Dude organise a time & I will take you through the headache hahaha. Come round sometime. I have some literature that will help but it is a total mindfuck.
The smaller the room the bigger the issues will be. Also the closer the room is to a perfect cube the worse it will be.
You will need to understand, standing waves, modes, reflections, abosrbtion, defraction, diffusion, dispersion, bass traps, resonantors etc etc.
Easier to talk face to face & give you the quick readers digest version to get you started. 5k is a healthy chunk, however it will disappear faster than your cum down a cheap hookers thoat, even faster if you get it wrong first time round.
There are no hard & fast ways of getting it right, but there are a million ways of spending $$$$ & getting it wrong.
