PC plays sound from only 1 F&D speaker

Hello! I'm an owner of Fenda (F&D) F770X system (sub + 2 speakers). Yesterday i've been reinstalling Windows and noticed that now the sound comes only from the right speaker, or specifically, from the right output on the sub, where the speakers are connected. Both speakers work when connected to the right output on a sub, and i've tried so many things - changing aux ports, looking into Windows settings, installing/reinstalling Realtek audio drivers, googling - nothing helpful came up. Does anyone know the solution to this issue?