One speaker louder

i had the same problem for a while it just takes a lot of patients. it is all about first reflection and speaker placement

I agree with swapping speakers left to right as a troubleshooting technique. This may tell you if the problem is a speaker or something else (placement, electronics, source material).

I swapped them, but there is a real difference. You can still tell they are the same speaker, but one is quieter and less open.

If the quiet and less open speaker follows the swap, then the problem is the speaker, and not placement, equipment or source material.

If the swap results in the same channel sounding quiet and less open, then the issue is with something other than the speakers.

IMO.