iso does this help rick?

[wangchung]

Just a Q/A new thead I touched on with rick. Any advice guys is greatly appreciated. I'm too long in the tooth to be doin vocals at 3am to keep my ambient noise down.

Q: Is this a one room studio or do you have a seperate control room?

A: Though I do all my tracking in one room, I do have a small bathroom and a kitchen area that I sometimes put a very tiny gtr amp in.

Q: Tell us what ALL the problems are with your vocal recording, and how you record(do you need to isolate live instruments from vocals for simultaneous recording)?

A: NOPE. Though that would be nice. everything, I D.I including kit. TD20/Boom theory. straight into my fairlight.

Q: What kind of ambient noise do you hear and or pick up on the mics?
Any low rumble?

A: Now yu talking. Yep, a definite low rumble that gets less into the night. I’m sure it’s the road.

Q: How and where do you set up the vocal mics presently?

A: in the main control room. u67/87

Q: Since environmental noise transmits into the studio, it works the opposite as well. Are you trying to keep studio sound from transmitting to the outside?

A: Nope

Q: Tell us ALL about the "concrete outbuilding", roof, ceiling, walls, doors, windows, HVAC, floor and partitions. Give us a size(interior dimensions-including height and description of interior wall type(drywall over concrete?) If so, is the drywall furred out?

A: Concrete block walls with a 4” cavity, foamed filled, plastered board and finished walls. 18’x9 aprox.
Ceiling is wood framed, with two 4”cavity segments filled with high dense rocwall and foam which is then wrapped in hi-dense cloth. (see pic attached)
6'6 slopping.
Floor is 8" reinforced concrete then concrete tiled and carpeted.

Q: What kind of music/instruments. Will vocalists need room for instruments like a guitar?

A: No, I think I could scam that one.

Q: Does the booth need to be disassembled for moving later or can it be built perminent?

A: Permanent

 

[RICK FITZPATRICK]

Hello wangchung. Ok, gotcha. Here is my opinion. Extremely low frequency rumble is usually transmitted from the road through the ground directly to the slab and concrete walls, and results in low frequency resonant decay in the room itself due to small room dimensions(room modes) and mass of walls lack of ability to absorb, causing reflection or low frequency buildup in corners, which in small rooms, wavelengths of low frequency occilation are longer than room dimensions, which results in a long low frequency RT-60 decay. RT-60 stands for the time it takes sound to decay 60db.

There are three possible RETROFIT improvements to your recording/mixing environment. Since this type of environmental noise is the most difficult to isolate from the interior, it requires MASSIVE amounts of bass trapping in the room itself(do a search on "SUPERCHUNKS), and or building an extremely DECOUPLED enclosure within the room...ie, a booth Not only that, but since this low frequency resonance/decay exists within the room, the assembly of the booth itself requires a "floated" ROOM WITHIN A ROOM design(decoupled inner envelope) with as much mass on each leaf and as much airgap as you have room to devote to it. Your biggest problem is room height. Since a "decoupled" inner envelope requires not only mass, but a total decoupling from the slab itself, given the height restrictions, this will present a problem with the FINISH height dimension in the booth as you are already at a minimum with the existing height.

Therefore, with this criteria in mind, let me suggest a few decoupling solutions. Depending on your budget, skills, time, NOISE DB PROFILE(how loud), recording IMPORTANCE etc.....

(1.) The first is simply building a floating box with ONE MASSIVE leaf on the exterior of the framing, utilizing the stud cavity for placing ABSORPTION material such as mineralwool (rockwool/ rigid fiberglass.) This would entail framing a floor assembly with a plywood bottom and placing this on fiberglass or neoprene isolation pads. Once completed, then laying a visqueen layer IN the cavities and FILLING with kiln dried sand and folding over the visqueen on top of the sand. Then lay a SUBFLOOR, either OSB, plywood or MDF and SCREWING/gluing it down. Frame the walls ON this platform. Shieth with either multiple drywall layers on the exterior, caulking all joints, taping and texturing, OR use one or two layers of MDF. Your CEILING would be the most difficult because of limited height restrictions. I would suggest framing and shiething it on the floor and lifting it into place and fastening from the inside. Mass is what you need though. This may be be good enough to prevent transmission of low frequency decay into the booth from inside the room. However, without measurements, calculations and testing, its IMPOSSIBLE to say from my standpoint. Thats the problem with these sort of scenarios. ONLY you can determine this.

