Quote:
Originally Posted by avare  The panels will reflect sound at wavelengths shorter than the length of the distance between the holes, and be absorptive below that frequency. With ~20% open area, the panels are acoustically transparent. |
I'd just like to point out that the hardboard with holes (pegboard) available in
building supply stores that Rafael mentioned is nowhere near 20% perforation.
I think it's more like 1% which would not be transparent.
The BBC document does say they used 20%. I wonder where they got it ?
Paul P