Ian,
I don’t know how to respond to your post. Even though you’ve provided a diagram of the space, I couldn’t tell you the best places to put individual pieces of foam without being there.
Foam, by itself, is usually not the answer. It absorbs a disproportionate amount of high frequencies.
The correct approach is a combination of absorption and diffusion, in the right spots. If you’re only doing spoken word, trapping the corners is probably a waste of time.
All hard, parallel surfaces are problematic. walls, floors, ceilings, etc. The time-honored approach is to make sure that one of two parallel surface is treated, but there’s a lot more that goes in to getting good acoustics. Basic room dimensions themselves can have a significant effect on the generation of standing waves that can muck up your sound. This is not something to be experimented with if money is on the line. You need someone who can give proper solution, otherwise you are courting disappointment, to say the least.
Regards,
Ty Ford
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