A compressor apparatus has a housing (22) having first (53) and second (58) ports along a flowpath. One or more working elements (26, 28) cooperate with the housing to define a compression path between suction and discharge locations along the flowpath. A check valve (70) has a valve element having a first condition permitting downstream flow along the flowpath and a second condition blocking a reverse flow. Sound suppressing means (120, 220, 320) at least partially surround the flowpath upstream of the valve element (70).