I will take a guess. Your set up in your room is not identical for both left and right speakers. One side is absorbing a little more sound due to room shape, furniture, rugs or something. Or one side could have more reflecting surfaces like windows or liquor bottles, not sure, can't quite tell from this angle.
Second guess would be one of the drivers in the weak side speaker is out. When you listen to music just gently touch each driver to make sure they are moving. Leave the tweeter alone however, much like x wives they hate to be touched.
Second guess would be one of the drivers in the weak side speaker is out. When you listen to music just gently touch each driver to make sure they are moving. Leave the tweeter alone however, much like x wives they hate to be touched.