(2.) Same scenario as above, only this time utilizing TWO leafs. Two existing walls can be used for two sides of the OUTER shell. However, this would still present HEIGHT problems. AND, it takes up more floor space, requires TWO doors(solid core) and the associated jambs and hardware, and STILL has height problems. Not to mention stepping UP into it. BTW, two doors in a booth is a CHORE, because of the limited floor space in the booth, BOTH doors must open OUTWARDS Needless to say, framing and detailing of the jambs and the associated seal between the two jambs can be awkward at best, impossible to the uninitiated or intution handicapped.

(3)As to the height problem, I know of a solution which requires some extreme labor and still has the associated ceiling and door problems But this all has to do with HOW SERIOUS YOUR RECORDING REQUIRES IT This idea is done in most high end world class studios, and a few home studios that I know of.
Here are some links to show the concept. Although yours would be MUCH simpler, this is the reality of REAL LOW FREQUENCY TRANSMISSION SOLUTIONS. Warning....extremely long threads

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2921&start=0&sid=a8030ad7d12626e9d0ccb560219c59b0

http://forum.studiotips.com/viewtopic.php?t=107


It involves CUTTING the slab, breaking and removing the existing block of concrete, digging out the soil, framing a concrete form, laying a visquene barrier, pouring a LOWERED support slab, REFRAMING a form to pour a FLOATING SLAB for the interior shell. Laying fiberglass isolators and dampening pad, which is the same as Pauls studio build. Much smaller scale though. Pouring the DECOUPLED Slab, and then building a TWO LEAF envelope with the exterior leaf decoupled from the interior leaf. This whole scenario DEMANDS planning, paying attention to detail, and a good insight into construction. And you still have to deal with the ceiling. Although, you MIGHT be able to do the same thing there, by cutting away a portion of the existing cieling/framing and reframe a higher area above the booth. That is, IF your roof/rafter framing allowed it.

Regardless of any solution, you also have to deal with ventilation. High transmission loss SOUNDPROOFING also means AIRPROOFING. A few minutes in a SEALED enclosure can be a real unpleasant experience. Heat generated by a light and a human being can quickly build up within. Not to mention FRESH AIR to breath. Singers really hate passing out

Anyway, hope this helps illuminate some of the problems and solutions. Give me a holla about what you think and we'll try to go from there.

One other thing. These are my OPINIONS, and are ALWAYS subject to EXPERT
scrutiny and correction. BTW, these drawings are for ILLUSTRATION only, and are by no means plans or comletely detailed assemblies, and are SUBJECT to local codes and permiting process by Building inspection departments. Proceed at your OWN risk.
fitZ

 

[wangchung]

Thanks man. much food for thought. Most of the work I do is in pre and post, which involves alot of bits and pieces being added to a final mix. This was never a problem when I was using the myriad of studios I had access to in the past, separation was never an issue. But I do find myself wanting to work more from home with all the problems that scenario throws up and with regards to the nuances of a mere rumble to contend with, I need to sit down and absorb (pun intended) the info you have taken the time to put forward. Again. many thanks Rick.

 

[knightfly]

If the rumble is your only problem and you're doing mainly vox, have you tried just kicking in the low cut filter? Just a thought... Steve

 

[RICK FITZPATRICK]

OMG! sheeeeezus!

