Originally Posted by Buffstuffbuddha
hey xaMdaM you talked about the idea of room glass themrmal glass and so on. So let me ask you this.
They way it would be set up, the air gap between the windows would be about 19 inches. such as
gas gap ( this is one window just so im not unclear )
19 inch air gap
would it be cool to just go ahead and get their insulated glass because there is so much air already or should I get the laminated glass because there is so much air already?
Your ASCII art is identical to what I illustrated... just so we're both clear... I just didn't label the air gap as a gas gap, as in inert argon gas.
The assembly as you propose is technically M-A-M -(19")A- M-A-M, or a 4 leaf assembly.
As far as my understanding goes, a simple MAM will ALWAYS out perform every other assembly.
I would (and did) use a simple laminated glass MAM in my construction; 1" laminated on the Control Room side and 3/4" on the Tracking Room side.
The thing you really need to do is match the mass of the glass to the mass of your walls.
The wall for the CR is 2x8, 3/4" OSB, 2 layers of 5/8" FR Gypsum, plus acoustic treatment, and the TR wall is 2x6, 3/4" OSB, 2 layers of 5/8" FR Gypsum, plus acoustic treatment. So, the 1" laminated glass is equal to the mass of the control room wall and the 3/4" laminated glass is equal to the mass of the tracking room.
Depending on who the manufacturer of the thermal panes is, I would suspect that it is no more than 1/8" glass on each side of the argon gas, if not thinner. This is to account for typical 2x4 framing construction... and in a 4 leaf assembly, would be considerably less effective mass for low frequencies.
If they manufacture the panes in a standard commercial thickness of something thicker than 3/8" (e.g. individual panes thicker than 1/8") you might
be ok, but why risk it?
Most standard commercial rated glass is 1/4" laminated glass of two layers of 1/8", and is what I often see touted as the equiv mass of a 2x4 stud wall with 2 layers of 5/8" FR gypsum.
Obviously, you can do what you want, but using residential rated products rarely fills the bill for what is in reality a doubled up commercial application.
Hope this makes sense... (I'm still working on the 2nd cup of coffee)
So, how thick are your walls, and their finishes?