are doing this! If you think you'll need 8 channels, run 12 or 16. If you think you'll only need balanced XLR, then run some unbalanced line-level cables too. And also run cables that you DIDN'T think of: HDMI, Cat6 UTP (Etherent) and also STP, CCTV if you have that, alarm wiring, maybe even plain old telephone ("POTS"). And run extra ones of all of those: if you think you might need one Ethernet cable, run 4. Even run extra electrical wiring to each outlet, just in case.

You might think right now "I'll never need that!" but run it anyway. Installing cable now and never using it is a hell of a lot cheaper and easier than trying to install it down the line, when the studio is finished. "Wasting" 50 bucks on an unused cable sort of beats ripping holes in your walls in the future, or losing a customer because you were one mic channel short of what he needed...

I can pretty much guarantee you that the day will come when you think: "Ya know, it would be really cool to have a ZZZZZ in the other room, connected back here! And wouldn't ya know! I already have a spare cable for that!". Or when one of your eight XLR runs will suddenly go dead, and you'll have a spare in place to take over...

Think big!

(You'll thank me later... )

- Stuart -

[gullfo]

yeah the conduit is good to allow future pulls. my recommendation is go with all hyper-twisted fully shielded digital cables. and terminate with RJ45. with each 258 block RJ45 termination you could have 2 or 3 XLR (depending on sharing a common ground or not) plus you're digital ready. a couple of plenum-type cables per room should be enough to address analog and digital needs. then using adapters as required - HDMI, USB, Dante, etc etc. only thing i would add is pull a couple of optical lines when you're ready for digital terminations.

[eightamrock]

Thanks for all the wiring tips. Redco just made a boat load of money off of me

[eightamrock]

Well that was fast!

[Soundman2020]

Those look real nice!

(Now comes the 'fun' part: wiring.... )

- Stuart -

[eightamrock]

Ok guys, I need some advice.

As you know, I am dealing with the new ceiling issue that I hadn't anticipated when I filed the original plans. We were required to add collar ties in addition to the ridge straps to get the ceiling to code. The collar ties bring a horizontal plane at the peak of my ceiling at about 13.5' that is roughly 5-6 feet wide and 8ish feet long. I had adjusted my plan to use isomax clips and hat channel to decouple the ceiling but I am wondering if I should just continue with the original plan of building my inner hip ceiling and just sacrificing the additional 10 inches of head room.

My rationale for the isoclip ceiling was to keep as much overhead as possible, but it will sacrifice a bit of isolation. My question for the pros is would it be better to just stick with the inner fully decoupled ceiling? Will I notice the loss of 1' of ceiling height in day to day operations of the live room? Another benefit I see is that to make the ceiling work I can just change the pitch of the celing so there would be no flat spot at the peak, all 3 ceiling segments would be angled so there would be no slap from floor to ceiling anywhere. I feel like this would greatly reduce my need for a central cloud in the live room to control reflections.

Im a bit torn, could use some advice....

[Soundman2020]

A couple of quick questions (which you probably already answered earlier in the thread but I'm a bit short on time right now to go looking for them again):

What is your goal for isolation! (How many decibels of "transmission loss" do you want from your room?)
What is the purpose of the room, mostly?
What would the ceiling height be if you just do it flat, without vaulting it up close to the collar ties?

In general, ceiling height is a very good thing, especially for tracking rooms / rehearsal spaces / live rooms. From that point of view, my advice would be to keep it if you possibly can (especially if you can get another foot of it!). For example, most instruments just sound so much better in a room with a higher ceiling. In the case of drums, its very important. Trying to track drums in a room with a low ceiling just sounds dull and lifeless, and you'll likely get comb filtering on your overhead mics. With a high ceiling, that isn't an issue, and the drums will sound a whole lot cleaner and more lively.

However, if very high isolation is critical, then maybe you would need to sacrifice some height to get it. For example, if too much noise outside could bring along the cops with an order to shut you down, then sacrificing a few inches would be a good thing!

On the other, other OTHER hand(!), increasing isolation is usually possible; an extra layer of drywall on your ceiling, and complete filling of the cavity with the most suitable insulation can gain you several additional dB of isolation. Building your ceiling "inside out" can increase ceiling height considerably, at the cost of only a little isolation.

Isolation clips don't necessarily have to sacrifice a lot of isolation: As with all things in studio building, there are "better" ones that will give you more isolation (usually at a higher price), and "not so good" ones that are cheaper but compromise on isolation. Nearly as important as the clips themselves, is using them right! Following the manufacturer's instructions carefully, using the best drywall, and sealing the hell out of it, are all very important.

So there are certainly pros and cons, but the answer depends on your answers to the key questions; How much isolation do you need? How critical is ceiling height for your room?


- Stuart -

[eightamrock]

Source of the post So there are certainly pros and cons, but the answer depends on your answers to the key questions; How much isolation do you need? How critical is ceiling height for your room?

Thanks for the response as always, Stuart. Even with having planned, replanned, redrawn, and redesigned several times you always end up with these mid-project choices to make.

Let me try to answer your Q's one at a time.

1. How much isolation do I need? My main concern is environmental noise coming in, particularly suburban landscaping machines. I took a reading inside my existing structure with the door shut and no real isolation applied yet and I got a 70 DBC value. So at that volume, the mowers etc were clearly audible and would definitely bleed into my mics. I need to reduce that down to something inaudible. Mostly in the lower bands, you can "feel it" more than anything.

