Thanks for the answers, especially the link to the least primitive root calculator! Exactly what's needed.
Originally Posted by G. E.
In theory there's nothing wrong with 23x12 but I'd rather use two 13x12 instead as they give more flexibility in positioning.
Sure! But if you know for certain that a given area will be filled, isn't it better to avoid repetition? Or am I missing something?
Another question: would it be much point in building symmetrical arrays? Mirroring one of them, so the L/R sides of the room is identical seen from the sweet spot.
As for reflection points on the floor - that's an excellent place for the otherwise useless acoustic foam! Have two patches with 6" acoustic foam there now. The foam started out as a mixing board silencer for listening session. The big desk is gone now, have about the same rig as you with a modded table frame holding a computer inteface and the 2 outboard pieces I use for mastering. Unnatural or not, the foam on the floor seems to help a bit! I subjectively prefer it. Such foam is so cheap that it's at least worth the try to see if it suits each individuals preference.
The gravel pot idea is interesting. Perhaps some plants in the pots could do the same job with added aesthetic appeal?
Thanks again for the help! Am hoarding tools and materials now. Looking forward to get building.