Originally Posted by AwwDeOhh
Was going to use .5", but am going with 9/16 (only slightly larger) for a bit more absorption in the equation. i'm retro-fitting some 6" deep panels on the back wall (there's already QRD and some polys inbetween as well as QRD's on the back sides and a prd skyline on the ceiling) to help even out the rooms' decay a bit more (there's aLOT of absorpiton in my small room). I've got the low end pretty much under control (as much as it can be in this room) but the decay falls off more than i'd like in the mid-to-high end. If i don't like how they turn out (for the room), i can always put them on my Gobo for another tracking option.
Yes the acrylic plastic grid won't put up a fight against a drillbit, but it saves me from drawing out the grid, and if i can keep the drill from touching any side of the square, the hole should be darn close to vertical (there is only the very slightest bit of wiggle room w/ 9/16 bit)
With the pattern i'm using there will be 1.5" of "unused" space around the edges, which i figure should be plenty enough for mounting hardware or any trim i might add.
If you read through all
RPGs papers on BADs carefully, you will find a
diagram showing panels with 1/2" and 5/8" holes.
Results from the diagram show that 5/8" holes versus 1/2" will give:
Less reflection/diffusion for higher frequencies (usually seen as worse performance)
Less absorbtion for lower frequencies (usually seen as worse performance).
Personally I would not use that plastic grid, 37 squares wide, but mark out all
the holes with a good ruler / square directly on one piece of plywood, clamp together a number of plywood sheets and drill them all at the same time.
4 mm or 1/8" plywood is quite bendable even with out steaming, with little risk of cracking if you use 1/2" holes versus a 20 mm (3/4") inch grid. You will need D-shaped sides and also straight pieces of wood between these D-shapes, to nail down the plywood. It will bend up "a bit" in the middle otherwise. (This is from my practical DIY experience on BAD-copying.)