Adjacent walls

Michael Jones · Post by **Michael Jones** » Wed Apr 09, 2003 12:38 am

If someone could take a look at my floor plan here:
http://www.johnlsayers.com/Studio/Pages/Carriage.htm
and look at the adjacent walls between the Control Room and the Drum Room; See the space between the walls?
Would it be best to drywall that inside (between the walls) space? Or not?

If it gets drywalled, then I have to drywall it one of the walls before tilting up the adjacent one. So, I'm working to weather in the building so that if need be, I can do that.

If it doesn't need to be drywalled, then the space between the walls, next to the sliding glass doors, just gets a pannel pushed between them? So that you can't see between the walls?

Yes, no, maybe?

Green House · Post by **Green House** » Wed Apr 09, 2003 12:58 am

I was under the impression that with double wall construction you don't want to sheath both sides of both walls. STC is lowered with the additional barrier. I would drywall the inside of each room and leave exposed insulation in the airspace. This is convenient also because it will make the job easier.

Michael Jones · Post by **Michael Jones** » Wed Apr 09, 2003 1:27 am

Yeah, that's my understanding too, but in some places these walls are as much as 12" apart. With that kind of separation, does the theory still hold trrue?

knightfly · Post by **knightfly** » Wed Apr 09, 2003 3:32 am

Michael, even at that wall separation, the "2 leaves, one air space" thing would still apply. If the inner covering in each room is the 3-layer construction stated on Johns site for those walls also, you should have good isolation and a third leaf would only make it worse.

You might want to make one of the leaves (say, the one on the inside of the drum room) with different layers, to avoid both leaves having the same resonant frequency - Sjoko mentioned a construction he's had good results with here -

http://www.homerecording.com/bbs/showth ... adid=76374

Note Sjoko's comment about the "railway line" - if his wall would work there, it should be great for the lows from a drum kit. Maybe do the drum side that way, and the control room side your way - this would spread the resonant freq's and give better results than two leaves being the SAME, no matter WHICH construction chosen. Remember, the resonant frequency of a wall is the frequency that will come thru the loudest, so 2 DIFFERENT resonant wall leaves are better.

For the window surround, I'd use 2" 703 or Knauf all the way around, covering it with a dark cloth (preferably fire rated, or at least treated) - If you seal it against the frames all around with acoustic caulk, then the space between the walls will bleed off some of the sound coming thru the first layer of glass, acting as a wide-band absorber. This should improve the window performance as compared to using harder material in that location. (In either case, no contact between walls other than the acoustic caulk - not as important with compressed fiberglas, since I've seen isolators made with the stuff at kineticsnoise.com)

As to the window, I hope you're planning to follow the same two leaf idea - two panes of heavier (but different thickness), preferably laminated, glass will give better isolation than 4 panes of lighter glass. (Or even 4 panes of the SAME glass, for that matter)

Not sure by the plan, but I'm hoping you left enough room in the drum booth for vocalist to walk behind the kit? Otherwise, it could be kind of an irritant. (I know, where was my head BEFORE you got this far? Sorry, all I remember is that it was very dark, and smelly :=)

I hope this helps - it looks like you're going to have a really sweet setup there when it's done, way to go... Steve

Michael Jones · Post by **Michael Jones** » Wed Apr 09, 2003 11:22 am

Steve, thanks for the input, but I think you're misreading the plan. Those are not windows, but sliding glass doors. The doors I have picked out are 2 sets of double pane doors. They're exterior grade doors, and have 3/8" tempered glass on one side and 1/4" tempered glass on the other.

What prompted this whole thing was that I didn't think the inspector would allow a "non-drywalled wall", but I spoke to him today when he was over here inspecting the final copper for the plumbing.

He said it was fine to not drywall both sides, but that I would have to put a panel between the 2 walls so that you couldn't "see" between them. He said "...just don't let the distance between the 2 walls exceed the nailing schedule for the material to be used as the panel...".

So that means no more that 16" for 1/2" drywall. My widest wall gap is 15".

So this brings me to another delima: How to "decouple" the panell that has to go between the walls?

Be that as it may...
I was planning on doing a multilayered wall system consisting of 1/2" sheetrock|OSB|5/8" sheetrock on all the walls. But if I understand you correctly, you say that one wall should be varied so that it has a different resonate frequency? OK. I understand. What would you suggest?

OK, now on to the drum room:
I was planning on doing a raised platform for the drums, and having a rock wall behind that. I'll have the mason make the facade irregular by "pulling out" some rocks and "pushing in" others. Make sense?

So there's NO WAY you could walk behind the drummer.
But if you're doing a multi-track session why not just have the whole band, except the drummer, who remians in isolation, in the live room. Let them play, and pipe that into the drummers headphones, while you concentrate on really just getting a good drum sound. The live room take would really just be a scratch track, for the benefit of the drummer.

Then re-cut lead and harmony, with drums piped to them, and finally, cut vocals.

Anyway, what I'm getting at is that drums and finall vocals would never take place at the same time anyway. So why have the vocalist be able to walk behind the drums?

OK, now I'm rambling..........

Michael Jones · Post by **Michael Jones** » Wed Apr 09, 2003 11:52 am

Remember this plan?
It has the exterior walls removed for clarity.
The red beams are headers for the doors. There IS a large window between the control room and live room, but it's the only window. The rest are doors.
Top, Center, is the Drum Room.

knightfly · Post by **knightfly** » Wed Apr 09, 2003 12:32 pm

OK, DumbShit Mode back OFF (hopefully) - I should have known that with John involved, those would be sliders :=) Sooo, scratch the vocalist comment, even if there WERE simultaneous occupancies the vocalist could always walk thru the DOOR in front of the drum kit and into the booth - Actually, my only concern before the windows became doors was ease of access to the vocal booth once the drum kit was set up. It's enough of a pain to get a kit mic'ed, tuned, etc, without somebody bumping a critical mic out of position...