2. The room will be used for tracking drums and live instruments primarily. Im less concerned with sound getting out than I am with getting good clean sound without the neighborhood lawnmower gang mucking up my takes. Id also like to be able to record at night, outside ambient is about 40DBC at night. So the noise INSIDE the space needs to come down to that level on the outside. within 25 ft, which is where the first floor window to my house is and about 300 feet from my neighbor.

3. I bought isomax clips https://kineticsnoise.com/isomax/sound-isolation-clips at Glenns advice. I have used the green glue company whisper clips in the past with great success, these seem to perform a bit better on paper.

4. I wouldnt say my project needs to be super HIGH isolation, Im not next to a highway or anything but daytime ambient noise is a thing here and Id like to keep it out. The most isolation I want to have is between my live and control room, I think that is mostly covered as my rooms are fully decoupled from each other.

5.
a. Flat ceiling in the live room would be 9' 8" exactly.
b. Vaulted with iso clips on existing rafters is 9' 8" to 13' 1".
c. Framing a vaulted inner leaf would be 9'8" to 12' 4"

Does this help? Based on your response I "think" I should stick with the isoclip solution and get maximum ceiling height. However, I could do an inside out ceiling on the inner leaf, and not lose the whole foot of space, more like 3-4".

[Soundman2020]

Quick response....

1. If you have 70 dBC outside and need "inaudible" inside, then around 40 dB of isolation will do the trick. That would put the levels inside down around 30-ish dBC, which should be decent for most tracking needs (maybe not for Foley work!). I'd still shoot for 50 isolation where possible, to be safe, but as long as you are getting 40 you should have no more issues with rampant armies of lawnmowers invading your drum mics! 40 is certainly do-able with what you have, and 50 is perhaps within reach, with a bit of luck.

2. Drums do like high ceilings!

3. Both of those clips are among "the good guys". Either one is a decent choice.

4. Decoupling rooms is great, but if your #1 priority is inbound noise in the tracking room, then the tracking room deserves all the care you can possibly give it. Decoupling it from the entire rest of the building would be a good start. Sealing it as though your life depended on it would be a good second (including windows and doors). And lots of mass on your leaves (including windows and doors!) with good insulation completely filling the cavities would be the third.

5. "Vaulted with iso clips on existing rafters is 9' 8" to 13' 1". " Hell yeah! a 13 foot ceiling (or close) for drums would be very nice to have.
"c. Framing a vaulted inner leaf would be 9'8" to 12' 4" " Even 12'4" is way better than only 9' 8" Instruments do like room height, and room volume.

So my advice would be to go for the highest ceiling you can get, put as much mass on it as you can (check the specs for your clips) to see how much they can handle safely, seal it incredibly well.

Have you considered the third option? An "inside out" ceiling would probably get you the height without compromising the isolation...


- Stuart -

[eightamrock]

Source of the post Quick response....

1. If you have 70 dBC outside and need "inaudible" inside, then around 40 dB of isolation will do the trick. That would put the levels inside down around 30-ish dBC, which should be decent for most tracking needs (maybe not for Foley work!). I'd still shoot for 50 isolation where possible, to be safe, but as long as you are getting 40 you should have no more issues with rampant armies of lawnmowers invading your drum mics! 40 is certainly do-able with what you have, and 50 is perhaps within reach, with a bit of luck.

2. Drums do like high ceilings!

3. Both of those clips are among "the good guys". Either one is a decent choice.

4. Decoupling rooms is great, but if your #1 priority is inbound noise in the tracking room, then the tracking room deserves all the care you can possibly give it. Decoupling it from the entire rest of the building would be a good start. Sealing it as though your life depended on it would be a good second (including windows and doors). And lots of mass on your leaves (including windows and doors!) with good insulation completely filling the cavities would be the third.

5. "Vaulted with iso clips on existing rafters is 9' 8" to 13' 1". " Hell yeah! a 13 foot ceiling (or close) for drums would be very nice to have.
"c. Framing a vaulted inner leaf would be 9'8" to 12' 4" " Even 12'4" is way better than only 9' 8" Instruments do like room height, and room volume.

So my advice would be to go for the highest ceiling you can get, put as much mass on it as you can (check the specs for your clips) to see how much they can handle safely, seal it incredibly well.

Have you considered the third option? An "inside out" ceiling would probably get you the height without compromising the isolation...


- Stuart -

Thanks again, I think I will go for max ceiling height. Ive already purchased all the materials to do the isomax clip solution on the existing rafters so, I can just stick to the plan.

The inside out ceiling is interesting, I may do this in my control room which is only 9x17x13 I have 2x8s overhead so an additional 7" of dampened ceiling height would definitely help!

[Soundman2020]

Source of the post The inside out ceiling is interesting, I may do this in my control room which is only 9x17x13 I have 2x8s overhead so an additional 7" of dampened ceiling height would definitely help!

Right! It's 7" of "free" acoustic height. 17x13 is already a nice size, so getting a little extra height should make it fantastic. Did you try your dimensions on a room mode calculator? It's worth doing that, to make sure you aren't going to have serious modal issues.

- Stuart -

[eightamrock]

Source of the post Right! It's 7" of "free" acoustic height. 17x13 is already a nice size, so getting a little extra height should make it fantastic. Did you try your dimensions on a room mode calculator? It's worth doing that, to make sure you aren't going to have serious modal issues.

- Stuart -

I did look at it in amroc calculator: https://amcoustics.com/tools/amroc?l=17&w=13&h=9&ft=true&r60=0.6 I think it all looked pretty good, but admittedly Im not an expert. I just punched numbers until I got a ratio that was good for my space. The ratio is 1 : 1.44 : 1.89 pretty darn close to "Best ratio as per Louden 1 : 1.4 : 1.9". Maybe you can read it differently and say if Im missing something?