Abstract: A sound barrier cover for a compressor unit which has a housing provided by a substantially continuous wall which provided with a plurality of access ports therethrough. The barrier cover has first and second shell sections configured to lie close to the housing wall and substantially envelope the same wherein the shell sections are configured to provide two substantially longitudinally oriented halves each having sound absorbing material affixed to its inner surface. These halves have perimeters with portions thereof formed with mating tongue and groove structure and carry cooperating components of snap-fastener devices in close proximity to the perimeters. These snap-fastener devices are adapted to hold the perimeters in contact with each other and with the sound absorbing material in resilient contact with the housing.