Interesting.
How do these perform if multiple periods? I’m currently experimenting with a 1200mm period so we could compare easily with a total width of 2400mm (since yours are either ≈ 600mm or 800mm, 3 or 4 periods to reach 2400mm total i.e.). My effective depth will probably be fixed at 190mm (220mm total depth per panel) due to the material and production technique I’m using.
I know you prefer 1/6 octave graphs for diffusion and scattering coefficients, so the graphs below is in this format but in the appendix of AAaD (Cox/D´Antonio), 1/3 octave is used so I would prefer this option so one can compare (at least to some extent) with these values.
Also, it’s a bit quicker to render the graphs if 1/3 oct. heh
As we discussed via PM, the lack of modeling to predict temporal dispersion can be troublesome since the reported diffusion coefficients for some shapes looks “too good to be true”, like the single poly (ellipse) for instance (witch offers superior spatial dispersion but no temporal dispersion and therefore is not a good diffuser). I made some examples to illustrate the problem to other readers of this thread. I think the polar plot is useful get some clue on temporal dispersion. If there are no lobs, there is probably no “diffusion” in the time domain either. A FDTD (Finite Difference Time Domain) model would certainly be useful.
Random incidence for scattering and normalized diffusion coefficients, normal (0 deg) incidence for polar plots. All models 190mm effective depth:
One fined N7 QRD; 600mm, 190mm effective depth (220mm total), 1mm fins:
4 x fined N7 QRD; 600mm period, 2400mm total, 190mm effective depth (220mm total), 1mm fins:
One finless (no dividers) N7 QRD; 600mm, 190mm effective depth (220mm total):
4 x finless N7 QRD; 600mm period, 2400mm total, 190mm effective depth (220mm total):
One poly; 600mm, 190mm depth:
4 x 600mm polys; 2400mm total, 190mm depth:
One poly; 2400mm, 190mm depth:
Freeform (stepped, no fins): positive and negative panel @ 1200mm each, 2400mm total width, 190mm effective depth (220mm total):
Screens are from a beta version of AFMG Reflex, posted with permission. More info here:
New EASE Tools Go Beta - AFMG - Ahnert Feistel Media Group
Sincerely Jens Eklund