Did the inspector say that the panel between the walls HAD to be made of drywall? It would be so much better if that window could "bleed" into the wide wall gap - maybe at least use something like Celotex, that can breathe??? Or, maybe a Slat resonator with wide slots, that would act more like a bass trap because of the depth behind it? I have an idea or two, let me get back after I draw it in CAD, convert to another CAD format, then to a JPEG...

As to the different resonant frequency, here's what Sjoko used with great success against the railroad noise - RC, layer of 1/4" Fire rated gyp board, layer of 1/2" sound board, layer of 7/8" Fire rated gyp board. I'm not sure, though, whether the two sliders wouldn't negate the advantage in MTC the dissimilar leaves would give. Weakest link, and all...

I agree on the drums thing, it's kind of a non-issue what with windows metamorphosing into doors and all. :=) I've been kind of thinking about a similar wall somewhere in my studio, possibly one wall of the tracking room - You know those little "cottage stone" things at Home Depot that people use to make their own 1-2 foot high retaining walls? The stones are flat on top and bottom, and convex across the front, with a rough, "hand-hewn" sort of surface. I was thinking that an entire wall of them would be kind of like a thousand little "poly's", and might be acoustically useful... or, it could be an expensive woops, I'm still analyzing what I think it would do.

Soon as I get a little time to doodle, I'll post a pic of possible de-coupling scenarios... Steve

Michael Jones · Post by **Michael Jones** » Wed Apr 09, 2003 12:51 pm

...I should have known that with John involved, those would be sliders

Yeah. I really like the way they look at Left Bank.

No, it doesn't HAVE to be drywall, but when I mentioned cloth covered masonite, he kinda frowned.

I think Celotex would be acceptable, but finding a local supplier may be difficult. I'll have to search around for it.

I know what you're talking about regarding "those little retaining walls", but those things aren't designed to go to any appreciable height without having a tie-back system that goes back into the soil. Not very applicable here. And I doubt you could mortar them together with much success. They're just not designed for that.

Have you considered synthetic stone? Dense, but still lightweight. Might work out pretty darn well.

Thanks again for all your help!

Here's the drum room framed up (partially)

its roughly 14' at the back exterior wall, 10'-6" at the 2 sliders, and nearly 8' at the vocal booth wall.

knightfly · Post by **knightfly** » Sat Apr 12, 2003 6:49 am

Michael, sorry for the delay - I'm probably going to have even less time for this til after April 15 tax deadline -

I'm attaching a simple drawing of my possible solution to an isolated cover for your wall cavity - the isolators in the larger part are a kinetics corp item, probably expensive - after drawing that, I figured out a possible way to use RC-1 instead, shown as a separate detail on the left.

If your building inspector will allow it, I'd sure go for something more like cloth-covered 703 - I didn't scale it, but if he will allow the cover NOT to be sealed, I'd leave about 3/8" gap around the absorbent cover. If not, caulk - but solid connection would NOT be good, obviously...

Hope this either works for you or gives you an idea that would - Steve

knightfly · Post by **knightfly** » Sat Apr 12, 2003 7:01 am

Detail isn't too obvious in the RC method, I hope this one's bigger..

Michael Jones · Post by **Michael Jones** » Sun Apr 13, 2003 8:06 am

Steve, thanks for the details.
I'd like to know morre about the "Isolator", if you have any add'l info.

knightfly · Post by **knightfly** » Mon Apr 14, 2003 11:55 am

These guys have a TON of stuff, most of which is probably quite expensive, since they cater to professionals and heavy industry - If you want to download any of their CAD details, which I believe are all in a self-extracting .exe file, they want you to fill out their online form, after which their closest distributor will contact you (just once, in my case, then I lost the damn info before I could get it on the computer)

They have a LOT of CAD detail drawings, but for some reason my antiquated DXF to JPEG converter can't comprehend them, even though my (equally antiquated) DOS-based version of Generic Cadd 6.1 imports them just fine. Need to update some of this software, but HATE learning a new Proggie when the old one still works...

Anyway, here's their home page

http://www.kineticsnoise.com/

Here is the link to the specific isolator I drew -

http://www.kineticsnoise.com/kwsb.html

Their site is a little hard to follow - I had to call up the CAD drawing I downloaded several months ago, zoom in to that particular part, and get the model # before their search engine could help.

If you have any pgms that can read DXF format, it's worth it to download their CAD stuff just for education if nothing else.

Their contact phone # is on the site, if you want quick info I wouldn't wait til someone contacts you after filling in their little form - seems like it took a couple weeks in my case.

If you want a TRUE floated ceiling, as in hanging inside your walls but independently supported, they also sell the little "dual band" hanging isolators Everest refers to in his books, only slightly different design. Still uses an absorbent coupled with a spring, so as to dampen both low and high freq. structure-borne noise - Check this out;

http://www.kineticsnoise.com/ceilsyst.html

Oh, if your Inspector doesn't like masonite for the door frame gap, ask him if you can put individual boards on the subframe (oops, sorry, I "accidentally" left 3mm gaps between the boards... :=)

I still think using RC as in my second drawing would be cheaper and just as good, but it's your studio - Anything else I might be able to help with, just yell... Steve

Michael Jones · Post by **Michael Jones** » Wed Apr 16, 2003 2:38 pm

Thanks for the links and all the info Steve!

knightfly · Post by **knightfly** » Wed Apr 16, 2003 8:03 pm

My pleasure, Michael - just think how few mistakes I'll make on MY next facility after digging all this stuff up... :=) Steve