Hey Sasi,
Always happy to get more advice. My room actually falls right at 30 sq. meters. Pretty soon I'm going to have eight 4'x2'x6" broadband absorbers with no hi-frequency reflection. I will also have six more 7.4'x2.75'x1' broadband absorbers w/ no hi frequency reflection. I also have carpet. So, I'm pretty sure I will be lacking in hi frequency energy.
This room will serve as both my monitoring and my tracking room. I plan to put the diffusers on the back wall away from the monitors. This should give enough distance with my current diffuser design to prevent lobing.
I'm primarily making these diffusers for tracking purposes. In my mind, they will make the acoustic guitars have more life. I plan to lay some plywood on the ground on the side of the room with the diffusers (maybe 5'-6' away) and mic my acoustic guitar and vocals there. Since 5'-6' is not the minimum distance away from the diffusers, this may cause problems. But from Ethan Winer's video, where he shows himself mic'ing acoustic guitar about 1' away from his diffusers, that sounded pretty freaking good. So, I'm thinking (correct me if I'm wrong), I will significantly improve the sound of my acoustic guitar recordings doing this.
Lastly, you mention that this diffusion only needs to take place at high frequencies (above 1 kHz) because this is the acoustic energy that is lost in the room. Is this true? It just seemed to me that more diffusion, the better. And maybe it would help randomize energy in the low-mids and break up room modes a bit. Am I wrong about this?
Should I make thinner (higher frequency) diffusers? Should I make diffusers at all?
Help.