An attenuating apparatus for use with a positive displacement compressor. The device includes a bore formed in a housing of the compressor, the bore being positioned at an angle to a discharge chamber of the compressor and in fluid communication with the compressor discharge chamber. A plug is positioned within the bore, the plug movable within the bore to a preselected position. The plug has a first end in contact with a gas from the compressor discharge chamber and a second, opposite end being accessible from an exterior of the housing. A seal is positioned between the plug and the bore to seal an interface between the plug and the bore to prevent leakage of a gas from the compressor discharge chamber along the interface. The plug is lockable within the bore at the preselected position. The preselected position of the plug within the bore determines a bore length in fluid communication with the compressor discharge chamber, which attenuates sound from gas pulsations resulting from discharge of compressed gas from the operation of the compressor. The bore and plug are threaded to facilitate the adjustment of the plug within the bore.