Walls-Walls & More Walls

[ozzie]

Steve- When you ask me:

why don't you tell me how much thickness you can use (total, from existing frame) for your added walls on the outside perimeter, and I'll draw a wall plan for you and explain each part of it... Steve

This is what comes to mind:

Well the stud is 3.5" wide so I'm thinking 3 or 4 pieces of sheetrock can fit into the studs without insulation

but then I'm thinking I need the insulation so with insulation I can put two pieces of sheetrock or

He could be asking me how much thickness I can use for my added walls on the outside perimeter because he doesn't know if it fits into my budget so if that the case just let me know how much thickness I need and I'll find a way to get the money so I can do the job.

-Tho' life is complicated only what you make to be-

Thank You
Ozzie

[knightfly]

Ozzie, mainly your drawing has too many air gaps - your outer metal + the sheet rock you put between studs is ONE leaf - after that, you should only have one air/insulation space, then ONE more leaf. That inner leaf will need to be at least two layers of sheet rock. This will mean you only have to build one more frame than the one that's already there.

If you put insulation between part of the outside frame studs, then you can either put up the other frame and insulate it, then put on your inside layers of sheet rock - OR, you can build the frame laying down on the floor, put your layers of sheet rock on the frame, and stand it up, caulking it and fastening it where it will sit. Doing it this second way is John's "inside out" wall construction - the main advantage is only having to build one more frame, and having a place to put acoustic treatment and cover it with cloth (the cloth staples to the frame, covering the insulation material that's being used as acoustic treatment.)

If you put sheet rock pieces between your outer studs up against the metal, you need to either put Tyvek up against the metal first or use "greenboard", which is special sheet rock designed for wet locations such as bathrooms. I would recommend BOTH.

Remember - you only want ONE air gap, and only TWO centers of mass. Adding more gaps and wallboard is a waste of time and money. It will do much more good if you use that extra wallboard to make the TWO centers of mass heavier. (like, 3 layers per leaf instead of 2)

Mass, then air, then mass. QUIT. I don't know how else to say this.

Take a look back in this thread where you posted the graphic of different STC rated walls - note the STC 50 wall? This is essentially what your last drawing shows. 3 leaves, two air spaces. Now, note the STC 57 wall - one LESS leaf, less material, MORE STC. Now, note the STC 63 wall - exact same amount of material as the STC 40 wall, but with the two inner boards moved to the outside so that there is only MASS, AIR, MASS.

The key here is placement - having two or more air gaps in a wall only serves to couple the wall surfaces together better, so that sound has an easier time getting through them. NOT what you want.

What I asked previously was how much space can you use for your outside walls, measured from the inside of the existing frame to the inner surface of the final wall? If you can give me that, I'll do two choices of wall for you and estimate the difference in STC for you... Steve

[cadesignr]

Well, heres my shot at it.
fitZ

[knightfly]

That'll do 'er, Fitz, thanks - looks like yer concrete hatch kinda "spilled over" a bit though - that fine Coos Bay wind blow the stuff around a bit?

Ozzie, all I'd add to that is to remember my comments about the "greenboard" and tyvek - that crappy tin isn't gonna stop much moisture, so you want a barrier and stuff that doesn't care about moisture as much. If you don't know what "greenboard" is, check with your local building supply. It's sheet rock for use around wet areas like bathrooms and kitchens.

Thanks again Rick, I might get a full 5 hours tonight... Later... Steve

[cadesignr]

Hey Steve,, no prob ole buddy. I've actually got a ton of things drawn, but didn't want to stick my stuff into your domain, but I know you've been dealin with them gators Can't whip em unless ya gits some shuteye once in a while. Ha! Just let me know if you need ANY drawing done and I'll be happy to do it. NOW that I know how to post em! By the way, I'll be posting my plan soon. Give ya something to try out those new gator rippin techniques on.

fitZ

ps....my concrete hatch contractor was lazy. He just covered it with earth.

[knightfly]

"ps....my concrete hatch contractor was lazy. He just covered it with earth" -

AHA!!!?! Another steenkin' cover-up, I KNEW it...

Come to think of it, it's just like REAL concrete contractors do


Again, thanks a mil, man - I'm actually gettin to the sack and it's only 1:30... Steve

[ozzie]

Ok guys I think I got it now, Tell me if I got the right:

I can use the second wall(inner wall) to soffit my monitors at a 30 degree angle, build my bass traps or even finish it off with a cloth finish?- example circled in yellow

Remember - you only want ONE air gap, and only TWO centers of mass. Adding more gaps and wallboard is a waste of time and money. It will do much more good if you use that extra wallboard to make the TWO centers of mass heavier. (like, 3 layers per leaf instead of 2)

So what your saying is I can put three or even four layers of sheetroock or some other material on each of the walls? I know I'm probably pushing it with the four layer. - example with orange arrows

-I hope I have this right-

Thank You
Ozzie

P.S.
Thank you Cadesignr for the drawing and everyone that help me

[knightfly]

" I can use the second wall(inner wall) to soffit my monitors at a 30 degree angle, build my bass traps or even finish it off with a cloth finish?" -

Not a good plan, ozzie - you would need to build your soffits/traps INSIDE the mass-air-mass envelope we've been talking about.

