Where to start first-Acoustics Forum-Acoustic Fields Forum

Hello guys,
My room is 4.7m wide and 3.57 long.. Height of the room is 2.57m
On the floor i have hardwood, walls and ceiling are brick blocks and concrete….
It is a living and listening room and it is not treated….
Also, i am divorced so i can change this room how i would like without any problems aside from financial issues…
My speakers are open baffle for middle and treble and bass reflex for low end… Woofer is firing from a side of the speaker and reflex port is on the front panel of the speaker….

From what i understand – it is good to use diffusion behind the speakers and behind the listener… and on the side walls some absorbtion… on the ceiling mixed… right (in general)….???

Please let me know – where to start first….