So actually, It's 2 window boxes, each with 2 panes in them. The panes are 200mm apart in each box, one is angled (more for light reflection). I used these in my last studio, where each box was part of the 2 different walls separating CR and Studio. The studio walls in my new studio will be 80kg/m2 (cladding only), while we will have only 40kg/m2 mass for the CR side.There will be 100mm gap between the 2 boxes. I think the panes are all 10mm lam. I'm pretty sure that one box is less efficient in terms of TL than the 80kg/m2 wall, but possibly more than the 40kg/m2 wall. So I wonder if the combination of the 2 boxes will perform well enough, commensurate with the corresponding or even combined mass of each wall system.
Now, some will say that I'd be better off with just one pane per box, 2 leaf instead of 4 leaf. But remember, I had these window boxes in my last studio, and they worked great! Measuring TL at the window vs the wall showed that the window was very close in that regard. The resonances passing through the 4 pane system were not problematic. Infact, my walls were 4 leaf as well in some sections (designed by Graeme Thirkell) and they were fine. John Sayers also told me he thinks 3 or 4 leaf can be fine sometimes, and all the talk about resonance issues are overstated.
But I wanted to hear some current thoughts on this. The boxes are 2.7m x 1.32 m x 360mm (deep). So presumably If I pulled out a pane from each, I could possibly create a gap between panes of around 700mm ! Is there anyone out there that feels certain this will be more effective for TL (including for low frequency) than the current 4 leaf arrangement? The boxes are made of 30mm MDF, I think...