You have the wall design down now, but if you use part of that wall structure for "double duty", such as bass traps or speaker soffits, you will weaken your sound proofing.

Both those additions will need to be INSIDE of your "mass-air-mass" envelope, unless you don't need hardly any isolation at all.

If you build your inner leaf as an "inside out" wall, then you would want a cloth covering over the studs to cover the insulation that is acting as acoustic treatiemt.

However, this is NOT the thing to do for front, splayed walls or speaker soffits. Unless you're mixing surround, these surfaces, when part of a Reflection Free Zone with enough angle to eliminate early reflections, should be reflective. Only rear (and some ceiling) surfaces should be absorptive in a normal RFZ, NON-surround control room... Steve

[ozzie]

What's up Steve, My bad for taking so long to reply. My damn real job gets in the way sometimes.

Steve is there anyway to soffit my monitors at a 30 degree angle and build my bass traps with out weaking my soundproofing?

If there is away to do this or if there isn't can you tell me how to go about doing this with my inner wall?

that would be my reason for always adding a extra spring and leaf in my drawings because I wasn't sure if I could use the inner wall to soffit my monitors at a 30 degree angle and build my bass traps with out weaking my soundproofing.

Thank You
Ozzie

[knightfly]

Ozzie, check out Aaron's 3-D plans on this page

http://www.johnlsayers.com/phpBB2/viewt ... c&start=60

and the next one in the thread - then c'mon back and ask questions... Steve

[ozzie]

what's up Steve,

I took a look at Aaron's 3-D plans and made an outline of my studio with it. I don't know if I got this right but here it goes.

On Aaron's first 3-D plan he has double sheetrock for the inner wall and goes on from there with a enough space to soffit and build he's bass traps for he's splayed walls is this correct?

I'm thinking it's something like John's "inside out" wall design where I use the the inner leaf as an "inside out" wall but instead of finishing with a cloth finish like you explained to me before for example I soffit my monitors and build my bass traps and then finishing it off with some kind of material(like sheetrock ? ) for my splayed walls.

or do I just leave the inner wall open in other words no sheetrock where I have the yellow lines pointing to in the second 3-D drawing?

Thank You
Ozzie

[knightfly]

Ozzie, nice weather and tons to do, so I'll have to catch this tonite when I'm too tired to do anything but type... Steve

[cadesignr]

Holy crap....is that TWO sets of TWO LEAF systems....One for the outer shell, and one for the inner shells..man I AM confused now....so the BLUE lines are TWO leafs of the outer shell...is that correct? And the orange lines are TWO leafs of the room within the outer shell.....? Where have I been....wait, this can't be right.
I MUST be having a bad dream. PLEASE clarify this Steve, cause if that is correct......goodbye STC dreams. AND I've been in a haze....
fitZ

[knightfly]

Hey Rick, UTMAIA as usual, but bottom line - I've been pounding the 2-leaf thing into people's heads all this time mainly so they stop asking "what if I build a 6" block wall, then move in 2 feet and build a 4" gypsum wall, then move in another 18" and build a cardboard wall with saran wrap covering only one side, etc, WHAT IS MY STC? "

The reality is that yes, 2-leaf is the most efficient use of materials. The second reality is, that adding more leaves will not LOWER the STC of an existing wall, but it's NOT the most EFFICIENT use of materials. However, there are times when there is no choice (sound locks, splayed shells within buildings, etc)

I'm still working on a quorum on this among a few trusted authorities, and when I'm ready I'll update my comments, complete with graphics, on this forum.

Til then, f--- off, I'm busy (That's me, beside myself -and no, that wasn't the REAL "f--- off", just a joke)

Trust me, this WILL get cleared up within a few days... Steve

[ozzie]

I reposted my drawing because it seem to be making people confuse, it' a two leaf system with the blue line as the outer wall and the orange line as the inner wall but I am using the inner wall as a "inside out" wall and the green walls with space behind it is where I soffit my monitors and build my bass traps but I don't know if this is right because I'm just going off Aaron's 3-D plan. I'll repost my question again:

What's up Steve,

I took a look at Aaron's 3-D plans and made an outline of my studio with it. I don't know if I got this right but here it goes.

On Aaron's first 3-D plan he has double sheetrock for the inner wall and goes on from there with a enough space to soffit and build he's bass traps for he's splayed walls is this correct?

I'm thinking it's something like John's "inside out" wall design where I use the the inner leaf as an "inside out" wall but instead of finishing with a cloth finish like you explained to me before for example I soffit my monitors and build my bass traps and then finishing it off with some kind of material(like sheetrock ? ) for my splayed walls.

or do I just leave the inner wall open in other words no sheetrock where I have the yellow lines pointing to in the second 3-D drawing?

Thank You
Ozzie