Isolation Booth: Insulation Questions

[Jack Russell]

Well, yes, I'm still slowly constructing my studio in my basement. I'm just about done with the wiring, and so now I turn to insulation...

I have an isolation booth, in which I will be doing vocals and guitars, or perhaps some other quieter recording. Dimensions are about 5 x 6 x 7 x 6.5 (with an angled wall). For isolating sound, I'm reading that the best approach is to position 703 panels on the outside of the walls. Is this right? If so, should i just put regular 3.5 inch insulation on the inside of the walls, or some other material? Rockwool?

Yes, friends, budget IS an issue as always...

 

[seismetr0n]

im not sure of the cost of rockwool, but blown-in cellulose is pretty cheap and effective, unfortunately, to have the wet-mix blown in youll need a contractor, it should still be cheap, and way better then fiberglass..

gl

 

[chris-from-ky]

Jack,
I'd suggest using your standard paper-backed "fluffy" insulation for the stud wall cavity. Then at least 2" OC 703 or Mineral Wool for the interior walls (covered by fabric of course).

Don't fool with the blown in crap. It's like why screw with packing peanuts when they make BUBBLE WRAP!!!! Get it?

 

[Jack Russell]

Thanks for the tips, guys.

I know there is a thread on this somewhere, but where can I buy 2" 703? I'm lazy and I don't want to search.

 

[chris-from-ky]

www.sensiblesoundsolutions.com

Brian (Bpape) is a member here. Seems like a nice and knowledgeable person. I think he sells 2" board. I've never bought from him but, I try to support small business whenever I can. Good luck!

 

[chris-from-ky]

CRAP!! I forgot to check where you were from. www.insulationworld.com is based in VA and sells rockwool or mineral wool that is just as good as 703 and it's cheaper.

 

[Jack Russell]

Thanks very much, Chris.

Merry Christmas.

 

[chris-from-ky]

Merry Christmas to you as well!!

 

[RICK FITZPATRICK]

For isolating sound, I'm reading that the best approach is to position 703 panels on the outside of the walls. Is this right?

NO!! Treatment products do absolutely nothing for isolation. Decoupled MASS is your only option. In this regard, a MASS AIR MASS, two leaf assembly with one leaf decoupled is your best bang for buck technique for increasing transmission loss. The bigger the airgap, and the more mass the better. For instance, for single wall construction, use staggered stud construction OR use Resiliant channel or Risc isolation clips mounted to a single wall framing assembly to mount the vocal booth INTERIOR drywall(walls and ceiling)to. Preferrably 2 or more layers of 5/8" gyp bd(drywall). A decoupled(floating between walls)floor platform is wise as well, with a 1/4" gap between the interior drywall and the finish flooring of the booth. Stuff foam backing rod in the gap and caulk, as well as overlaping and caulking all corner joints. Use a solid core door with a layer of 3/4" MDF glued and screwed to both faces. Custom make door jamb to match wall thickness, with a decoupling joint in the jamb. Mount DOUBLE door seals. But now that you've AIRPROOFED the booth, you have to penetrate the envelopes with ventilation supply and return ducting/registers. If you get this far, give me a holla and I'll post some drawings of stud cavity plenums. For insulation between the leafs(in stud cavities)


Or you could build double wall construction. Same interior drywall choice. Same insulation. For double wall, I'd build the walls ON a floating platform. Which can be floated by neoprene pucks or fiberglass isolators. Just depends on your overall isolation requirements.
As far as INTERIOR treatment goes, use 3 or 4" rigid fiberglass or mineral wool such as rockwool, covered with fabric. I would suggest planning all this on paper first. Flying by the seat of your pants is for barnstormers, not iso construction. Especially for the door jamb decoupling joint and and fabric fastening details/air plenum grills etc. Once you draw EVERY detail to scale, you won't run into problems as you build. It's impossible to see how everything is SUPPOSED to fit unless you see it before hand and KNOW what you are using. Otherwise, I guarantee you will have problems with afterthefact retrofits.
fitZ

 

[RICK FITZPATRICK]

I'm lazy and I don't want to search.

If you're too lazy to search, I guess building is out of the question huh?

 

[Jack Russell]

If you're too lazy to search, I guess building is out of the question huh?

O.k. o.k., you got me. But I'm only lazy until Jan 3. Then I become energized again.


and...For the prick (whomever it was) who flammed me in REP :

Merry Christmas to you too, asshole.

 

[Jack Russell]

But now that you've AIRPROOFED the booth, you have to penetrate the envelopes with ventilation supply and return ducting/registers.

Hmmmm....has anyone out there had trouble with their vocalist choking for air inside these airtight coffins? Human beings do need oxygen to live, you know.

Once you run in an air duct (and return vent) havent' you pretty much killed your isolation that you've painstakingly constructed?

 

[chris-from-ky]

Hi Jack!

By breaking into the airtight booth with vents for supply and return, you aren't necessarily defeating the purpose for all that work. The only sound to come in through the ducts would be mechanical noise from the a/c and the sound of forced air. By properly sealing the openings, using slow air in big ducts, and what I call baffle boxes, you can keep such noise at bay and get the proper isolation you're looking for and keep your vocalist alive! It's more than likely overkill for a good deal of home studios, but for those with the desire, money, and clientel to afford such a thing, it's feasible and useful.

