John Sayers' Recording Studio Design Forum Archive

The salesman at the glass company that I went today suggested that it's better with 2 pvb acoustic membranes for one laminate glass. Does that make much of a difference?

generally speaking, you want each layer in an isolating window to have a mass similar to the surface mass surrounding it. so if you have a wall with 2x 16mm gwb that is about 20kg/m2. so you would want the interior glass to match or slightly exceed that. so using laminated glass - you get the mass fairly easily, and the laminate helps to damp the resonances. if 12mm thick glass was required, then consider using 3x 4mm with 2 laminates, or 2x 6mm with 1 laminate layer, to achieve that. repeat the math for the other side.
if both sides needed 12mm, then consider 1 side with the 3x laminated panes, and the other 2x, as this changes their resonant characteristics and can reduce coincident frequencies which can reduce the isolation.

Τhank you very much for the response!
As far I understood, he suggested 6mm+2 pvb membranes+6mm . ( for the 12mm laminate glass that I want)
Is that even possible?

i guess it depends on the thickness of the polyvinyl butyral (PVB) materials, maybe he meant 0.2mm pvb? but it seems ok.

He said both pvb membranes will be 0.76mm total thickness.

ok