A speaker system such as a sound bar assembly having a plurality of speaker units and improved sound quality is provided. Opposing mating portions of front and back panels of the assembly or system are fused or welded together to form outer boundary and interior joints where the front and back panels are welded together. The front and back panels are spaced apart at their first and second ends to define first and second speaker compartments, respectively, separated by a central compartment. A speaker unit is positioned in each of the speaker compartments. The speaker compartments are acoustically isolated from one another by the interior joints to improve the sound quality.