 

[RICK FITZPATRICK]

Once you run in an air duct (and return vent) havent' you pretty much killed your isolation that you've painstakingly constructed?

What do you think they do in real studios? Usually the HVAC system is designed to meet an NC rating. If you have 65db room, plenums with silencers, ducts with 703 lining and noisless registers are used. Depending on the NC criteria, even ducts and plenums may be built with the SAME transmission loss rating as the room envelope assemblies. Plus, high volume, low velocity fans ar used with oversized ductwork.
For a high performance isolation vocal booth, yes, you must penetrate the exterior and interior envelopes. But they penetrate at DIFFERENT places to offset the penetrations.
This means plenums or a duct of some type must run in the stud cavity to connect the two openings. And supply/return ducts need at LEAST 2 90 degree bends in the runs from fan enclosures to the booth.
As far as breathing is concerned. Its your call. If you want a leaky booth so you don't have to deal with the air supply issue, so be it. You will also have a flanking path for sound through the leaks. It all just depends on WHY you are building a booth, and how much isolation you REALLY want. In the case of high spl instruments being recorded at the same time vocals are being recorded, if you don't want bleedthrough, then YES, you need a ventilation system whereby it DOESN"T become a flanking path, with a booth assembly with a high transmission loss rating. Although, from what I've seen here most HR people simply want to record vocals dry, and arn't that concerned with high performance isolation. In fact, blankets and a closet full of cloths are the
average HR enthusiasts vocal booth of choice. Like I said, it just depends on your needs.
fitZ

 

[punkin]

That Rick...he know what he's talkin' 'bout.

 

[Jack Russell]

What do you think they do in real studios? Usually the HVAC system is designed to meet an NC rating. If you have 65db room, plenums with silencers, ducts with 703 lining and noisless registers are used. Depending on the NC criteria, even ducts and plenums may be built with the SAME transmission loss rating as the room envelope assemblies. Plus, high volume, low velocity fans ar used with oversized ductwork.
For a high performance isolation vocal booth, yes, you must penetrate the exterior and interior envelopes. But they penetrate at DIFFERENT places to offset the penetrations.
This means plenums or a duct of some type must run in the stud cavity to connect the two openings. And supply/return ducts need at LEAST 2 90 degree bends in the runs from fan enclosures to the booth.
As far as breathing is concerned. Its your call. If you want a leaky booth so you don't have to deal with the air supply issue, so be it. You will also have a flanking path for sound through the leaks. It all just depends on WHY you are building a booth, and how much isolation you REALLY want. In the case of high spl instruments being recorded at the same time vocals are being recorded, if you don't want bleedthrough, then YES, you need a ventilation system whereby it DOESN"T become a flanking path, with a booth assembly with a high transmission loss rating. Although, from what I've seen here most HR people simply want to record vocals dry, and arn't that concerned with high performance isolation. In fact, blankets and a closet full of cloths are the
average HR enthusiasts vocal booth of choice. Like I said, it just depends on your needs.
fitZ

Well said, fitz.
In my particular case, you are right: my main objective is to record dry vocals. Or the room would be used to do an acoustic guitar track, or perhaps a violin in a rare moment. Not much else. My HVAC is about 15 feet away from the Voc booth. So, it seems to me that whatever duct I run to it would let the mechanical sound in, due to the proximity. This is all in a basement.

Besides the HVAC, the only sound that I can imagine that I'd have to contend with to isolate the booth away from would be the sound of my PC in the mixing room, about 6 feet away. My studio is in a basement, out in the country, BTW.

And you are absolutely right: this is a part time project studio, not a real studio.

 

[RICK FITZPATRICK]

Hello Jack. Well, what can I say. The point of most of my replies is to tell the truth. It's the knowlege that counts. The better armed you are, the better you can adjust your prioritys. Man, I know I've made some pretty tough reality checks lately in regards to my studio. I completely threw out the iso stuff. My studio is relatively quiet. Its out in the country. Its for my enjoyment only. No clients or recordings that will reach other peoples ears. So why the hell worry about it. . The problem is when people THINK they need something, spend a fortune to get it, and then realize this iso stuff is NOT intuitive and they;ve wasted a bunch of time and money. THAT is why I try to enlighten people with what I "think" I know. If I can save someone from that by simply teling them the truth, then I've fullfilled my obligation as a member here. Anyway, good luck, and if you have other questions that I can help with, just holla. BTW, don't let the CAVE get to ya. Or judge me by my replys there. I just use it to vent instead of here.
fitZ

 

[Jack Russell]

No problemo, Fitz. I enjoy all your rants in the cave. And I am always only 50% serious there anyway. You have to figure out which half of me is serious and which half is silly. hahaha.

one last moronic question:

what is 'iso'?

 

[RICK FITZPATRICK]

what is 'iso'?

Oops. Sorry. Its short for "isolation" or "soundproof".