 

[wangchung]

Rick. Had the room and it's subsequent corners, ceiling, walls etc spectrum analised by a very good friend of mine, who just happens to be Abbey roads acoustic engineer, on this fine noisy road evening (6pm for max road noise) and yep, we did roll off the low filter nightfly to have ours and your worst fears confirmed Rick. Crap loads of rebuilding and absobing technoligy to be had. We've opted on floating the iso with much digging and sand replacement to be undertaken. I'll post the pics accordingly. Just goes to show that when you want to work at home PROFESSIONALLY and be self contained, you really have to think long and hard about every step. I should know better

 

[RICK FITZPATRICK]

 

[knightfly]

Oh well, if ya don't try the easy stuff first sometimes you end up doing the hard stuff for no reason (other than extreme masochism :=)

My next question would be, how far down can you dig? If your ceiling is already only 6/6", and you need a floated floor with a m-s-m resonance low enough (about 7 hZ) to successfully isolate the full audio spectrum, it's gonna take about 15-16" to do that; 6" top slab, floated over another slab that's at least as thick as your existing one, then walls/ceiling to match the mass-air-mass performance of your floor, tight double-door sound lock, air handling that doesn't lose all you've worked for...

Given any thought to relocating somewhere quieter? (Again, trying to examine less painful alternatives) ... Steve

 

[wangchung]

He's decicide on a 10" dig out nightfly , with two partitioned layers of sand for the floor. He, like rick is convinced that the road is resonating the building which he feels is mostly a floor thang. As for the walls and ceiling, we're gonna put in yet another 4"cavity for the iso area, totaling three 4" layers. the last of which will also be filled with sand. (maybe he's a beach bum) My acoustic guy is insisting that a dense sand barrier is the answer. Who am I to argue .

 

[RICK FITZPATRICK]

As for the walls and ceiling, we're gonna put in yet another 4"cavity for the iso area, totaling three 4" layers. the last of which will also be filled with sand.

BAD idea. What you are talking about is creates MORE than two leafs, as you must contain the sand in the last layer, Thats two leafs in itself.
Not to mention the weight of the sand itself trying to push out at the bottom. Maybe with a layer of 3/4" MDF on each side of the stud, but still a bad idea. You are better off with ONE AIRGAP, as deep as possibe, with TWO LEAFS Of MASS, preferably with one leaf decoupled.(LIKE I DREW!!! Believe me.) The mass can be multiple layers of drywall or MDF, but drywall is MUCH cheaper. Different fabrication requirements though. Also, the airgap needs to be SEALED, and filled with batt type insulation.
One other thing. I don't have any idea of your building codes there, but to do this in ANY city in the US, your looking at permits. With double walls, especially if electrical is in any of them, there is no way to FIRESTOP the cavities as that would connect one leaf to the other. I have read of Permitted assemblies where the airgap is filled from leaf to leaf, 24" high with
fiberglass insulation. This acts as a fireblock. But I have no idea of your codes so don't quote me. No matter, hope this helps a bit more. Although, my disclaimer is in FULL FORCE at all times.

PS. Apparently you didn't see THIS on shellshocks thread.

 

[wangchung]

Aparently, I'm the one jumping the gun . that's what happens when you get too excited and don't understand the implications. (so he tells me) My man also suggested, in his ever so slightly arrogant manner, that I should stick to what I know best and let him do what he has been doing for 30+ years, unless that all I require is a fairly good responsive demo environment. Jeez! that put me in my place
The sand (apparently) is for floor only and the walls and ceiling are air cavitys of dry wall and heavy duty cloth. remember guys, these are quotes from a guy that is very proud of his accomplishments in his field, so I'm trying to put the right questions as naively as possible. Like being back at school. I don't want to piss him off too much, but when major surgery is suggested, I ask. Period. From my perspective It's a little daunting, trying to get a handle on the what and the whys. So, I bow to the master, because if anybody ever told me how to record and produce, I would have to rearrange their ego slightly too. So there goes my theory on thinking I had a basic understanding of the principles of accoustics.
Maybe he had a rough night?
As far as regs go Rick. Because the building could burn for years and not effect anyone else, they're not that concerned. That's the limies for yu