What are ways to fix speaker dips in my speaker or audio room

Everything I have done what the acoustic engineer told me to do my problem is that 1speaker is louder than the other by 0.83 db 
I’m mainly wondering if that affects the imaging and sound stage?

My room is 9x6 meters and I’m using the long wall and the associated components are.

source: Lumin x1, Ayon CD 10, and for vinyl SME Model 20/2 with a Kuzma 4 point 9 tone arm is switch between 3 MC cartridges 

components PS audio stellar phono preamp, and audio research ref 6se and the amps are XA60.8 powered by the ps audio p12 power plant

Edit: my ceiling is 2.8 meters tall 

Ok imagine a prison cell I mean the bars of the cell my ceiling is made of wood, the wood that goes along my entire ceiling works exactly like a baffle so I’m guessing a lot of the bass just stay up there the acoustic engineer just says I don’t need anything up there it’s like one “BIG ASS BAFFLE ”

my ceiling is made from wood nothing else 

my acoustic engineer said I don’t need absorbers because of my ceiling there is no echo and it’s pretty lively sounding do to the sound leaving the room

Not sure this information is necessary:)
and me being all over the place with my grammar.