An acoustical barrier wall system for use as an external wall acoustical attenuator for sound sources, is disclosed. The wall system comprises a plurality of acoustical barrier panels adapted for vertically stacked co-operating engagement. There are first and second attachment members each having a first end anchored within the main body portion of the acoustical barrier panels and an opposite threaded second end extending outwardly beyond the main body portion. There are first and second upright bracing members, each having a corresponding plurality of attachment member receiving means spaced therealong, the attachment member receiving means being adapted to receive the respective first and second attachment members therein. Connecting means in the form of co-operating nuts adapted to connect the attachment members and the attachment member receiving means in secured relation to one another. The plurality of vertically stacked acoustical barrier panels are secured together by the attachment members, the first and second upright bracing members, and the connecting means to thereby form a wall section for unitary placement between a pair of spaced upright frame members adapted to supportingly receive the plurality of acoustical barrier panels in vertically stacked cooperative engagement therebetween. The first and second upright bracing members are adapted for secure fastening to the respective one of the pair of spaced upright frame members following the unitary placement of the wall section.